vSphere Storage
VMware vSphere 6.5
VMware ESXi 6.5
vCenter Server 6.5
This document supports the version of each product listed and
supports all subsequent versions until the document is
replaced by a new edition. To check for more recent editions of
this document, see http://www.vmware.com/support/pubs.
EN-002312-03
vSphere Storage
You can find the most up-to-date technical documentation on the VMware Web site at:
http://www.vmware.com/support/
The VMware Web site also provides the latest product updates.
If you have comments about this documentation, submit your feedback to:
docfeedback@vmware.com
Copyright © 2009–2017 VMware, Inc. All rights reserved. Copyright and trademark information.
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Palo Alto, CA 94304
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Contents
About vSphere Storage
9
Updated Information 11
1 Introduction to Storage 13
Storage Virtualization 13
Types of Physical Storage 14
Target and Device Representations 17
Storage Device Characteristics 18
Supported Storage Adapters 20
Datastore Characteristics 21
How Virtual Machines Access Storage 24
Comparing Types of Storage 24
vSphere Storage APIs 25
2 Overview of Using ESXi with a SAN 27
ESXi and SAN Use Cases 28
Specifics of Using SAN Storage with ESXi 28
ESXi Hosts and Multiple Storage Arrays 29
Making LUN Decisions 29
Choosing Virtual Machine Locations 30
Layered Applications 31
Third-Party Management Applications 32
SAN Storage Backup Considerations 32
3 Using ESXi with Fibre Channel SAN 35
Fibre Channel SAN Concepts 35
Using Zoning with Fibre Channel SANs 36
How Virtual Machines Access Data on a Fibre Channel SAN
37
4 Configuring Fibre Channel Storage 39
ESXi Fibre Channel SAN Requirements
Installation and Setup Steps 40
N-Port ID Virtualization 41
39
5 Configuring Fibre Channel over Ethernet 45
Fibre Channel over Ethernet Adapters 45
Configuration Guidelines for Software FCoE
Set Up Networking for Software FCoE 46
Add Software FCoE Adapters 47
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6 Booting ESXi from Fibre Channel SAN 49
Boot from SAN Benefits 49
Boot from Fibre Channel SAN Requirements and Considerations
Getting Ready for Boot from SAN 50
Configure Emulex HBA to Boot from SAN 52
Configure QLogic HBA to Boot from SAN 53
50
7 Booting ESXi with Software FCoE 55
Requirements and Considerations for Software FCoE Boot 55
Best Practices for Software FCoE Boot 56
Set Up Software FCoE Boot 56
Troubleshooting Installation and Boot from Software FCoE 57
8 Best Practices for Fibre Channel Storage 59
Preventing Fibre Channel SAN Problems 59
Disable Automatic Host Registration 60
Optimizing Fibre Channel SAN Storage Performance
60
9 Using ESXi with iSCSI SAN 63
iSCSI SAN Concepts 63
How Virtual Machines Access Data on an iSCSI SAN 68
10 Configuring iSCSI Adapters and
Storage
69
ESXi iSCSI SAN Requirements 70
ESXi iSCSI SAN Restrictions 70
Setting LUN Allocations for iSCSI 70
Network Configuration and Authentication 71
Set Up Independent Hardware iSCSI Adapters 71
About Dependent Hardware iSCSI Adapters 74
About the Software iSCSI Adapter 77
Modify General Properties for iSCSI Adapters 81
Setting Up iSCSI Network 81
Using Jumbo Frames with iSCSI 91
Configuring Discovery Addresses for iSCSI Adapters 93
Configuring CHAP Parameters for iSCSI Adapters 94
Configuring Advanced Parameters for iSCSI 98
iSCSI Session Management 99
11 Booting from iSCSI SAN 103
General Boot from iSCSI SAN Recommendations 103
Prepare the iSCSI SAN 104
Configure Independent Hardware iSCSI Adapter for SAN Boot 104
iBFT iSCSI Boot Overview 105
12 Best Practices for iSCSI Storage 111
Preventing iSCSI SAN Problems 111
Optimizing iSCSI SAN Storage Performance 112
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Contents
Checking Ethernet Switch Statistics
115
13 Managing Storage Devices 117
Storage Device Characteristics 117
Understanding Storage Device Naming 119
Storage Rescan Operations 120
Identifying Device Connectivity Problems 122
Edit Configuration File Parameters 127
Enable or Disable the Locator LED on Storage Devices
Erase Storage Devices 128
128
14 Working with Flash Devices 129
Using Flash Devices with ESXi 130
Marking Storage Devices 130
Monitor Flash Devices 132
Best Practices for Flash Devices 132
About Virtual Flash Resource 133
Configuring Host Swap Cache 135
15 About VMware vSphere Flash Read Cache 137
DRS Support for Flash Read Cache 138
vSphere High Availability Support for Flash Read Cache
Configure Flash Read Cache for a Virtual Machine 138
Migrate Virtual Machines with Flash Read Cache 139
138
16 Working with Datastores 141
Understanding VMFS Datastores 142
Understanding Network File System Datastores 150
Creating Datastores 160
Managing Duplicate VMFS Datastores 163
Increasing VMFS Datastore Capacity 165
Administrative Operations for Datastores 166
Set Up Dynamic Disk Mirroring 173
Collecting Diagnostic Information for ESXi Hosts on a Storage Device
Checking Metadata Consistency with VOMA 177
Configuring VMFS Pointer Block Cache 179
174
17 Understanding Multipathing and Failover 181
Failover with Fibre Channel 181
Host-Based Failover with iSCSI 182
Array-Based Failover with iSCSI 184
Path Failover and Virtual Machines 185
Managing Multiple Paths 186
VMware Multipathing Module 187
Path Scanning and Claiming 189
Managing Storage Paths and Multipathing Plug-Ins
Scheduling Queues for Virtual Machine I/Os 200
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18 Raw Device Mapping 203
About Raw Device Mapping 203
Raw Device Mapping Characteristics 206
Create Virtual Machines with RDMs 208
Manage Paths for a Mapped LUN 209
19 Storage Policy Based Management 211
Virtual Machine Storage Policies 212
Working with Virtual Machine Storage Policies 212
Populating the VM Storage Policies Interface 213
Default Storage Policies 216
Creating and Managing VM Storage Policies 218
Storage Policies and Virtual Machines 227
20 Using Storage Providers 233
Storage Providers and Data Representation 234
Storage Provider Requirements and Considerations 235
Register Storage Providers 235
View Storage Provider Information 236
Unregister Storage Providers 236
Update Storage Providers 237
Refresh Storage Provider Certificates 237
21 Working with Virtual Volumes 239
Virtual Volumes Concepts 240
Virtual Volumes and Storage Protocols 244
Virtual Volumes Architecture 246
Virtual Volumes and VMware Certificate Authority 247
Snapshots and Virtual Volumes 248
Before You Enable Virtual Volumes 248
Configure Virtual Volumes 249
Provision Virtual Machines on Virtual Volumes Datastores 252
Virtual Volumes and Replication 256
Best Practices for Working with vSphere Virtual Volumes 260
22 Filtering Virtual Machine I/O 265
About I/O Filters 265
Using Flash Storage Devices with Cache I/O Filters 268
System Requirements for I/O Filters 268
Configure I/O Filters in the vSphere Environment 269
Managing I/O Filters 274
I/O Filter Guidelines and Best Practices 275
23 Storage Hardware Acceleration 277
Hardware Acceleration Benefits 277
Hardware Acceleration Requirements 278
Hardware Acceleration Support Status 278
Hardware Acceleration for Block Storage Devices 278
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Hardware Acceleration on NAS Devices 283
Hardware Acceleration Considerations 286
24 Storage Thick and Thin Provisioning 287
Virtual Disk Thin Provisioning 287
ESXi and Array Thin Provisioning 291
Storage Space Reclamation 293
25 Using vmkfstools 299
vmkfstools Command Syntax
vmkfstools Options 300
Index
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About vSphere Storage
vSphere Storage describes storage options available to you and explains how to configure your VMware
®
ESXi™ system and VMware vCenter Server so that you can use and manage different types of storage.
vSphere Storage explicitly concentrates on traditional types of storage, including Fibre Channel, iSCSI, and
NAS, and discusses specifics of using ESXi and vCenter Server in these environments. In addition, vSphere
Storage introduces storage virtualization mechanisms supported by ESXi and vCenter Server. vSphere Storage
®
explains how you can enable and use such virtualization technologies as VMware vSphere Flash Read
®
Cache™, VMware vSphere Virtual Volumes™, Storage Policy Based Management (SPBM), and I/O filters.
Intended Audience
This information is for experienced system administrators who are familiar with the virtual machine and
storage virtualization technologies, data center operations, and SAN storage concepts.
vSphere Web Client and vSphere Client
Task instructions in this guide are based on the vSphere Web Client. You can also perform most of the tasks
in this guide by using the new vSphere Client. The new vSphere Client user interface terminology, topology,
and workflow are closely aligned with the same aspects and elements of the vSphere Web Client user
interface. You can apply the vSphere Web Client instructions to the new vSphere Client unless otherwise
instructed.
Note Not all functionality in the vSphere Web Client has been implemented for the vSphere Client in the
vSphere 6.5 release. For an up-to-date list of unsupported functionality, see Functionality Updates for the
vSphere Client Guide at http://www.vmware.com/info?id=1413.
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Updated Information
This Updated Information is updated with each release of the product or when necessary.
This table provides the update history of the vSphere Storage.
Revision
Description
EN-002312-03
“NFS Protocols and ESXi,” on page 150 has been updated to clarify information about NFS 4.1 and Fault
Tolerance.
EN-002312-02
“Storage Space Reclamation,” on page 293 has been updated to include a video.
EN-002312-01
n
n
n
n
EN-002312-00
VMware, Inc.
The “Best Practices for Working with vSphere Virtual Volumes,” on page 260 section has been
updated with new information.
An incorrect statement that a host can support up to 1024 VMFS datastores has been removed from
“VMFS Datastores as Repositories,” on page 144. In vSphere 6.5, up to 512 VMFS5 or VMFS6
datastores are supported per host.
“Versions of VMFS Datastores,” on page 142 has been corrected to state that a host can support up to
512 datastores.
“Assign Tags to Datastores,” on page 215 now includes a video that illustrates how to use the
datastore tags.
Initial release.
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Introduction to Storage
1
This introduction describes storage options available in vSphere and explains how to configure your ESXi
host, so that it can use and manage different types of storage.
This chapter includes the following topics:
n
“Storage Virtualization,” on page 13
n
“Types of Physical Storage,” on page 14
n
“Target and Device Representations,” on page 17
n
“Storage Device Characteristics,” on page 18
n
“Supported Storage Adapters,” on page 20
n
“Datastore Characteristics,” on page 21
n
“How Virtual Machines Access Storage,” on page 24
n
“Comparing Types of Storage,” on page 24
n
“vSphere Storage APIs,” on page 25
Storage Virtualization
ESXi and vCenter Server support storage virtualization capabilities that include virtual machines, Virtual
SAN, Virtual Volumes, Storage Policy Based Management (SPBM), and so on.
ESXi provides host-level storage virtualization, which logically abstracts the physical storage layer from
virtual machines. An ESXi virtual machine uses a virtual disk to store its operating system, program files,
and other data associated with its activities. A virtual disk is a large physical file, or a set of files, that can be
copied, moved, archived, and backed up as easily as any other file. You can configure virtual machines with
multiple virtual disks.
To access virtual disks, a virtual machine uses virtual SCSI controllers. These virtual controllers include
BusLogic Parallel, LSI Logic Parallel, LSI Logic SAS, and VMware Paravirtual. These controllers are the only
types of SCSI controllers that a virtual machine can see and access.
Each virtual disk resides on a datastore that is deployed on physical storage. From the standpoint of the
virtual machine, each virtual disk appears as if it were a SCSI drive connected to a SCSI controller. Whether
the physical storage is being accessed through storage or network adapters on the host is typically
transparent to the guest operating system and applications on the virtual machine.
In addition to virtual disks, vSphere offers a mechanism called raw device mapping (RDM). RDM is useful
when a guest operating system inside a virtual machine requires direct access to a storage device. For
information about RDMs, see Chapter 18, “Raw Device Mapping,” on page 203.
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vSphere Storage
Other storage virtualization capabilities that ESXi and vCenter Server provide include Virtual SAN, virtual
flash resource, Virtual Volumes, and Storage Policy Based Management (SPBM). For information about
Virtual SAN, see the Administering VMware Virtual SAN documentation.
Types of Physical Storage
The ESXi storage management process starts with storage space that your storage administrator preallocates
on different storage systems.
ESXi supports the following types of storage:
Local Storage
Stores virtual machine files on internal or directly connected external storage
disks.
Networked Storage
Stores virtual machine files on external storage disks or arrays attached to
your host through a direct connection or through a high-speed network.
Local Storage
Local storage can be internal hard disks located inside your ESXi host, or it can be external storage systems
located outside and connected to the host directly through protocols such as SAS or SATA.
Local storage does not require a storage network to communicate with your host. You need a cable
connected to the storage unit and, when required, a compatible HBA in your host.
The following illustration depicts a virtual machine using local SCSI storage.
Figure 1‑1. Local Storage
Host
virtual
machine
SCSI
VMFS
In this example of a local storage topology, the host uses a single connection to a storage disk. On that disk,
you can create a VMFS datastore, which you use to store virtual machine disk files.
Although this storage configuration is possible, it is not a recommended topology. Using single connections
between storage arrays and hosts creates single points of failure (SPOF) that can cause interruptions when a
connection becomes unreliable or fails. However, because the majority of local storage devices do not
support multiple connections, you cannot use multiple paths to access local storage.
ESXi supports a variety of local storage devices, including SCSI, IDE, SATA, USB, and SAS storage systems.
Regardless of the type of storage you use, your host hides a physical storage layer from virtual machines.
Note You cannot use IDE/ATA or USB drives to store virtual machines.
Local storage does not support sharing across multiple hosts. Only one host has access to a datastore on a
local storage device. As a result, although you can use local storage to create virtual machines, it prevents
you from using VMware features that require shared storage, such as HA and vMotion.
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Chapter 1 Introduction to Storage
However, if you use a cluster of hosts that have just local storage devices, you can implement Virtual SAN.
Virtual SAN transforms local storage resources into software-defined shared storage and allows you to use
features that require shared storage. For details, see the Administering VMware Virtual SAN documentation.
Networked Storage
Networked storage consists of external storage systems that your ESXi host uses to store virtual machine
files remotely. Typically, the host accesses these systems over a high-speed storage network.
Networked storage devices are shared. Datastores on networked storage devices can be accessed by
multiple hosts concurrently. ESXi supports multiple networked storage technologies.
In addition to traditional networked storage that this topic covers, VMware supports virtualized shared
storage, such as Virtual SAN. Virtual SAN transforms internal storage resources of your ESXi hosts into
shared storage that provides such capabilities as High Availability and vMotion for virtual machines. For
details, see the Administering VMware Virtual SAN documentation.
Note The same LUN cannot be presented to an ESXi host or multiple hosts through different storage
protocols. To access the LUN, hosts must always use a single protocol, for example, either Fibre Channel
only or iSCSI only.
Fibre Channel (FC)
Stores virtual machine files remotely on an FC storage area network (SAN). FC SAN is a specialized highspeed network that connects your hosts to high-performance storage devices. The network uses Fibre
Channel protocol to transport SCSI traffic from virtual machines to the FC SAN devices.
To connect to the FC SAN, your host should be equipped with Fibre Channel host bus adapters (HBAs).
Unless you use Fibre Channel direct connect storage, you need Fibre Channel switches to route storage
traffic. If your host contains FCoE (Fibre Channel over Ethernet) adapters, you can connect to your shared
Fibre Channel devices by using an Ethernet network.
Fibre Channel Storage depicts virtual machines using Fibre Channel storage.
Figure 1‑2. Fibre Channel Storage
Host
virtual
machine
fibre
channel
HBA
SAN
VMFS
fibre array
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In this configuration, a host connects to a SAN fabric, which consists of Fibre Channel switches and storage
arrays, using a Fibre Channel adapter. LUNs from a storage array become available to the host. You can
access the LUNs and create datastores for your storage needs. The datastores use the VMFS format.
For specific information on setting up the Fibre Channel SAN, see Chapter 3, “Using ESXi with Fibre
Channel SAN,” on page 35.
Internet SCSI (iSCSI)
Stores virtual machine files on remote iSCSI storage devices. iSCSI packages SCSI storage traffic into the
TCP/IP protocol so that it can travel through standard TCP/IP networks instead of the specialized FC
network. With an iSCSI connection, your host serves as the initiator that communicates with a target, located
in remote iSCSI storage systems.
ESXi offers the following types of iSCSI connections:
Hardware iSCSI
Your host connects to storage through a third-party adapter capable of
offloading the iSCSI and network processing. Hardware adapters can be
dependent and independent.
Software iSCSI
Your host uses a software-based iSCSI initiator in the VMkernel to connect to
storage. With this type of iSCSI connection, your host needs only a standard
network adapter for network connectivity.
You must configure iSCSI initiators for the host to access and display iSCSI storage devices.
iSCSI Storage depicts different types of iSCSI initiators.
Figure 1‑3. iSCSI Storage
Host
virtual
machine
virtual
machine
software
adapter
iSCSI
HBA
ethernet
NIC
LAN
LAN
VMFS
iSCSI array
In the left example, the host uses the hardware iSCSI adapter to connect to the iSCSI storage system.
In the right example, the host uses a software iSCSI adapter and an Ethernet NIC to connect to the iSCSI
storage.
iSCSI storage devices from the storage system become available to the host. You can access the storage
devices and create VMFS datastores for your storage needs.
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Chapter 1 Introduction to Storage
For specific information on setting up the iSCSI SAN, see Chapter 9, “Using ESXi with iSCSI SAN,” on
page 63.
Network-attached Storage (NAS)
Stores virtual machine files on remote file servers accessed over a standard TCP/IP network. The NFS client
built into ESXi uses Network File System (NFS) protocol version 3 and 4.1 to communicate with the
NAS/NFS servers. For network connectivity, the host requires a standard network adapter.
NFS Storage depicts a virtual machine using the NFS volume to store its files. In this configuration, the host
connects to the NFS server, which stores the virtual disk files, through a regular network adapter.
Figure 1‑4. NFS Storage
Host
virtual
machine
ethernet
NIC
LAN
NFS
NAS appliance
For specific information on setting up NFS storage, see “Understanding Network File System Datastores,”
on page 150.
Shared Serial Attached SCSI (SAS)
Stores virtual machines on direct-attached SAS storage systems that offer shared access to multiple hosts.
This type of access permits multiple hosts to access the same VMFS datastore on a LUN.
Target and Device Representations
In the ESXi context, the term target identifies a single storage unit that the host can access. The terms device
and LUN describe a logical volume that represents storage space on a target. Typically, the terms device and
LUN, in the ESXi context, mean a storage volume presented to the host from a storage target and available
for formatting.
Different storage vendors present the storage systems to ESXi hosts in different ways. Some vendors present
a single target with multiple storage devices or LUNs on it, while others present multiple targets with one
LUN each.
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Figure 1‑5. Target and LUN Representations
target
LUN
LUN
LUN
target
target
target
LUN
LUN
LUN
storage array
storage array
In this illustration, three LUNs are available in each configuration. In one case, the host sees one target, but
that target has three LUNs that can be used. Each LUN represents an individual storage volume. In the
other example, the host sees three different targets, each having one LUN.
Targets that are accessed through the network have unique names that are provided by the storage systems.
The iSCSI targets use iSCSI names, while Fibre Channel targets use World Wide Names (WWNs).
Note ESXi does not support accessing the same LUN through different transport protocols, such as iSCSI
and Fibre Channel.
A device, or LUN, is identified by its UUID name. If a LUN is shared by multiple hosts, it must be presented
to all hosts with the same UUID.
Storage Device Characteristics
You can display all storage devices or LUNs available to the host, including all local and networked devices.
If you use third-party multipathing plug-ins, the storage devices available through the plug-ins also appear
on the list.
For each storage adapter, you can display a separate list of storage devices available for this adapter.
Generally, when you review storage devices, you see the following information.
Table 1‑1. Storage Device Information
18
Storage Device Information
Description
Name
Also called Display Name. It is a name that the ESXi host assigns to the device based on
the storage type and manufacturer. You can change this name to a name of your choice.
Identifier
A universally unique identifier that is intrinsic to the device.
Operational State
Indicates whether the device is mounted or unmounted. For details, see “Detach
Storage Devices,” on page 124.
LUN
Logical Unit Number (LUN) within the SCSI target. The LUN number is provided by
the storage system. If a target has only one LUN, the LUN number is always zero (0).
Type
Type of device, for example, disk or CD-ROM.
Drive Type
Information about whether the device is a flash drive or a regular HDD drive. For
information about flash drives, see Chapter 14, “Working with Flash Devices,” on
page 129.
Transport
Transportation protocol your host uses to access the device. The protocol depends on
the type of storage being used. See “Types of Physical Storage,” on page 14.
Capacity
Total capacity of the storage device.
Owner
The plug-in, such as the NMP or a third-party plug-in, that the host uses to manage
paths to the storage device. For details, see “Managing Multiple Paths,” on page 186.
Hardware Acceleration
Information about whether the storage device assists the host with virtual machine
management operations. The status can be Supported, Not Supported, or Unknown.
For details, see Chapter 23, “Storage Hardware Acceleration,” on page 277.
Sector Format
Indicates whether the device uses a traditional, 512n, or advanced sector format, such as
512e. For more information, see “Storage Device Formats and VMFS Datastores,” on
page 144.
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Chapter 1 Introduction to Storage
Table 1‑1. Storage Device Information (Continued)
Storage Device Information
Description
Location
A path to the storage device in the /vmfs/devices/ directory.
Partition Format
A partition scheme used by the storage device. It could be of a master boot record
(MBR) or GUID partition table (GPT) format. The GPT devices can support datastores
greater than 2 TB. For more information, see “Storage Device Formats and VMFS
Datastores,” on page 144.
Partitions
Primary and logical partitions, including a VMFS datastore, if configured.
Multipathing Policies (VMFS
datastores)
Path Selection Policy and Storage Array Type Policy the host uses to manage paths to
storage. For more information, see Chapter 17, “Understanding Multipathing and
Failover,” on page 181.
Paths (VMFS datastores)
Paths used to access storage and their status.
Display Storage Devices for a Host
Display all storage devices available to a host. If you use any third-party multipathing plug-ins, the storage
devices available through the plug-ins also appear on the list.
The Storage Devices view allows you to list the hosts' storage devices, analyze their information, and modify
properties.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
All storage devices available to the host are listed in the Storage Devices table.
4
To view details for a specific device, select the device from the list.
5
Use tabs under Device Details to access additional information and modify properties for the selected
device.
Tab
Description
Properties
View device properties and characteristics. View and modify multipathing
policies for the device.
Paths
Display paths available for the device. Disable or enable a selected path.
Display Storage Devices for an Adapter
Display a list of storage devices accessible through a specific storage adapter on the host.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters.
All storage adapters installed on the host are listed in the Storage Adapters table.
4
Select the adapter from the list and click the Devices tab.
Storage devices that the host can access through the adapter are displayed.
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Supported Storage Adapters
Storage adapters provide connectivity for your ESXi host to a specific storage unit or network.
ESXi supports different classes of adapters, including SCSI, iSCSI, RAID, Fibre Channel, Fibre Channel over
Ethernet (FCoE), and Ethernet. ESXi accesses the adapters directly through device drivers in the VMkernel.
Depending on the type of storage you use, you might need to enable and configure a storage adapter on
your host.
For information on setting up software FCoE adapters, see Chapter 5, “Configuring Fibre Channel over
Ethernet,” on page 45.
For information on configuring different types of iSCSI adapters, see Chapter 10, “Configuring iSCSI
Adapters and Storage,” on page 69.
View Storage Adapters Information
The host uses storage adapters to access different storage devices. You can display details for the available
storage adapters and review their information.
Prerequisites
You must enable certain adapters, for example software iSCSI or FCoE, before you can view their
information. To configure adapters, see the following:
Chapter 10, “Configuring iSCSI Adapters and Storage,” on page 69
n
n
Chapter 5, “Configuring Fibre Channel over Ethernet,” on page 45
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters.
4
To view details for a specific adapter, select the adapter from the list.
5
Use tabs under Adapter Details to access additional information and modify properties for the selected
adapter.
Typically, you see the following adapter characteristics.
20
Adapter Information
Description
Model
Model of the adapter.
Targets (Fibre Channel and
iSCSI)
Number of targets accessed through the adapter.
WWN (Fibre Channel)
World Wide Name formed according to Fibre Channel standards that uniquely
identifies the FC adapter.
iSCSI Name (iSCSI)
Unique name formed according to iSCSI standards that identifies the iSCSI adapter.
iSCSI Alias (iSCSI)
A friendly name used instead of the iSCSI name.
IP Address (independent
hardware iSCSI)
Address assigned to the iSCSI HBA.
Devices
All storage devices or LUNs the adapter can access.
Paths
All paths the adapter uses to access storage devices.
Properties
General adapter properties. For iSCSI and FCoE adapters, use this tab to configure
additional properties, for example, authentication.
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Chapter 1 Introduction to Storage
Datastore Characteristics
Datastores are logical containers, analogous to file systems, that hide specifics of each storage device and
provide a uniform model for storing virtual machine files. You can display all datastores available to your
hosts and analyze their properties.
Datastores are added to vCenter Server in the following ways:
n
You can create a VMFS datastore, an NFS version 3 or 4.1 datastore, or a Virtual Volumes datastore
using the New Datastore wizard. A Virtual SAN datastore is automatically created when you enable
Virtual SAN.
n
When you add an ESXi host to vCenter Server, all datastores on the host are added to vCenter Server.
The following table describes datastore details that you can see when you review datastores through the
vSphere Web Client. Certain characteristic might not be available or applicable to all types of datastores.
Table 1‑2. Datastore Information
Datastore
Information
Applicable Datastore Type
Description
Name
VMFS
NFS
Virtual SAN
Virtual Volumes
Editable name that you assign to a datastore. For
information on renaming a datastore, see “Change
Datastore Name,” on page 167.
File System Type
VMFS
NFS
Virtual SAN
Virtual Volumes
File system that the datastore uses. For information
about VMFS and NFS datastores and how to manage
them, see Chapter 16, “Working with Datastores,” on
page 141.
For information about Virtual SAN datastores, see the
Administering VMware Virtual SAN documentation.
For information about Virtual Volumes, see Chapter 21,
“Working with Virtual Volumes,” on page 239.
Device Backing
VMFS
NFS
Virtual SAN
Information about underlying storage, such as a storage
device on which the datastore is deployed (VMFS),
server and folder (NFS), or disk groups (Virtual SAN).
Protocol Endpoints
Virtual Volumes
Information about corresponding protocol endpoints.
See “Protocol Endpoints,” on page 242.
Extents
VMFS
Individual extents that the datastore spans and their
capacity.
Drive Type
VMFS
Type of the underlying storage device, such as a flash
drive or a regular HHD drive. For details, see
Chapter 14, “Working with Flash Devices,” on page 129.
Capacity
VMFS
NFS
Virtual SAN
Virtual Volumes
Includes total capacity, provisioned space, and free
space.
Mount Point
VMFS
NFS
Virtual SAN
Virtual Volumes
A path to the datastore in the /vmfs/volumes/
directory of the host.
VMware, Inc.
21
vSphere Storage
Table 1‑2. Datastore Information (Continued)
Datastore
Information
Applicable Datastore Type
Description
Capability Sets
VMFS
Note A multi-extent VMFS
datastore assumes capabilities of only
one of its extents.
NFS
Virtual SAN
Virtual Volumes
Information about storage data services that the
underlying storage entity provides. You cannot modify
them.
Storage I/O Control
VMFS
NFS
Information on whether cluster-wide storage I/O
prioritization is enabled. See the vSphere Resource
Management documentation.
Hardware
Acceleration
VMFS
NFS
Virtual SAN
Virtual Volumes
Information on whether the underlying storage entity
supports hardware acceleration. The status can be
Supported, Not Supported, or Unknown. For details, see
Chapter 23, “Storage Hardware Acceleration,” on
page 277.
Note NFS 4.1 does not support Hardware
Acceleration.
Tags
VMFS
NFS
Virtual SAN
Virtual Volumes
Datastore capabilities that you define and associate with
datastores in a form of tags. For information, see “Assign
Tags to Datastores,” on page 215.
Connectivity with
Hosts
VMFS
NFS
Virtual Volumes
Hosts where the datastore is mounted.
Multipathing
VMFS
Virtual Volumes
Path selection policy the host uses to access storage. For
more information, see Chapter 17, “Understanding
Multipathing and Failover,” on page 181.
Display Datastore Information
Access the Datastores view with the vSphere Web Client navigator.
The Datastores view lets you list all datastores available in the vSphere infrastructure inventory, analyze the
information, and modify properties. You can also use the view to create datastores.
Procedure
1
Use one of the following methods to navigate to datastores.
n
In the vSphere Web Client navigator, select vCenter Inventory Lists > Datastores.
n
Browse to an object that is a valid parent object of a datastore, such as a data center, cluster, or host
and click the Datastores tab.
Datastores that are available in the inventory appear in the center panel.
2
Use the icons to create a datastore or to perform basic tasks for a selected datastore.
Icon
Description
Create a new datastore.
Increase datastore capacity.
Navigate to the datastore file browser.
22
VMware, Inc.
Chapter 1 Introduction to Storage
Icon
Description
Mount a datastore to certain hosts.
Remove a datastore.
Unmount a datastore from certain hosts.
3
To view specific datastore details, click a selected datastore.
4
Use tabs to access additional information and modify datastore properties.
Tab
Description
Getting Started
View introductory information and access basic actions.
Summary
View statistics and configuration for the selected datastore.
Monitor
View alarms, performance data, resource allocation, events, and other status information for the
datastore.
Manage
View and modify datastore properties, alarm definitions, tags, and permissions. Use this tab to
access storage devices that back the datastore, and to view and edit multipathing details for the
datastore devices.
Hosts
View hosts where the datastore is mounted.
VMs
View virtual machines that reside on the datastore.
List Datastores for an Infrastructure Object
Display datastores for a specific parent object, such as a data center, cluster, or host.
Procedure
1
Use the vSphere Web Client object navigator to browse to an object that is a valid parent object of a
datastore, such as a data center, cluster, or host.
2
Click the Datastores tab.
If any datastores are configured for this object, they appear in the center Datastores panel.
3
Use the icons to create a datastore or to perform basic tasks for a selected datastore.
Icon
Description
Create a new datastore.
Increase datastore capacity.
Navigate to the datastore file browser.
Mount a datastore to certain hosts.
Remove a datastore.
Unmount a datastore from certain hosts.
4
VMware, Inc.
Use tabs to access additional information and modify datastore properties.
Tab
Description
Getting Started
View introductory information and access basic actions.
Summary
View statistics and configuration for the selected datastore.
23
vSphere Storage
Tab
Description
Monitor
View alarms, performance data, resource allocation, events, and other status information for the
datastore.
Manage
View and modify datastore properties, alarm definitions, tags, and permissions. Use this tab to
access storage devices that back the datastore, and to view and edit multipathing details for the
datastore devices.
Hosts
View hosts where the datastore is mounted.
VMs
View virtual machines that reside on the datastore.
How Virtual Machines Access Storage
When a virtual machine communicates with its virtual disk stored on a datastore, it issues SCSI commands.
Because datastores can exist on various types of physical storage, these commands are encapsulated into
other forms, depending on the protocol that the ESXi host uses to connect to a storage device.
ESXi supports Fibre Channel (FC), Internet SCSI (iSCSI), Fibre Channel over Ethernet (FCoE), and NFS
protocols. Regardless of the type of storage device your host uses, the virtual disk always appears to the
virtual machine as a mounted SCSI device. The virtual disk hides a physical storage layer from the virtual
machine’s operating system. This allows you to run operating systems that are not certified for specific
storage equipment, such as SAN, inside the virtual machine.
The following graphic depicts five virtual machines using different types of storage to illustrate the
differences between each type.
Figure 1‑6. Virtual machines accessing different types of storage
Host
requires TCP/IP connectivity
virtual
machine
virtual
machine
virtual
machine
virtual
machine
virtual
machine
SCSI
VMFS
Key
software
adapter
fibre
channel
HBA
iSCSI
HBA
SAN
LAN
ethernet
NIC
ethernet
NIC
LAN
LAN
physical
disk
datastore
virtual
disk
VMFS
fibre array
VMFS
iSCSI array
NFS
NAS appliance
Note This diagram is for conceptual purposes only. It is not a recommended configuration.
Comparing Types of Storage
Whether certain vSphere functionality is supported might depend on the storage technology that you use.
The following table compares networked storage technologies that ESXi supports.
24
VMware, Inc.
Chapter 1 Introduction to Storage
Table 1‑3. Networked Storage that ESXi Supports
Technology
Protocols
Transfers
Interface
Fibre Channel
FC/SCSI
Block access of data/LUN
FC HBA
Fibre Channel over
Ethernet
FCoE/SCSI
Block access of data/LUN
n
n
iSCSI
IP/SCSI
Block access of data/LUN
n
n
NAS
IP/NFS
File (no direct LUN access)
Converged Network Adapter (hardware
FCoE)
NIC with FCoE support (software FCoE)
iSCSI HBA or iSCSI-enabled NIC (hardware
iSCSI)
Network adapter (software iSCSI)
Network adapter
The following table compares the vSphere features that different types of storage support.
Table 1‑4. vSphere Features Supported by Storage
Storage
APIs Data
Protectio
n
Storage Type
Boot VM
vMotion
Datastore
RDM
VM Cluster
VMware
HA and
DRS
Local Storage
Yes
No
VMFS
No
Yes
No
Yes
Fibre Channel
Yes
Yes
VMFS
Yes
Yes
Yes
Yes
iSCSI
Yes
Yes
VMFS
Yes
Yes
Yes
Yes
NAS over NFS
Yes
Yes
NFS 3 and
NFS 4.1
No
No
Yes
Yes
Note Local storage supports a cluster of virtual machines on a single host (also known as a cluster in a
box). A shared virtual disk is required. For more information about this configuration, see the vSphere
Resource Management documentation.
vSphere Storage APIs
Storage APIs is a family of APIs used by third-party hardware, software, and storage providers to develop
components that enhance several vSphere features and solutions.
This Storage publication describes a number of Storage APIs that contribute to your storage environment.
For information about other APIs from this family, including vSphere APIs - Data Protection, see the
VMware Web site.
vSphere APIs for Storage Awareness
Also known as VASA, these APIs, either supplied by third-party vendors or offered by VMware, enable
communication between vCenter Server and underlying storage. Through VASA, storage entities can inform
vCenter Server about their configurations, capabilities, and storage health and events. In return, in certain
environments, VASA can deliver VM storage requirements from vCenter Server to a storage entity and
ensure that the storage layer meets the requirements.
VASA become essential when you work with Virtual Volumes, Virtual SAN, vSphere APIs for I/O Filtering
(VAIO), and storage VM policies. See Chapter 20, “Using Storage Providers,” on page 233.
VMware, Inc.
25
vSphere Storage
vSphere APIs for Array Integration
These APIs, also known as VAAI, include the following components:
n
Hardware Acceleration APIs. Allow arrays to integrate with vSphere to transparently offload certain
storage operations to the array. This integration significantly reduces CPU overhead on the host. See
Chapter 23, “Storage Hardware Acceleration,” on page 277.
n
Array Thin Provisioning APIs. Help to monitor space use on thin-provisioned storage arrays to prevent
out-of-space conditions, and to perform space reclamation. See “ESXi and Array Thin Provisioning,” on
page 291.
vSphere APIs for Multipathing
Known as the Pluggable Storage Architecture (PSA), these APIs allow storage partners to create and deliver
multipathing and load-balancing plug-ins that are optimized for each array. Plug-ins communicate with
storage arrays and determine the best path selection strategy to increase I/O performance and reliability
from the ESXi host to the storage array. For more information, see “Managing Multiple Paths,” on page 186.
26
VMware, Inc.
Overview of Using ESXi with a SAN
2
Using ESXi with a SAN improves flexibility, efficiency, and reliability. Using ESXi with a SAN also supports
centralized management, failover, and load balancing technologies.
The following are benefits of using ESXi with a SAN:
n
You can store data securely and configure multiple paths to your storage, eliminating a single point of
failure.
n
Using a SAN with ESXi systems extends failure resistance to the server. When you use SAN storage, all
applications can instantly be restarted on another host after the failure of the original host.
n
You can perform live migration of virtual machines using VMware vMotion.
n
Use VMware High Availability (HA) in conjunction with a SAN to restart virtual machines in their last
known state on a different server if their host fails.
n
Use VMware Fault Tolerance (FT) to replicate protected virtual machines on two different hosts. Virtual
machines continue to function without interruption on the secondary host if the primary one fails.
n
Use VMware Distributed Resource Scheduler (DRS) to migrate virtual machines from one host to
another for load balancing. Because storage is on a shared SAN array, applications continue running
seamlessly.
n
If you use VMware DRS clusters, put an ESXi host into maintenance mode to have the system migrate
all running virtual machines to other ESXi hosts. You can then perform upgrades or other maintenance
operations on the original host.
The portability and encapsulation of VMware virtual machines complements the shared nature of this
storage. When virtual machines are located on SAN-based storage, you can quickly shut down a virtual
machine on one server and power it up on another server, or suspend it on one server and resume operation
on another server on the same network. This ability allows you to migrate computing resources while
maintaining consistent shared access.
This chapter includes the following topics:
n
“ESXi and SAN Use Cases,” on page 28
n
“Specifics of Using SAN Storage with ESXi,” on page 28
n
“ESXi Hosts and Multiple Storage Arrays,” on page 29
n
“Making LUN Decisions,” on page 29
n
“Choosing Virtual Machine Locations,” on page 30
n
“Layered Applications,” on page 31
n
“Third-Party Management Applications,” on page 32
VMware, Inc.
27
vSphere Storage
n
“SAN Storage Backup Considerations,” on page 32
ESXi and SAN Use Cases
When used with a SAN, ESXi can benefit from multiple vSphere features, including Storage vMotion,
Distributed Resource Scheduler (DRS), High Availability, and so on.
Using ESXi in conjunction with a SAN is effective for the following tasks:
Storage consolidation
and simplification of
storage layout
If you are working with multiple hosts, and each host is running multiple
virtual machines, the storage on the hosts is no longer sufficient and external
storage is required. Choose a SAN for external storage to provide a simpler
system architecture along with other benefits.
Maintenance with zero
downtime
When performing ESXi host or infrastructure maintenance, use vMotion to
migrate virtual machines to other host. If shared storage is on the SAN, you
can perform maintenance without interruptions to the users of the virtual
machines. Virtual machine working processes continue throughout a
migration.
Load balancing
You can add a host to a DRS cluster, and the host's resources become part of
the cluster's resources. The distribution and usage of CPU and memory
resources for all hosts and virtual machines in the cluster are continuously
monitored. DRS compares these metrics to an ideal resource utilization. Ideal
utilization takes into account the attributes of the cluster's resource pools and
virtual machines, the current demand, and the imbalance target. It then
performs (or recommends) virtual machine migrations accordingly.
Disaster recovery
You can use VMware High Availability to configure multiple ESXi hosts as a
cluster to provide rapid recovery from outages and cost-effective high
availability for applications running in virtual machines.
Simplified array
migrations and storage
upgrades
When you purchase new storage systems or arrays, use Storage vMotion to
perform live automated migration of virtual machine disk files from existing
storage to their new destination without interruptions to the users of the
virtual machines.
Specifics of Using SAN Storage with ESXi
Using a SAN in conjunction with an ESXi host differs from traditional SAN usage in a variety of ways.
When you use SAN storage with ESXi, keep in mind the following considerations:
28
n
You cannot use SAN administration tools to directly access operating systems of virtual machines that
use the storage. With traditional tools, you can monitor only the VMware ESXi operating system. You
use the vSphere Web Client to monitor virtual machines.
n
The HBA visible to the SAN administration tools is part of the ESXi system, not part of the virtual
machine.
n
Typically, your ESXi system performs multipathing for you.
VMware, Inc.
Chapter 2 Overview of Using ESXi with a SAN
ESXi Hosts and Multiple Storage Arrays
An ESXi host can access storage devices presented from multiple storage arrays, including arrays from
different vendors.
When you use multiple arrays from different vendors, the following considerations apply:
n
If your host uses the same Storage Array Type Plugin (SATP) for multiple arrays, be careful when you
need to change the default Path Selection Policy (PSP) for that SATP. The change will apply to all arrays.
For information on SATPs and PSPs, see Chapter 17, “Understanding Multipathing and Failover,” on
page 181.
n
Some storage arrays make recommendations on queue depth and other settings. Typically, these
settings are configured globally at the ESXi host level. Making a change for one array impacts other
arrays that present LUNs to the host. For information on changing queue depth, see the VMware
knowledge base article at http://kb.vmware.com/kb/1267.
n
Use single-initiator-single-target zoning when zoning ESXi hosts to Fibre Channel arrays. With this type
of configuration, fabric related events that occur on one array do not impact other arrays. For more
information about zoning, see “Using Zoning with Fibre Channel SANs,” on page 36.
Making LUN Decisions
You must plan how to set up storage for your ESXi systems before you format LUNs with VMFS datastores.
When you make your LUN decision, keep in mind the following considerations:
n
Each LUN should have the correct RAID level and storage characteristic for the applications running in
virtual machines that use the LUN.
n
Each LUN must contain only one VMFS datastore.
n
If multiple virtual machines access the same VMFS, use disk shares to prioritize virtual machines.
You might want fewer, larger LUNs for the following reasons:
n
More flexibility to create virtual machines without asking the storage administrator for more space.
n
More flexibility for resizing virtual disks, doing snapshots, and so on.
n
Fewer VMFS datastores to manage.
You might want more, smaller LUNs for the following reasons:
n
Less wasted storage space.
n
Different applications might need different RAID characteristics.
n
More flexibility, as the multipathing policy and disk shares are set per LUN.
n
Use of Microsoft Cluster Service requires that each cluster disk resource is in its own LUN.
n
Better performance because there is less contention for a single volume.
When the storage characterization for a virtual machine is not available, there is often no simple method to
determine the number and size of LUNs to provision. You can experiment using either a predictive or
adaptive scheme.
VMware, Inc.
29
vSphere Storage
Use the Predictive Scheme to Make LUN Decisions
When setting up storage for ESXi systems, before creating VMFS datastores, you must decide on the size
and number of LUNs to provision. You can experiment using the predictive scheme.
Procedure
1
Provision several LUNs with different storage characteristics.
2
Create a VMFS datastore on each LUN, labeling each datastore according to its characteristics.
3
Create virtual disks to contain the data for virtual machine applications in the VMFS datastores created
on LUNs with the appropriate RAID level for the applications' requirements.
4
Use disk shares to distinguish high-priority from low-priority virtual machines.
Note Disk shares are relevant only within a given host. The shares assigned to virtual machines on
one host have no effect on virtual machines on other hosts.
5
Run the applications to determine whether virtual machine performance is acceptable.
Use the Adaptive Scheme to Make LUN Decisions
When setting up storage for ESXi hosts, before creating VMFS datastores, you must decide on the number
and size of LUNS to provision. You can experiment using the adaptive scheme.
Procedure
1
Provision a large LUN (RAID 1+0 or RAID 5), with write caching enabled.
2
Create a VMFS on that LUN.
3
Create four or five virtual disks on the VMFS.
4
Run the applications to determine whether disk performance is acceptable.
If performance is acceptable, you can place additional virtual disks on the VMFS. If performance is not
acceptable, create a new, large LUN, possibly with a different RAID level, and repeat the process. Use
migration so that you do not lose virtual machines data when you recreate the LUN.
Choosing Virtual Machine Locations
When you’re working on optimizing performance for your virtual machines, storage location is an
important factor. A trade-off always exists between expensive storage that offers high performance and high
availability and storage with lower cost and lower performance.
Storage can be divided into different tiers depending on a number of factors:
30
n
High Tier. Offers high performance and high availability. Might offer built-in snapshots to facilitate
backups and point-in-time (PiT) restorations. Supports replication, full storage processor redundancy,
and SAS drives. Uses high-cost spindles.
n
Mid Tier. Offers mid-range performance, lower availability, some storage processor redundancy, and
SCSI or SAS drives. May offer snapshots. Uses medium-cost spindles.
n
Lower Tier. Offers low performance, little internal storage redundancy. Uses low end SCSI drives or
SATA (serial low-cost spindles).
VMware, Inc.
Chapter 2 Overview of Using ESXi with a SAN
Not all applications need to be on the highest-performance, most-available storage—at least not throughout
their entire life cycle.
Note If you need some of the functionality of the high tier, such as snapshots, but do not want to pay for it,
you might be able to achieve some of the high-performance characteristics in software. For example, you can
create snapshots in software.
When you decide where to place a virtual machine, ask yourself these questions:
n
How critical is the virtual machine?
n
What are its performance and availability requirements?
n
What are its PiT restoration requirements?
n
What are its backup requirements?
n
What are its replication requirements?
A virtual machine might change tiers throughout its life cycle because of changes in criticality or changes in
technology that push higher-tier features to a lower tier. Criticality is relative and might change for a variety
of reasons, including changes in the organization, operational processes, regulatory requirements, disaster
planning, and so on.
Layered Applications
SAN administrators customarily use specialized array-based software for backup, disaster recovery, data
mining, forensics, and configuration testing.
Storage providers typically supply two types of advanced services for their LUNs: snapshotting and
replication.
n
Snapshotting creates space with efficient copies of LUNs that share common blocks of data. In general,
snapshotting is used locally on the same storage systems as the primary LUN for quick backups,
application testing, forensics, or data mining.
n
Replication creates full copies of LUNs. Replicas are usually made to separate storage systems, possibly
separate sites to protect against major outages that incapacitate or destroy an entire array or site.
When you use an ESXi system in conjunction with a SAN, you must decide whether array-based or hostbased tools are more suitable for your particular situation.
Array-Based (Third-Party) Solution
When you use an ESXi system in conjunction with a SAN, you must decide whether array-based tools are
more suitable for your particular situation.
When you consider an array-based solution, keep in mind the following points:
n
Array-based solutions usually result in more comprehensive statistics. With RDMs, data always takes
the same path, which results in easier performance management.
n
Security is more transparent to the storage administrator when you use an RDM and an array-based
solution because with RDMs, virtual machines more closely resemble physical machines.
n
If you use an array-based solution, physical compatibility RDMs are often used for the storage of virtual
machines. If you do not intend to use RDMs, check the storage vendor documentation to see if
operations on LUNs with VMFS volumes are supported. If you use array operations on VMFS LUNs,
carefully read the section on resignaturing.
VMware, Inc.
31
vSphere Storage
File-Based (VMFS) Solution
When you use an ESXi system in conjunction with a SAN, you must decide whether file-based tools are
more suitable for your particular situation.
When you consider a file-based solution that uses VMware tools and VMFS instead of the array tools, be
aware of the following points:
n
Using VMware tools and VMFS is better for provisioning. One large LUN is allocated and
multiple .vmdk files can be placed on that LUN. With an RDM, a new LUN is required for each virtual
machine.
n
Snapshotting is included with your ESXi host at no extra cost.
n
Using VMFS is easier for ESXi administrators.
n
ESXi administrators who use the file-based solution are more independent from the SAN administrator.
Third-Party Management Applications
You can use third-party management applications in conjunction with your ESXi host.
Most SAN hardware is packaged with storage management software. In many cases, this software is a web
application that can be used with any web browser connected to your network. In other cases, this software
typically runs on the storage system or on a single server, independent of the servers that use the SAN for
storage.
Use this third-party management software for the following tasks:
n
Storage array management, including LUN creation, array cache management, LUN mapping, and
LUN security.
n
Setting up replication, check points, snapshots, or mirroring.
If you decide to run the SAN management software on a virtual machine, you gain the benefits of running a
virtual machine, including failover using vMotion and VMware HA. Because of the additional level of
indirection, however, the management software might not be able to see the SAN. In this case, you can use
an RDM.
Note Whether a virtual machine can run management software successfully depends on the particular
storage system.
SAN Storage Backup Considerations
Having a proper backup strategy is one of the most important aspects of SAN management. In the SAN
environment, backups have two goals. The first goal is to archive online data to offline media. This process
is repeated periodically for all online data on a time schedule. The second goal is to provide access to offline
data for recovery from a problem. For example, database recovery often requires retrieval of archived log
files that are not currently online.
Scheduling a backup depends on a number of factors:
32
n
Identification of critical applications that require more frequent backup cycles within a given period of
time.
n
Recovery point and recovery time goals. Consider how precise your recovery point needs to be, and
how long you are willing to wait for it.
n
The rate of change (RoC) associated with the data. For example, if you are using
synchronous/asynchronous replication, the RoC affects the amount of bandwidth required between the
primary and secondary storage devices.
VMware, Inc.
Chapter 2 Overview of Using ESXi with a SAN
n
Overall impact on SAN environment, storage performance (while backing up), and other applications.
n
Identification of peak traffic periods on the SAN (backups scheduled during those peak periods can
slow the applications and the backup process).
n
Time to schedule all backups within the data center.
n
Time it takes to back up an individual application.
n
Resource availability for archiving data; usually offline media access (tape).
Include a recovery-time objective for each application when you design your backup strategy. That is,
consider the time and resources necessary to perform a backup. For example, if a scheduled backup stores
so much data that recovery requires a considerable amount of time, examine the scheduled backup. Perform
the backup more frequently, so that less data is backed up at a time and the recovery time decreases.
If a particular application requires recovery within a certain time frame, the backup process needs to
provide a time schedule and specific data processing to meet this requirement. Fast recovery can require the
use of recovery volumes that reside on online storage to minimize or eliminate the need to access slow
offline media for missing data components.
Using Third-Party Backup Packages
You can use third-party backup solutions to protect system, application, and user data in your virtual
machines.
VMware offers the Storage APIs - Data Protection to work in conjunction with third-party products. When
using the APIs, third-party software can perform backups without loading ESXi hosts with the processing of
backup tasks.
The third-party products using the Storage APIs - Data Protection can perform the following backup tasks:
n
Perform full, differential, and incremental image backup and restore of virtual machines.
n
Perform file-level backup of virtual machines that use supported Windows and Linux operating
systems.
n
Ensure data consistency by using Microsoft Volume Shadow Copy Services (VSS) for virtual machines
that run supported Microsoft Windows operating systems.
Because the Storage APIs - Data Protection leverage the snapshot capabilities of VMFS, backups that you can
perform do not require downtime for virtual machines. These backups are nondisruptive, can be performed
at any time, and do not need extended backup windows.
For information about the Storage APIs - Data Protection and integration with backup products, see the
VMware Web site or contact you backup vendor.
VMware, Inc.
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vSphere Storage
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VMware, Inc.
Using ESXi with Fibre Channel SAN
3
When you set up ESXi hosts to use FC SAN storage arrays, special considerations are necessary. This section
provides introductory information about how to use ESXi with a FC SAN array.
This chapter includes the following topics:
n
“Fibre Channel SAN Concepts,” on page 35
n
“Using Zoning with Fibre Channel SANs,” on page 36
n
“How Virtual Machines Access Data on a Fibre Channel SAN,” on page 37
Fibre Channel SAN Concepts
If you are an ESXi administrator planning to set up hosts to work with SANs, you must have a working
knowledge of SAN concepts. You can find information about SANs in print and on the Internet. Because this
industry changes constantly, check these resources frequently.
If you are new to SAN technology, familiarize yourself with the basic terminology.
A storage area network (SAN) is a specialized high-speed network that connects computer systems, or host
servers, to high performance storage subsystems. The SAN components include host bus adapters (HBAs) in
the host servers, switches that help route storage traffic, cables, storage processors (SPs), and storage disk
arrays.
A SAN topology with at least one switch present on the network forms a SAN fabric.
To transfer traffic from host servers to shared storage, the SAN uses the Fibre Channel (FC) protocol that
packages SCSI commands into Fibre Channel frames.
To restrict server access to storage arrays not allocated to that server, the SAN uses zoning. Typically, zones
are created for each group of servers that access a shared group of storage devices and LUNs. Zones define
which HBAs can connect to which SPs. Devices outside a zone are not visible to the devices inside the zone.
Zoning is similar to LUN masking, which is commonly used for permission management. LUN masking is a
process that makes a LUN available to some hosts and unavailable to other hosts.
When transferring data between the host server and storage, the SAN uses a technique known as
multipathing. Multipathing allows you to have more than one physical path from the ESXi host to a LUN on
a storage system.
Generally, a single path from a host to a LUN consists of an HBA, switch ports, connecting cables, and the
storage controller port. If any component of the path fails, the host selects another available path for I/O. The
process of detecting a failed path and switching to another is called path failover.
VMware, Inc.
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vSphere Storage
Ports in Fibre Channel SAN
In the context of this document, a port is the connection from a device into the SAN. Each node in the SAN,
such as a host, a storage device, or a fabric component has one or more ports that connect it to the SAN.
Ports are identified in a number of ways.
WWPN (World Wide Port
Name)
A globally unique identifier for a port that allows certain applications to
access the port. The FC switches discover the WWPN of a device or host and
assign a port address to the device.
Port_ID (or port
address)
Within a SAN, each port has a unique port ID that serves as the FC address
for the port. This unique ID enables routing of data through the SAN to that
port. The FC switches assign the port ID when the device logs in to the fabric.
The port ID is valid only while the device is logged on.
When N-Port ID Virtualization (NPIV) is used, a single FC HBA port (N-port) can register with the fabric by
using several WWPNs. This method allows an N-port to claim multiple fabric addresses, each of which
appears as a unique entity. When ESXi hosts use a SAN, these multiple, unique identifiers allow the
assignment of WWNs to individual virtual machines as part of their configuration.
Fibre Channel Storage Array Types
ESXi supports different storage systems and arrays.
The types of storage that your host supports include active-active, active-passive, and ALUA-compliant.
Active-active storage
system
Allows access to the LUNs simultaneously through all the storage ports that
are available without significant performance degradation. All the paths are
active at all times, unless a path fails.
Active-passive storage
system
A system in which one storage processor is actively providing access to a
given LUN. The other processors act as backup for the LUN and can be
actively providing access to other LUN I/O. I/O can be successfully sent only
to an active port for a given LUN. If access through the active storage port
fails, one of the passive storage processors can be activated by the servers
accessing it.
Asymmetrical storage
system
Supports Asymmetric Logical Unit Access (ALUA). ALUA-compliant
storage systems provide different levels of access per port. ALUA allows
hosts to determine the states of target ports and prioritize paths. The host
uses some of the active paths as primary while others as secondary.
Using Zoning with Fibre Channel SANs
Zoning provides access control in the SAN topology. Zoning defines which HBAs can connect to which
targets. When you configure a SAN by using zoning, the devices outside a zone are not visible to the devices
inside the zone.
Zoning has the following effects:
36
n
Reduces the number of targets and LUNs presented to a host.
n
Controls and isolates paths in a fabric.
n
Can prevent non-ESXi systems from accessing a particular storage system, and from possibly
destroying VMFS data.
n
Can be used to separate different environments, for example, a test from a production environment.
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Chapter 3 Using ESXi with Fibre Channel SAN
With ESXi hosts, use a single-initiator zoning or a single-initiator-single-target zoning. The latter is a
preferred zoning practice. Using the more restrictive zoning prevents problems and misconfigurations that
can occur on the SAN.
For detailed instructions and best zoning practices, contact storage array or switch vendors.
How Virtual Machines Access Data on a Fibre Channel SAN
ESXi stores a virtual machine's disk files within a VMFS datastore that resides on a SAN storage device.
When virtual machine guest operating systems issue SCSI commands to their virtual disks, the SCSI
virtualization layer translates these commands to VMFS file operations.
When a virtual machine interacts with its virtual disk stored on a SAN, the following process takes place:
1
When the guest operating system in a virtual machine reads or writes to a SCSI disk, it issues SCSI
commands to the virtual disk.
2
Device drivers in the virtual machine’s operating system communicate with the virtual SCSI controllers.
3
The virtual SCSI controller forwards the command to the VMkernel.
4
The VMkernel performs the following tasks.
5
6
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a
Locates the file in the VMFS volume that corresponds to the guest virtual machine disk.
b
Maps the requests for the blocks on the virtual disk to blocks on the appropriate physical device.
c
Sends the modified I/O request from the device driver in the VMkernel to the physical HBA.
The physical HBA performs the following tasks.
a
Packages the I/O request according to the rules of the FC protocol.
b
Transmits the request to the SAN.
Depending on a port the HBA uses to connect to the fabric, one of the SAN switches receives the
request and routes it to the storage device that the host wants to access.
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Configuring Fibre Channel Storage
4
When you use ESXi systems with SAN storage, specific hardware and system requirements exist.
This chapter includes the following topics:
n
“ESXi Fibre Channel SAN Requirements,” on page 39
n
“Installation and Setup Steps,” on page 40
n
“N-Port ID Virtualization,” on page 41
ESXi Fibre Channel SAN Requirements
In preparation for configuring your SAN and setting up your ESXi system to use SAN storage, review the
requirements and recommendations.
n
Make sure that the SAN storage hardware and firmware combinations you use are supported in
conjunction with ESXi systems. For an up-to-date list, see the VMware Compatibility Guide.
n
Configure your system to have only one VMFS volume per LUN.
n
Unless you are using diskless servers, do not set up the diagnostic partition on a SAN LUN.
In the case of diskless servers that boot from a SAN, a shared diagnostic partition is appropriate.
n
Use RDMs to access raw disks. For information, see Chapter 18, “Raw Device Mapping,” on page 203.
n
For multipathing to work properly, each LUN must present the same LUN ID number to all ESXi hosts.
n
Make sure the storage device driver specifies a large enough queue. You can set the queue depth for the
physical HBA during system setup. For information on changing queue depth for HBAs and virtual
machines, see the vSphere Troubleshooting documentation.
n
On virtual machines running Microsoft Windows, increase the value of the SCSI TimeoutValue
parameter to 60. This increase allows Windows to better tolerate delayed I/O resulting from path
failover. For information, see “Set Timeout on Windows Guest OS,” on page 185.
ESXi Fibre Channel SAN Restrictions
When you use ESXi with a SAN, certain restrictions apply.
n
ESXi does not support FC connected tape devices.
n
You cannot use multipathing software inside a virtual machine to perform I/O load balancing to a single
physical LUN. However, when your Microsoft Windows virtual machine uses dynamic disks, this
restriction does not apply. For information about configuring dynamic disks, see “Set Up Dynamic Disk
Mirroring,” on page 173.
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Setting LUN Allocations
This topic provides general information about how to allocate LUNs when your ESXi works in conjunction
with SAN.
When you set LUN allocations, be aware of the following points:
Storage provisioning
To ensure that the ESXi system recognizes the LUNs at startup time,
provision all LUNs to the appropriate HBAs before you connect the SAN to
the ESXi system.
VMware recommends that you provision all LUNs to all ESXi HBAs at the
same time. HBA failover works only if all HBAs see the same LUNs.
For LUNs that will be shared among multiple hosts, make sure that LUN IDs
are consistent across all hosts. For example, LUN 5 should be mapped to host
1, host 2, and host 3 as LUN 5.
vMotion and VMware
DRS
When you use vCenter Server and vMotion or DRS, make sure that the LUNs
for the virtual machines are provisioned to all ESXi hosts. This provides the
most ability to move virtual machines.
Active-active compared
to active-passive arrays
When you use vMotion or DRS with an active-passive SAN storage device,
make sure that all ESXi systems have consistent paths to all storage
processors. Not doing so can cause path thrashing when a vMotion
migration occurs.
For active-passive storage arrays not listed in Storage/SAN Compatibility,
VMware does not support storage port failover. In those cases, you must
connect the server to the active port on the storage array. This configuration
ensures that the LUNs are presented to the ESXi host.
Setting Fibre Channel HBAs
Typically, FC HBAs that you use on your ESXi host work correctly with the default configuration settings.
You should follow the configuration guidelines provided by your storage array vendor. During FC HBA
setup, consider the following issues.
n
Do not mix FC HBAs from different vendors in a single host. Having different models of the same HBA
is supported, but a single LUN cannot be accessed through two different HBA types, only through the
same type.
n
Ensure that the firmware level on each HBA is the same.
n
Set the timeout value for detecting a failover. To ensure optimal performance, do not change the default
value.
n
ESXi supports 16 GB end-to-end Fibre Channel connectivity.
Installation and Setup Steps
This topic provides an overview of installation and setup steps that you need to follow when configuring
your SAN environment to work with ESXi.
Follow these steps to configure your ESXi SAN environment.
40
1
Design your SAN if it is not already configured. Most existing SANs require only minor modification to
work with ESXi.
2
Check that all SAN components meet requirements.
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Chapter 4 Configuring Fibre Channel Storage
3
Perform any necessary storage array modification.
Most vendors have vendor-specific documentation for setting up a SAN to work with VMware ESXi.
4
Set up the HBAs for the hosts you have connected to the SAN.
5
Install ESXi on the hosts.
6
Create virtual machines and install guest operating systems.
7
(Optional) Set up your system for VMware HA failover or for using Microsoft Clustering Services.
8
Upgrade or modify your environment as needed.
N-Port ID Virtualization
N-Port ID Virtualization (NPIV) is an ANSI T11 standard that describes how a single Fibre Channel HBA
port can register with the fabric using several worldwide port names (WWPNs). This allows a fabricattached N-port to claim multiple fabric addresses. Each address appears as a unique entity on the Fibre
Channel fabric.
How NPIV-Based LUN Access Works
NPIV enables a single FC HBA port to register several unique WWNs with the fabric, each of which can be
assigned to an individual virtual machine.
SAN objects, such as switches, HBAs, storage devices, or virtual machines can be assigned World Wide
Name (WWN) identifiers. WWNs uniquely identify such objects in the Fibre Channel fabric. When virtual
machines have WWN assignments, they use them for all RDM traffic, so the LUNs pointed to by any of the
RDMs on the virtual machine must not be masked against its WWNs. When virtual machines do not have
WWN assignments, they access storage LUNs with the WWNs of their host’s physical HBAs. By using
NPIV, however, a SAN administrator can monitor and route storage access on a per virtual machine basis.
The following section describes how this works.
When a virtual machine has a WWN assigned to it, the virtual machine’s configuration file (.vmx) is updated
to include a WWN pair (consisting of a World Wide Port Name, WWPN, and a World Wide Node Name,
WWNN). As that virtual machine is powered on, the VMkernel instantiates a virtual port (VPORT) on the
physical HBA which is used to access the LUN. The VPORT is a virtual HBA that appears to the FC fabric as
a physical HBA, that is, it has its own unique identifier, the WWN pair that was assigned to the virtual
machine. Each VPORT is specific to the virtual machine, and the VPORT is destroyed on the host and it no
longer appears to the FC fabric when the virtual machine is powered off. When a virtual machine is
migrated from one host to another, the VPORT is closed on the first host and opened on the destination host.
If NPIV is enabled, WWN pairs (WWPN & WWNN) are specified for each virtual machine at creation time.
When a virtual machine using NPIV is powered on, it uses each of these WWN pairs in sequence to try to
discover an access path to the storage. The number of VPORTs that are instantiated equals the number of
physical HBAs present on the host. A VPORT is created on each physical HBA that a physical path is found
on. Each physical path is used to determine the virtual path that will be used to access the LUN. Note that
HBAs that are not NPIV-aware are skipped in this discovery process because VPORTs cannot be instantiated
on them.
Requirements for Using NPIV
If you plan to enable NPIV on your virtual machines, you should be aware of certain requirements.
The following requirements exist:
n
NPIV can be used only for virtual machines with RDM disks. Virtual machines with regular virtual
disks use the WWNs of the host’s physical HBAs.
n
HBAs on your host must support NPIV.
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For information, see the VMware Compatibility Guide and refer to your vendor documentation.
n
Use HBAs of the same type, either all QLogic or all Emulex. VMware does not support
heterogeneous HBAs on the same host accessing the same LUNs.
n
If a host uses multiple physical HBAs as paths to the storage, zone all physical paths to the virtual
machine. This is required to support multipathing even though only one path at a time will be
active.
n
Make sure that physical HBAs on the host have access to all LUNs that are to be accessed by NPIVenabled virtual machines running on that host.
n
The switches in the fabric must be NPIV-aware.
n
When configuring a LUN for NPIV access at the storage level, make sure that the NPIV LUN number
and NPIV target ID match the physical LUN and Target ID.
NPIV Capabilities and Limitations
Learn about specific capabilities and limitations of the use of NPIV with ESXi.
ESXi with NPIV supports the following items:
n
NPIV supports vMotion. When you use vMotion to migrate a virtual machine it retains the assigned
WWN.
If you migrate an NPIV-enabled virtual machine to a host that does not support NPIV, VMkernel reverts
to using a physical HBA to route the I/O.
n
If your FC SAN environment supports concurrent I/O on the disks from an active-active array, the
concurrent I/O to two different NPIV ports is also supported.
When you use ESXi with NPIV, the following limitations apply:
n
Because the NPIV technology is an extension to the FC protocol, it requires an FC switch and does not
work on the direct attached FC disks.
n
When you clone a virtual machine or template with a WWN assigned to it, the clones do not retain the
WWN.
n
NPIV does not support Storage vMotion.
n
Disabling and then re-enabling the NPIV capability on an FC switch while virtual machines are running
can cause an FC link to fail and I/O to stop.
Assign WWNs to Virtual Machines
Assign WWN settings to virtual machine with an RDM disk.
You can create from 1 to 16 WWN pairs, which can be mapped to the first 1 to 16 physical FC HBAs on the
host.
Prerequisites
Create a virtual machine with an RDM disk. See “Create Virtual Machines with RDMs,” on page 208.
Procedure
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1
In the vSphere Web Client, browse to the virtual machine.
2
Right-click the virtual machine and select Edit Settings.
3
Click VM Options.
4
Click the Fibre Channel NPIV triangle to expand the NPIV options.
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Chapter 4 Configuring Fibre Channel Storage
5
Deselect the Temporarily Disable NPIV for this virtual machine check box.
6
Select Generate new WWNs.
7
Specify the number of WWNNs and WWPNs.
A minimum of 2 WWPNs are needed to support failover with NPIV. Typically only 1 WWNN is created
for each virtual machine.
The host creates WWN assignments for the virtual machine.
What to do next
Register newly created WWNs in the fabric so that the virtual machine is able to log in to the switch, and
assign storage LUNs to the WWNs.
Modify WWN Assignments
You can modify WWN assignments for a virtual machine with an RDM.
Typically, you do not need to change existing WWN assignments on your virtual machine. In certain
circumstances, for example, when manually assigned WWNs are causing conflicts on the SAN, you might
need to change or remove WWNs.
Prerequisites
Make sure to power off the virtual machine if you want to edit the existing WWNs.
Before you begin, ensure that your SAN administrator has provisioned the storage LUN ACL to allow the
virtual machine’s ESXi host to access it.
Procedure
1
Open the Virtual Machine Properties dialog box by clicking the Edit Settings link for the selected
virtual machine.
2
Click the Options tab and select Fibre Channel NPIV.
The Virtual Machine Properties dialog box opens.
3
4
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Edit the WWN assignments by selecting one of the following options:
Option
Description
Temporarily disable NPIV for this
virtual machine
Disable the WWN assignments for the virtual machine.
Leave unchanged
The existing WWN assignments are retained. The read-only WWN
Assignments section of this dialog box displays the node and port values
of any existing WWN assignments.
Generate new WWNs
New WWNs are generated and assigned to the virtual machine,
overwriting any existing WWNs (those of the HBA itself are unaffected).
Remove WWN assignment
The WWNs assigned to the virtual machine are removed and it uses the
HBA WWNs to access the storage LUN. This option is not available if you
are creating a new virtual machine.
Click OK to save your changes.
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Configuring Fibre Channel over
Ethernet
5
To access Fibre Channel storage, an ESXi host can use the Fibre Channel over Ethernet (FCoE) protocol.
The FCoE protocol encapsulates Fibre Channel frames into Ethernet frames. As a result, your host does not
need special Fibre Channel links to connect to Fibre Channel storage, but can use 10Gbit lossless Ethernet to
deliver Fibre Channel traffic.
This chapter includes the following topics:
n
“Fibre Channel over Ethernet Adapters,” on page 45
n
“Configuration Guidelines for Software FCoE,” on page 46
n
“Set Up Networking for Software FCoE,” on page 46
n
“Add Software FCoE Adapters,” on page 47
Fibre Channel over Ethernet Adapters
To use Fibre Channel over Ethernet (FCoE), you need to install FCoE adapters on your host.
The adapters that VMware supports generally fall into two categories, hardware FCoE adapters and
software FCoE adapters that use the native FCoE stack in ESXi.
Hardware FCoE Adapters
This category includes completely offloaded specialized Converged Network Adapters (CNAs) that contain
network and Fibre Channel functionalities on the same card.
When such adapter is installed, your host detects and can use both CNA components. In the client, the
networking component appears as a standard network adapter (vmnic) and the Fibre Channel component
as a FCoE adapter (vmhba). You do not need to configure the hardware FCoE adapter to be able to use it.
Software FCoE Adapters
A software FCoE adapter uses the native FCoE protocol stack in ESXi for the protocol processing. The
software FCoE adapter is used with a NIC that offers Data Center Bridging (DCB) and I/O offload
capabilities. Intel X520 is an example of such NIC. For information on NICs supporting software FCoE, see
the VMware Compatibility Guide.
For the software FCoE adapter, you must properly configure networking and then activate the adapter.
Note The number of software FCoE adapters you activate corresponds to the number of physical NIC
ports. ESXi supports a maximum of four software FCoE adapters on one host.
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Configuration Guidelines for Software FCoE
When setting up your network environment to work with ESXi software FCoE, follow the guidelines and
best practices that VMware offers.
Network Switch Guidelines
Follow these guidelines when you configure a network switch for software FCoE environment:
n
On the ports that communicate with your ESXi host, disable the Spanning Tree Protocol (STP). Having
the STP enabled might delay the FCoE Initialization Protocol (FIP) response at the switch and cause an
all paths down (APD) condition.
The FIP is a protocol that FCoE uses to discover and initialize FCoE entities on the Ethernet.
n
Turn on Priority-based Flow Control (PFC) and set it to AUTO.
n
Make sure that you have a compatible firmware version on the FCoE switch.
Network Adapter Best Practices
If you plan to enable software FCoE adapters to work with network adapters, specific considerations apply.
n
Make sure that the latest microcode is installed on the FCoE network adapter.
n
If the network adapter has multiple ports, when configuring networking, add each port to a separate
vSwitch. This practice helps you to avoid an APD condition when a disruptive event, such as an MTU
change, occurs.
n
Do not move a network adapter port from one vSwitch to another when FCoE traffic is active. If you
need to make this change, reboot your host afterwards.
n
If you changed the vSwitch for a network adapter port and caused a failure, moving the port back to the
original vSwitch resolves the problem.
Set Up Networking for Software FCoE
Before you activate the software FCoE adapters, you need to create VMkernel network adapters for all
physical FCoE NICs installed on your host.
This procedure explains how to create a single VMkernel network adapter connected to a single FCoE
physical network adapter through a vSphere standard switch. If your host has multiple network adapters or
multiple ports on the adapter, connect each FCoE NIC to a separate standard switch. For more information,
see the vSphere Networking documentation.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click Actions > Add Networking.
3
Select VMkernel Network Adapter, and click Next.
4
Select New standard switch to create a vSphere standard switch.
5
Under Unclaimed Adapters, select the network adapter (vmnic#) that supports FCoE and click Assign.
Make sure to assign the adapter to Active Adapters.
6
Enter a network label.
Network label is a friendly name that identifies the VMkernel adapter that you are creating, for
example, FCoE.
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Chapter 5 Configuring Fibre Channel over Ethernet
7
Specify a VLAN ID and click Next.
Because FCoE traffic requires an isolated network, make sure that the VLAN ID you enter is different
from the one used for regular networking on your host. For more information, see the vSphere
Networking documentation.
8
After completing configuration, review the information and click Finish.
You have created the virtual VMkernel adapter for the physical FCoE network adapter installed on your
host.
Note To avoid FCoE traffic disruptions, do not remove the FCoE network adapter (vmnic#) from the
vSphere standard switch after you set up FCoE networking.
Add Software FCoE Adapters
You must activate software FCoE adapters so that your host can use them to access Fibre Channel storage.
The number of software FCoE adapters you can activate corresponds to the number of physical FCoE NIC
ports on your host. ESXi supports the maximum of four software FCoE adapters on one host.
Prerequisites
Set up networking for the software FCoE adapter.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and click the Add icon (
4
Select Software FCoE Adapter.
5
On the Add Software FCoE Adapter dialog box, select an appropriate vmnic from the drop-down list of
physical network adapters.
).
Only those adapters that are not yet used for FCoE traffic are listed.
6
Click OK.
The software FCoE adapter appears on the list of storage adapters.
After you activate the software FCoE adapter, you can view its properties. If you do not use the adapter, you
can remove it from the list of adapters.
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Booting ESXi from Fibre Channel
SAN
6
When you set up your host to boot from a SAN, your host's boot image is stored on one or more LUNs in
the SAN storage system. When the host starts, it boots from the LUN on the SAN rather than from its local
disk.
ESXi supports booting through a Fibre Channel host bus adapter (HBA) or a Fibre Channel over Ethernet
(FCoE) converged network adapter (CNA).
This chapter includes the following topics:
n
“Boot from SAN Benefits,” on page 49
n
“Boot from Fibre Channel SAN Requirements and Considerations,” on page 50
n
“Getting Ready for Boot from SAN,” on page 50
n
“Configure Emulex HBA to Boot from SAN,” on page 52
n
“Configure QLogic HBA to Boot from SAN,” on page 53
Boot from SAN Benefits
Boot from SAN can provide numerous benefits to your environment. However, in certain cases, you should
not use boot from SAN for ESXi hosts. Before you set up your system for boot from SAN, decide whether it
is appropriate for your environment.
Caution When you use boot from SAN with multiple ESXi hosts, each host must have its own boot LUN.
If you configure multiple hosts to share the same boot LUN, ESXi image corruption is likely to occur.
If you use boot from SAN, the benefits for your environment will include the following:
n
Cheaper servers. Servers can be more dense and run cooler without internal storage.
n
Easier server replacement. You can replace servers and have the new server point to the old boot
location.
n
Less wasted space. Servers without local disks often take up less space.
n
Easier backup processes. You can backup the system boot images in the SAN as part of the overall SAN
backup procedures. Also, you can use advanced array features such as snapshots on the boot image.
n
Improved management. Creating and managing the operating system image is easier and more
efficient.
n
Better reliability. You can access the boot disk through multiple paths, which protects the disk from
being a single point of failure.
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Boot from Fibre Channel SAN Requirements and Considerations
Your ESXi boot configuration must meet specific requirements.
Table 6‑1. Boot from SAN Requirements
Requirement
Description
ESXi system
requirements
Follow vendor recommendation for the server booting from a SAN.
Adapter
requirements
Enable and correctly configure the adapter, so it can access the boot LUN. See your vendor
documentation.
Access control
n
n
Each host must have access to its own boot LUN only, not the boot LUNs of other hosts. Use
storage system software to make sure that the host accesses only the designated LUNs.
Multiple servers can share a diagnostic partition. You can use array specific LUN masking to
achieve this.
Multipathing
support
Multipathing to a boot LUN on active-passive arrays is not supported because the BIOS does not
support multipathing and is unable to activate a standby path.
SAN considerations
SAN connections must be through a switched topology if the array is not certified for direct
connect topology. If the array is certified for direct connect topology, the SAN connections can be
made directly to the array. Boot from SAN is supported for both switched topology and direct
connect topology if these topologies for the specific array are certified.
Hardware- specific
considerations
If you are running an IBM eServer BladeCenter and use boot from SAN, you must disable IDE
drives on the blades.
Getting Ready for Boot from SAN
When you set up your boot from SAN environment, you perform a number of tasks.
This section describes the generic boot-from-SAN enablement process on the rack mounted servers. For
information on enabling boot from SAN on Cisco Unified Computing System FCoE blade servers, refer to
Cisco documentation.
1
Configure SAN Components and Storage System on page 50
Before you set up your ESXi host to boot from a SAN LUN, configure SAN components and a storage
system.
2
Configure Storage Adapter to Boot from SAN on page 51
When you set up your host to boot from SAN, you enable the boot adapter in the host BIOS. You then
configure the boot adapter to initiate a primitive connection to the target boot LUN.
3
Set Up Your System to Boot from Installation Media on page 51
When setting up your host to boot from SAN, you first boot the host from the VMware installation
media. To achieve this, you need to change the system boot sequence in the BIOS setup.
Configure SAN Components and Storage System
Before you set up your ESXi host to boot from a SAN LUN, configure SAN components and a storage
system.
Because configuring the SAN components is vendor specific, refer to the product documentation for each
item.
Procedure
1
Connect network cable, referring to any cabling guide that applies to your setup.
Check the switch wiring, if there is any.
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Chapter 6 Booting ESXi from Fibre Channel SAN
2
Configure the storage array.
a
From the SAN storage array, make the ESXi host visible to the SAN. This process is often referred
to as creating an object.
b
From the SAN storage array, set up the host to have the WWPNs of the host’s adapters as port
names or node names.
c
Create LUNs.
d
Assign LUNs.
e
Record the IP addresses of the switches and storage arrays.
f
Record the WWPN for each SP.
Caution If you use scripted installation to install ESXi in boot from SAN mode, you need to take
special steps to avoid unintended data loss.
Configure Storage Adapter to Boot from SAN
When you set up your host to boot from SAN, you enable the boot adapter in the host BIOS. You then
configure the boot adapter to initiate a primitive connection to the target boot LUN.
Prerequisites
Determine the WWPN for the storage adapter.
Procedure
u
Configure the storage adapter to boot from SAN.
Because configuring boot adapters is vendor specific, refer to your vendor documentation.
Set Up Your System to Boot from Installation Media
When setting up your host to boot from SAN, you first boot the host from the VMware installation media.
To achieve this, you need to change the system boot sequence in the BIOS setup.
Because changing the boot sequence in the BIOS is vendor specific, refer to vendor documentation for
instructions. The following procedure explains how to change the boot sequence on an IBM host.
Procedure
1
During your system power up, enter the system BIOS Configuration/Setup Utility.
2
Select Startup Options and press Enter.
3
Select Startup Sequence Options and press Enter.
4
Change the First Startup Device to [CD-ROM].
You can now install ESXi.
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Configure Emulex HBA to Boot from SAN
Configuring the Emulex HBA BIOS to boot from SAN includes enabling the BootBIOS prompt and enabling
BIOS.
Procedure
1
Enable the BootBIOS Prompt on page 52
When you configure the Emulex HBA BIOS to boot ESXi from SAN, you need to enable the BootBIOS
prompt.
2
Enable the BIOS on page 52
When you configure the Emulex HBA BIOS to boot ESXi from SAN, you need to enable BIOS.
Enable the BootBIOS Prompt
When you configure the Emulex HBA BIOS to boot ESXi from SAN, you need to enable the BootBIOS
prompt.
Procedure
1
Run lputil.
2
Select 3. Firmware Maintenance.
3
Select an adapter.
4
Select 6. Boot BIOS Maintenance.
5
Select 1. Enable Boot BIOS.
Enable the BIOS
When you configure the Emulex HBA BIOS to boot ESXi from SAN, you need to enable BIOS.
Procedure
1
Reboot the host.
2
To configure the adapter parameters, press ALT+E at the Emulex prompt and follow these steps.
3
52
a
Select an adapter (with BIOS support).
b
Select 2. Configure This Adapter's Parameters.
c
Select 1. Enable or Disable BIOS.
d
Select 1 to enable BIOS.
e
Select x to exit and Esc to return to the previous menu.
To configure the boot device, follow these steps from the Emulex main menu.
a
Select the same adapter.
b
Select 1. Configure Boot Devices.
c
Select the location for the Boot Entry.
d
Enter the two-digit boot device.
e
Enter the two-digit (HEX) starting LUN (for example, 08).
f
Select the boot LUN.
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Chapter 6 Booting ESXi from Fibre Channel SAN
g
Select 1. WWPN. (Boot this device using WWPN, not DID).
h
Select x to exit and Y to reboot.
4
Boot into the system BIOS and move Emulex first in the boot controller sequence.
5
Reboot and install on a SAN LUN.
Configure QLogic HBA to Boot from SAN
This sample procedure explains how to configure the QLogic HBA to boot ESXi from SAN. The procedure
involves enabling the QLogic HBA BIOS, enabling the selectable boot, and selecting the boot LUN.
Procedure
1
While booting the server, press Ctrl+Q to enter the Fast!UTIL configuration utility.
2
Perform the appropriate action depending on the number of HBAs.
Option
Description
One HBA
If you have only one host bus adapter (HBA), the Fast!UTIL Options page
appears. Skip to Step 3.
Multiple HBAs
If you have more than one HBA, select the HBA manually.
a In the Select Host Adapter page, use the arrow keys to position the
cursor on the appropriate HBA.
b Press Enter.
3
In the Fast!UTIL Options page, select Configuration Settings and press Enter.
4
In the Configuration Settings page, select Adapter Settings and press Enter.
5
Set the BIOS to search for SCSI devices.
6
a
In the Host Adapter Settings page, select Host Adapter BIOS.
b
Press Enter to toggle the value to Enabled.
c
Press Esc to exit.
Enable the selectable boot.
a
Select Selectable Boot Settings and press Enter.
b
In the Selectable Boot Settings page, select Selectable Boot.
c
Press Enter to toggle the value to Enabled.
7
Use the cursor keys to select the Boot Port Name entry in the list of storage processors (SPs) and press
Enter to open the Select Fibre Channel Device screen.
8
Use the cursor keys to select the specific SP and press Enter.
If you are using an active-passive storage array, the selected SP must be on the preferred (active) path to
the boot LUN. If you are not sure which SP is on the active path, use your storage array management
software to find out. The target IDs are created by the BIOS and might change with each reboot.
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Perform the appropriate action depending on the number of LUNs attached to the SP.
Option
Description
One LUN
The LUN is selected as the boot LUN. You do not need to enter the Select
LUN screen.
Multiple LUNs
Select LUN screen opens. Use the cursor to select the boot LUN, then press
Enter.
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54
10
If any remaining storage processors show in the list, press C to clear the data.
11
Press Esc twice to exit and press Enter to save the setting.
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Booting ESXi with Software FCoE
7
ESXi supports boot from FCoE capable network adapters.
When you install and boot ESXi from an FCoE LUN, the host can use a VMware software FCoE adapter and
a network adapter with FCoE capabilities. The host does not require a dedicated FCoE HBA.
You perform most configurations through the option ROM of your network adapter. The network adapters
must support one of the following formats, which communicate parameters about an FCoE boot device to
VMkernel.
n
FCoE Boot Firmware Table (FBFT). FBFT is Intel propriety.
n
FCoE Boot Parameter Table (FBPT). FBPT is defined by VMware for third-party vendors to implement
software FCoE boot.
The configuration parameters are set in the option ROM of your adapter. During an ESXi installation or a
subsequent boot, these parameters are exported in to system memory in either FBFT format or FBPT format.
The VMkernel can read the configuration settings and use them to access the boot LUN.
This chapter includes the following topics:
n
“Requirements and Considerations for Software FCoE Boot,” on page 55
n
“Best Practices for Software FCoE Boot,” on page 56
n
“Set Up Software FCoE Boot,” on page 56
n
“Troubleshooting Installation and Boot from Software FCoE,” on page 57
Requirements and Considerations for Software FCoE Boot
When you boot the ESXi host from SAN using software FCoE, certain requirements and considerations
apply.
Requirements
n
ESXi 5.1 or later.
n
The network adapter must have the following capabilities:
n
Be FCoE capable.
n
Support ESXi open FCoE stack.
n
Contain FCoE boot firmware which can export boot information in FBFT format or FBPT format.
Considerations
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You cannot change software FCoE boot configuration from within ESXi.
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n
Coredump is not supported on any software FCoE LUNs, including the boot LUN.
n
Multipathing is not supported at pre-boot.
n
Boot LUN cannot be shared with other hosts even on shared storage.
Best Practices for Software FCoE Boot
VMware recommends several best practices when you boot your system from a software FCoE LUN.
n
Make sure that the host has access to the entire boot LUN. The boot LUN cannot be shared with other
hosts even on shared storage.
n
If you use Intel 10 Gigabit Ethernet Controller (Niantec) with a Cisco switch, configure the switch port
in the following way:
n
Enable the Spanning Tree Protocol (STP).
n
Turn off switchport trunk native vlan for the VLAN used for FCoE.
Set Up Software FCoE Boot
Your ESXi host can boot from a FCoE LUN using the software FCoE adapter a network adapter.
When you configure your host for a software FCoE boot, you perform a number of tasks.
Prerequisites
The network adapter has the following capabilities:
n
Support partial FCoE offload (software FCoE).
n
Contain either a FCoE Boot Firmware Table (FBFT) or a FCoE Boot Parameter Table (FBPT).
For information about network adapters that support software FCoE boot, see the VMware Compatibility
Guide.
Procedure
1
Configure Software FCoE Boot Parameters on page 56
To support a software FCoE boot process, a network adapter on your host must have a specially
configured FCoE boot firmware. When you configure the firmware, you enable the adapter for the
software FCoE boot and specify the boot LUN parameters.
2
Install and Boot ESXi from Software FCoE LUN on page 57
When you set up your system to boot from a software FCoE LUN, you install the ESXi image to the
target LUN. You can then boot your host from that LUN.
Configure Software FCoE Boot Parameters
To support a software FCoE boot process, a network adapter on your host must have a specially configured
FCoE boot firmware. When you configure the firmware, you enable the adapter for the software FCoE boot
and specify the boot LUN parameters.
Procedure
u
In the option ROM of the network adapter, specify software FCoE boot parameters.
These parameters include boot target, boot LUN, VLAN ID, and so on.
Because configuring the network adapter is vendor specific, review your vendor documentation for
instructions.
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Chapter 7 Booting ESXi with Software FCoE
Install and Boot ESXi from Software FCoE LUN
When you set up your system to boot from a software FCoE LUN, you install the ESXi image to the target
LUN. You can then boot your host from that LUN.
Prerequisites
n
Configure the option ROM of the network adapter to point to a target LUN that you want to use as the
boot LUN. Make sure that you have information about the bootable LUN.
n
Change the boot order in the system BIOS to the following sequence:
a
The network adapter that you use for the software FCoE boot.
b
The ESXi installation media.
See the vendor documentation for your system.
Procedure
1
Start an interactive installation from the ESXi installation CD/DVD.
The ESXi installer verifies that FCoE boot is enabled in the BIOS and, if needed, creates a standard
virtual switch for the FCoE capable network adapter. The name of the vSwitch is
VMware_FCoE_vSwitch. The installer then uses preconfigured FCoE boot parameters to discover and
display all available FCoE LUNs.
2
On the Select a Disk screen, select the software FCoE LUN that you specified in the boot parameter
setting.
If the boot LUN does not appear in this menu, make sure that you correctly configured boot parameters
in the option ROM of the network adapter.
3
Follow the prompts to complete the installation.
4
Reboot the host.
5
Change the boot order in the system BIOS so that the FCoE boot LUN is the first bootable device.
ESXi continues booting from the software FCoE LUN until it is ready to be used.
What to do next
If needed, you can rename and modify the VMware_FCoE_vSwitch that the installer automatically created.
Make sure that the Cisco Discovery Protocol (CDP) mode is set to Listen or Both.
Troubleshooting Installation and Boot from Software FCoE
If the installation or boot of ESXi from a software FCoE LUN fails, you can use several troubleshooting
methods.
Problem
When you install or boot ESXi from FCoE storage using a VMware software FCoE adapter and a network
adapter with partial FCoE offload capabilities, the installation or the boot process fails.
Solution
n
Make sure that you correctly configured boot parameters in the option ROM of the FCoE network
adapter.
n
During installation, monitor the BIOS of the FCoE network adapter for any errors.
n
If possible, check the VMkernel log for errors.
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n
Use the esxcli command to verify whether the boot LUN is present.
esxcli conn_options hardware bootdevice list
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Best Practices for Fibre Channel
Storage
8
When using ESXi with Fibre Channel SAN, follow best practices that VMware offers to avoid performance
problems.
The vSphere Web Client offer extensive facilities for collecting performance information. The information is
graphically displayed and frequently updated.
You can also use the resxtop or esxtop command-line utilities. The utilities provide a detailed look at how
ESXi uses resources in real time. For more information, see the vSphere Resource Management documentation.
Check with your storage representative if your storage system supports Storage API - Array Integration
hardware acceleration features. If it does, refer to your vendor documentation for information on how to
enable hardware acceleration support on the storage system side. For more information, see Chapter 23,
“Storage Hardware Acceleration,” on page 277.
This chapter includes the following topics:
n
“Preventing Fibre Channel SAN Problems,” on page 59
n
“Disable Automatic Host Registration,” on page 60
n
“Optimizing Fibre Channel SAN Storage Performance,” on page 60
Preventing Fibre Channel SAN Problems
When using ESXi in conjunction with a Fibre Channel SAN, you must follow specific guidelines to avoid
SAN problems.
You should observe these tips for preventing problems with your SAN configuration:
n
Place only one VMFS datastore on each LUN.
n
Do not change the path policy the system sets for you unless you understand the implications of
making such a change.
n
Document everything. Include information about zoning, access control, storage, switch, server and FC
HBA configuration, software and firmware versions, and storage cable plan.
n
Plan for failure:
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n
Make several copies of your topology maps. For each element, consider what happens to your SAN
if the element fails.
n
Cross off different links, switches, HBAs and other elements to ensure you did not miss a critical
failure point in your design.
Ensure that the Fibre Channel HBAs are installed in the correct slots in the host, based on slot and bus
speed. Balance PCI bus load among the available busses in the server.
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n
Become familiar with the various monitor points in your storage network, at all visibility points,
including host's performance charts, FC switch statistics, and storage performance statistics.
n
Be cautious when changing IDs of the LUNs that have VMFS datastores being used by your ESXi host.
If you change the ID, the datastore becomes inactive and its virtual machines fail. You can resignature
the datastore to make it active again. See “Managing Duplicate VMFS Datastores,” on page 163.
If there are no running virtual machines on the VMFS datastore, after you change the ID of the LUN,
you must use rescan to reset the ID on your host. For information on using rescan, see “Storage Rescan
Operations,” on page 120.
Disable Automatic Host Registration
Certain storage arrays require that ESXi hosts register with the arrays. ESXi performs automatic host
registration by sending the host's name and IP address to the array. If you prefer to perform manual
registration using storage management software, disable the ESXi auto-registration feature.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
Under Advanced System Settings, select the Disk.EnableNaviReg parameter and click the Edit icon.
5
Change the value to 0.
This operation disables the automatic host registration that is enabled by default.
Optimizing Fibre Channel SAN Storage Performance
Several factors contribute to optimizing a typical SAN environment.
If the environment is properly configured, the SAN fabric components (particularly the SAN switches) are
only minor contributors because of their low latencies relative to servers and storage arrays. Make sure that
the paths through the switch fabric are not saturated, that is, that the switch fabric is running at the highest
throughput.
Storage Array Performance
Storage array performance is one of the major factors contributing to the performance of the entire SAN
environment.
If there are issues with storage array performance, be sure to consult your storage array vendor’s
documentation for any relevant information.
Follow these general guidelines to improve the array performance in the vSphere environment:
60
n
When assigning LUNs, remember that each LUN is accessed by a number of hosts, and that a number
of virtual machines can run on each host. One LUN used by a host can service I/O from many different
applications running on different operating systems. Because of this diverse workload, the RAID group
containing the ESXi LUNs should not include LUNs used by other servers that are not running ESXi.
n
Make sure read/write caching is enabled.
n
SAN storage arrays require continual redesign and tuning to ensure that I/O is load balanced across all
storage array paths. To meet this requirement, distribute the paths to the LUNs among all the SPs to
provide optimal load balancing. Close monitoring indicates when it is necessary to rebalance the LUN
distribution.
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Chapter 8 Best Practices for Fibre Channel Storage
Tuning statically balanced storage arrays is a matter of monitoring the specific performance statistics
(such as I/O operations per second, blocks per second, and response time) and distributing the LUN
workload to spread the workload across all the SPs.
Note Dynamic load balancing is not currently supported with ESXi.
Server Performance with Fibre Channel
You must consider several factors to ensure optimal server performance.
Each server application must have access to its designated storage with the following conditions:
n
High I/O rate (number of I/O operations per second)
n
High throughput (megabytes per second)
n
Minimal latency (response times)
Because each application has different requirements, you can meet these goals by choosing an appropriate
RAID group on the storage array. To achieve performance goals:
n
Place each LUN on a RAID group that provides the necessary performance levels. Pay attention to the
activities and resource utilization of other LUNS in the assigned RAID group. A high-performance
RAID group that has too many applications doing I/O to it might not meet performance goals required
by an application running on the ESXi host.
n
Make sure that each server has a sufficient number of HBAs to allow maximum throughput for all the
applications hosted on the server for the peak period. I/O spread across multiple HBAs provide higher
throughput and less latency for each application.
n
To provide redundancy in the event of HBA failure, make sure the server is connected to a dual
redundant fabric.
n
When allocating LUNs or RAID groups for ESXi systems, multiple operating systems use and share that
resource. As a result, the performance required from each LUN in the storage subsystem can be much
higher if you are working with ESXi systems than if you are using physical machines. For example, if
you expect to run four I/O intensive applications, allocate four times the performance capacity for the
ESXi LUNs.
n
When using multiple ESXi systems in conjunction with vCenter Server, the performance needed from
the storage subsystem increases correspondingly.
n
The number of outstanding I/Os needed by applications running on an ESXi system should match the
number of I/Os the HBA and storage array can handle.
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Using ESXi with iSCSI SAN
9
You can use ESXi in conjunction with a storage area network (SAN), a specialized high-speed network that
connects computer systems to high-performance storage subsystems. Using ESXi together with a SAN
provides storage consolidation, improves reliability, and helps with disaster recovery.
To use ESXi effectively with a SAN, you must have a working knowledge of ESXi systems and SAN
concepts. Also, when you set up ESXi hosts to use Internet SCSI (iSCSI) SAN storage systems, you must be
aware of certain special considerations that exist.
This chapter includes the following topics:
n
“iSCSI SAN Concepts,” on page 63
n
“How Virtual Machines Access Data on an iSCSI SAN,” on page 68
iSCSI SAN Concepts
If you are an administrator who plans to set up ESXi hosts to work with iSCSI SANs, you must have a
working knowledge of iSCSI concepts.
iSCSI SANs use Ethernet connections between computer systems, or host servers, and high performance
storage subsystems. The SAN components include iSCSI host bus adapters (HBAs) or Network Interface
Cards (NICs) in the host servers, switches and routers that transport the storage traffic, cables, storage
processors (SPs), and storage disk systems.
iSCSI SAN uses a client-server architecture. The client, called iSCSI initiator, operates on your host. It
initiates iSCSI sessions by issuing SCSI commands and transmitting them, encapsulated into iSCSI protocol,
to a server. The server is known as an iSCSI target. The iSCSI target represents a physical storage system on
the network. It can also be provided by a virtual iSCSI SAN, for example, an iSCSI target emulator running
in a virtual machine. The iSCSI target responds to the initiator's commands by transmitting required iSCSI
data.
iSCSI Multipathing
When transferring data between the host server and storage, the SAN uses a technique known as
multipathing. Multipathing allows you to have more than one physical path from the ESXi host to a LUN on
a storage system.
Generally, a single path from a host to a LUN consists of an iSCSI adapter or NIC, switch ports, connecting
cables, and the storage controller port. If any component of the path fails, the host selects another available
path for I/O. The process of detecting a failed path and switching to another is called path failover.
For more information on multipathing, see Chapter 17, “Understanding Multipathing and Failover,” on
page 181.
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Ports in the iSCSI SAN
A single discoverable entity on the iSCSI SAN, such as an initiator or a target, represents an iSCSI node.
Each node has one or more ports that connect it to the SAN.
iSCSI ports are end-points of an iSCSI session. Each node can be identified in a number of ways.
IP Address
Each iSCSI node can have an IP address associated with it so that routing
and switching equipment on your network can establish the connection
between the server and storage. This address is just like the IP address that
you assign to your computer to get access to your company's network or the
Internet.
iSCSI Name
A worldwide unique name for identifying the node. iSCSI uses the iSCSI
Qualified Name (IQN) and Extended Unique Identifier (EUI).
By default, ESXi generates unique iSCSI names for your iSCSI initiators, for
example, iqn.1998-01.com.vmware:iscsitestox-68158ef2. Usually, you do
not have to change the default value, but if you do, make sure that the new
iSCSI name you enter is worldwide unique.
iSCSI Alias
A more manageable name for an iSCSI device or port used instead of the
iSCSI name. iSCSI aliases are not unique and are intended to be just a
friendly name to associate with a port.
iSCSI Naming Conventions
iSCSI uses a special unique name to identify an iSCSI node, either target or initiator. This name is similar to
the WorldWide Name (WWN) associated with Fibre Channel devices and is used as a way to universally
identify the node.
iSCSI names are formatted in two different ways. The most common is the IQN format.
For more details on iSCSI naming requirements and string profiles, see RFC 3721 and RFC 3722 on the IETF
Web site.
iSCSI Qualified Name (IQN) Format
The IQN format takes the form iqn.yyyy-mm.naming-authority:unique name, where:
n
yyyy-mm is the year and month when the naming authority was established.
n
naming-authority is usually reverse syntax of the Internet domain name of the naming authority. For
example, the iscsi.vmware.com naming authority could have the iSCSI qualified name form of iqn.
1998-01.com.vmware.iscsi. The name indicates that the vmware.com domain name was registered in
January of 1998, and iscsi is a subdomain, maintained by vmware.com.
n
unique name is any name you want to use, for example, the name of your host. The naming authority
must make sure that any names assigned following the colon are unique, such as:
n
iqn.1998-01.com.vmware.iscsi:name1
n
iqn.1998-01.com.vmware.iscsi:name2
n
iqn.1998-01.com.vmware.iscsi:name999
Enterprise Unique Identifier (EUI) Format
The EUI format takes the form eui.16 hex digits.
For example, eui.0123456789ABCDEF.
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Chapter 9 Using ESXi with iSCSI SAN
The 16-hexadecimal digits are text representations of a 64-bit number of an IEEE EUI (extended unique
identifier) format. The top 24 bits are a company ID that IEEE registers with a particular company. The lower
40 bits are assigned by the entity holding that company ID and must be unique.
iSCSI Initiators
To access iSCSI targets, your host uses iSCSI initiators. The initiators transport SCSI requests and responses,
encapsulated into the iSCSI protocol, between the host and the iSCSI target.
Your host supports different types of initiators.
For information on configuring and using iSCSI adapters, see Chapter 10, “Configuring iSCSI Adapters and
Storage,” on page 69.
Software iSCSI Adapter
A software iSCSI adapter is a VMware code built into the VMkernel. It allows your host to connect to the
iSCSI storage device through standard network adapters. The software iSCSI adapter handles iSCSI
processing while communicating with the network adapter. With the software iSCSI adapter, you can use
iSCSI technology without purchasing specialized hardware.
Hardware iSCSI Adapter
A hardware iSCSI adapter is a third-party adapter that offloads iSCSI and network processing from your
host. Hardware iSCSI adapters are divided into categories.
Dependent Hardware
iSCSI Adapter
Depends on VMware networking, and iSCSI configuration and management
interfaces provided by VMware.
This type of adapter can be a card that presents a standard network adapter
and iSCSI offload functionality for the same port. The iSCSI offload
functionality depends on the host's network configuration to obtain the IP,
MAC, and other parameters used for iSCSI sessions. An example of a
dependent adapter is the iSCSI licensed Broadcom 5709 NIC.
Independent Hardware
iSCSI Adapter
Implements its own networking and iSCSI configuration and management
interfaces.
An example of an independent hardware iSCSI adapter is a card that either
presents only iSCSI offload functionality or iSCSI offload functionality and
standard NIC functionality. The iSCSI offload functionality has independent
configuration management that assigns the IP, MAC, and other parameters
used for the iSCSI sessions. An example of a independent adapter is the
QLogic QLA4052 adapter.
Hardware iSCSI adapters might need to be licensed. Otherwise, they will not appear in the client or vSphere
CLI. Contact your vendor for licensing information.
Establishing iSCSI Connections
In the ESXi context, the term target identifies a single storage unit that your host can access. The terms
storage device and LUN describe a logical volume that represents storage space on a target. Typically, the
terms device and LUN, in the ESXi context, mean a SCSI volume presented to your host from a storage
target and available for formatting.
Different iSCSI storage vendors present storage to servers in different ways. Some vendors present multiple
LUNs on a single target, while others present multiple targets with one LUN each. While the way the
storage is used by ESXi is similar, the way the information is presented through administrative tools is
different.
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Figure 9‑1. Target Compared to LUN Representations
target
LUN
LUN
LUN
target
target
target
LUN
LUN
LUN
storage array
storage array
Three LUNs are available in each of these configurations. In the first case, the host detects one target but that
target has three LUNs that can be used. Each of the LUNs represents individual storage volume. In the
second case, the host detects three different targets, each having one LUN.
Host-based iSCSI initiators establish connections to each target. Storage systems with a single target
containing multiple LUNs have traffic to all the LUNs on a single connection. With a system that has three
targets with one LUN each, a host uses separate connections to the three LUNs. This information is useful
when you are trying to aggregate storage traffic on multiple connections from the host with multiple iSCSI
HBAs, where traffic for one target can be set to a particular HBA, while traffic for another target can use a
different HBA.
iSCSI Storage System Types
ESXi supports different storage systems and arrays.
The types of storage that your host supports include active-active, active-passive, and ALUA-compliant.
Active-active storage
system
Supports access to the LUNs simultaneously through all the storage ports
that are available without significant performance degradation. All the paths
are always active, unless a path fails.
Active-passive storage
system
A system in which one storage processor is actively providing access to a
given LUN. The other processors act as a backup for the LUN and can be
actively providing access to other LUN I/O. I/O can be successfully sent only
to an active port for a given LUN. If access through the active storage port
fails, one of the passive storage processors can be activated by the servers
accessing it.
Asymmetrical storage
system
Supports Asymmetric Logical Unit Access (ALUA). ALUA-compliant
storage systems provide different levels of access per port. With ALUA, hosts
can determine the states of target ports and prioritize paths. The host uses
some of the active paths as primary and others as secondary.
Virtual port storage
system
Supports access to all available LUNs through a single virtual port. Virtual
port storage systems are active-active storage devices, but hide their multiple
connections though a single port. ESXi multipathing does not make multiple
connections from a specific port to the storage by default. Some storage
vendors supply session managers to establish and manage multiple
connections to their storage. These storage systems handle port failovers and
connection balancing transparently. This capability is often called transparent
failover.
Discovery, Authentication, and Access Control
You can use several mechanisms to discover your storage and to limit access to it.
You must configure your host and the iSCSI storage system to support your storage access control policy.
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Discovery
A discovery session is part of the iSCSI protocol, and it returns the set of targets you can access on an iSCSI
storage system. The two types of discovery available on ESXi are dynamic and static. Dynamic discovery
obtains a list of accessible targets from the iSCSI storage system, while static discovery can only try to access
one particular target by target name and address.
For more information, see “Configuring Discovery Addresses for iSCSI Adapters,” on page 93.
Authentication
iSCSI storage systems authenticate an initiator by a name and key pair. ESXi supports the CHAP protocol,
which VMware recommends for your SAN implementation. To use CHAP authentication, the ESXi host and
the iSCSI storage system must have CHAP enabled and have common credentials.
For information on enabling CHAP, see “Configuring CHAP Parameters for iSCSI Adapters,” on page 94.
Access Control
Access control is a policy set up on the iSCSI storage system. Most implementations support one or more of
three types of access control:
n
By initiator name
n
By IP address
n
By the CHAP protocol
Only initiators that meet all rules can access the iSCSI volume.
Using only CHAP for access control can slow down rescans because the ESXi host can discover all targets,
but then fails at the authentication step. iSCSI rescans work faster if the host discovers only the targets it can
authenticate.
Error Correction
To protect the integrity of iSCSI headers and data, the iSCSI protocol defines error correction methods
known as header digests and data digests.
Both parameters are disabled by default, but you can enable them. These digests pertain to, respectively, the
header and SCSI data being transferred between iSCSI initiators and targets, in both directions.
Header and data digests check the end-to-end, noncryptographic data integrity beyond the integrity checks
that other networking layers provide, such as TCP and Ethernet. They check the entire communication path,
including all elements that can change the network-level traffic, such as routers, switches, and proxies.
The existence and type of the digests are negotiated when an iSCSI connection is established. When the
initiator and target agree on a digest configuration, this digest must be used for all traffic between them.
Enabling header and data digests does require additional processing for both the initiator and the target and
can affect throughput and CPU use performance.
Note Systems that use Intel Nehalem processors offload the iSCSI digest calculations, thus reducing the
impact on performance.
For information on enabling header and data digests, see “Configuring Advanced Parameters for iSCSI,” on
page 98.
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How Virtual Machines Access Data on an iSCSI SAN
ESXi stores a virtual machine's disk files within a VMFS datastore that resides on a SAN storage device.
When virtual machine guest operating systems issue SCSI commands to their virtual disks, the SCSI
virtualization layer translates these commands to VMFS file operations.
When a virtual machine interacts with its virtual disk stored on a SAN, the following process takes place:
1
When the guest operating system in a virtual machine reads or writes to SCSI disk, it issues SCSI
commands to the virtual disk.
2
Device drivers in the virtual machine’s operating system communicate with the virtual SCSI controllers.
3
The virtual SCSI controller forwards the command to the VMkernel.
4
The VMkernel performs the following tasks.
5
6
7
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a
Locates the file, which corresponds to the guest virtual machine disk, in the VMFS volume.
b
Maps the requests for the blocks on the virtual disk to blocks on the appropriate physical device.
c
Sends the modified I/O request from the device driver in the VMkernel to the iSCSI initiator
(hardware or software).
If the iSCSI initiator is a hardware iSCSI adapter (both independent or dependent), the adapter
performs the following tasks.
a
Encapsulates I/O requests into iSCSI Protocol Data Units (PDUs).
b
Encapsulates iSCSI PDUs into TCP/IP packets.
c
Sends IP packets over Ethernet to the iSCSI storage system.
If the iSCSI initiator is a software iSCSI adapter, the following takes place.
a
The iSCSI initiator encapsulates I/O requests into iSCSI PDUs.
b
The initiator sends iSCSI PDUs through TCP/IP connections.
c
The VMkernel TCP/IP stack relays TCP/IP packets to a physical NIC.
d
The physical NIC sends IP packets over Ethernet to the iSCSI storage system.
Depending on which port the iSCSI initiator uses to connect to the network, Ethernet switches and
routers carry the request to the storage device that the host wants to access.
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Configuring iSCSI Adapters and
Storage
Before ESXi can work with a SAN, you must set up your iSCSI adapters and storage.
To do this, you must first observe certain basic requirements and then follow best practices for installing and
setting up hardware or software iSCSI adapters to access the SAN.
The following table lists the iSCSI adapters (vmhbas) that ESXi supports and indicates whether VMkernel
networking configuration is required.
Table 10‑1. Supported iSCSI adapters
iSCSI Adapter (vmhba)
Description
VMkernel Networking
Software
Uses standard NICs to connect your
host to a remote iSCSI target on the
IP network .
Required
Independent Hardware
Third-party adapter that offloads the
iSCSI and network processing and
management from your host.
Not required
Dependent Hardware
Third-party adapter that depends on
VMware networking and iSCSI
configuration and management
interfaces.
Required
After you set up the iSCSI adapters, you can create a datastore on iSCSI storage. For details on how to create
and manage datastores, see “Creating Datastores,” on page 160.
This chapter includes the following topics:
n
“ESXi iSCSI SAN Requirements,” on page 70
n
“ESXi iSCSI SAN Restrictions,” on page 70
n
“Setting LUN Allocations for iSCSI,” on page 70
n
“Network Configuration and Authentication,” on page 71
n
“Set Up Independent Hardware iSCSI Adapters,” on page 71
n
“About Dependent Hardware iSCSI Adapters,” on page 74
n
“About the Software iSCSI Adapter,” on page 77
n
“Modify General Properties for iSCSI Adapters,” on page 81
n
“Setting Up iSCSI Network,” on page 81
n
“Using Jumbo Frames with iSCSI,” on page 91
n
“Configuring Discovery Addresses for iSCSI Adapters,” on page 93
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n
“Configuring CHAP Parameters for iSCSI Adapters,” on page 94
n
“Configuring Advanced Parameters for iSCSI,” on page 98
n
“iSCSI Session Management,” on page 99
ESXi iSCSI SAN Requirements
You must meet several requirements for your ESXi host to work properly with a SAN.
n
Verify that your SAN storage hardware and firmware combinations are supported in conjunction with
ESXi systems. For an up-to-date list, see VMware Compatibility Guide.
n
Configure your system to have only one VMFS datastore for each LUN.
n
Unless you are using diskless servers, set up a diagnostic partition on a local storage. If you have
diskless servers that boot from iSCSI SAN, see “General Boot from iSCSI SAN Recommendations,” on
page 103 for information about diagnostic partitions with iSCSI.
n
Use RDMs for access to any raw disk. For information, see Chapter 18, “Raw Device Mapping,” on
page 203.
n
Set the SCSI controller driver in the guest operating system to a large enough queue. For information on
changing queue depth for iSCSI adapters and virtual machines, see vSphere Troubleshooting.
n
On virtual machines running Microsoft Windows, increase the value of the SCSI TimeoutValue
parameter to allow Windows to better tolerate delayed I/O resulting from path failover. For
information, see “Set Timeout on Windows Guest OS,” on page 185.
ESXi iSCSI SAN Restrictions
A number of restrictions exist when you use ESXi with an iSCSI SAN.
n
ESXi does not support iSCSI-connected tape devices.
n
You cannot use virtual-machine multipathing software to perform I/O load balancing to a single
physical LUN.
n
ESXi does not support multipathing when you combine independent hardware adapters with either
software or dependent hardware adapters.
Setting LUN Allocations for iSCSI
When preparing your ESXi system to use iSCSI SAN storage you need to set LUN allocations.
Note the following points:
n
Storage Provisioning. To ensure that the host recognizes LUNs at startup time, configure all iSCSI
storage targets so that your host can access them and use them. Also, configure your host so that it can
discover all available iSCSI targets.
n
vMotion and VMware DRS. When you use vCenter Server and vMotion or DRS, make sure that the
LUNs for the virtual machines are provisioned to all hosts. This configuration provides the greatest
freedom in moving virtual machines.
n
Active-active versus active-passive arrays. When you use vMotion or DRS with an active-passive SAN
storage device, make sure that all hosts have consistent paths to all storage processors. Not doing so can
cause path thrashing when a vMotion migration occurs.
For active-passive storage arrays not listed in Storage/SAN Compatibility, VMware does not support
storage-port failover. You must connect the server to the active port on the storage system. This
configuration ensures that the LUNs are presented to the host.
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Network Configuration and Authentication
Before your ESXi host can discover iSCSI storage, the iSCSI initiators must be configured and authentication
might have to be set up.
n
For software iSCSI and dependent hardware iSCSI, networking for the VMkernel must be configured.
You can verify the network configuration by using the vmkping utility. With software iSCSI and
dependent iSCSI, IPv4 and IPv6 protocols are supported.
n
For independent hardware iSCSI, network parameters, such as IP address, subnet mask, and default
gateway must be configured on the HBA. You can also specify a network protocol, IPv4 or IPv6 for the
adapter.
n
Check and change the default initiator name if necessary.
n
The dynamic discovery address or static discovery address and target name of the storage system must
be set. For software iSCSI and dependent hardware iSCSI, the address should be pingable using
vmkping.
n
For CHAP authentication, enable it on the initiator and the storage system side. After authentication is
enabled, it applies for all of the targets that are not yet discovered, but does not apply to targets that are
already discovered. After the discovery address is set, the new targets discovered are exposed and can
be used at that point.
For details on how to use the vmkping command, search the VMware Knowledge Base.
Set Up Independent Hardware iSCSI Adapters
An independent hardware iSCSI adapter is a specialized third-party adapter capable of accessing iSCSI
storage over TCP/IP. This iSCSI adapter handles all iSCSI and network processing and management for your
ESXi system.
Prerequisites
n
Check whether the adapter needs to be licensed.
n
Install the adapter.
For information about licencing, installation, and firmware updates, see vendor documentation.
Procedure
1
View Independent Hardware iSCSI Adapters on page 72
View an independent hardware iSCSI adapter to verify that it is correctly installed and ready for
configuration.
2
Modify General Properties for iSCSI Adapters on page 72
You can change the default iSCSI name and alias assigned to your iSCSI adapters. For the independent
hardware iSCSI adapters, you can also change the default IP settings.
3
Edit Network Settings for Hardware iSCSI on page 73
After you install an independent hardware iSCSI adapter, you might need to change its default
network settings so that the adapter is configured properly for the iSCSI SAN.
4
Set Up Dynamic or Static Discovery for iSCSI on page 73
With dynamic discovery, each time the initiator contacts a specified iSCSI storage system, it sends the
SendTargets request to the system. The iSCSI system responds by supplying a list of available targets
to the initiator. In addition to the dynamic discovery method, you can use static discovery and
manually enter information for the targets.
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What to do next
If required, configure CHAP parameters and jumbo frames.
View Independent Hardware iSCSI Adapters
View an independent hardware iSCSI adapter to verify that it is correctly installed and ready for
configuration.
After you install an independent hardware iSCSI adapter on a host, it appears on the list of storage adapters
available for configuration. You can view its properties.
Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters.
If installed, the hardware iSCSI adapter appears on the list of storage adapters.
4
Select the adapter to view.
The default details for the adapter appear, including the model, iSCSI name, iSCSI alias, IP address, and
target and paths information.
Modify General Properties for iSCSI Adapters
You can change the default iSCSI name and alias assigned to your iSCSI adapters. For the independent
hardware iSCSI adapters, you can also change the default IP settings.
Important When you modify any default properties for your iSCSI adapters, make sure to use correct
formats for their names and IP addresses.
Prerequisites
Required privilege: Host .Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Properties tab, and click Edit in the General panel.
5
(Optional) Modify the following general properties.
Option
Description
iSCSI Name
Unique name formed according to iSCSI standards that identifies the iSCSI
adapter. If you change the name, make sure that the name you enter is
worldwide unique and properly formatted. Otherwise, certain storage
devices might not recognize the iSCSI adapter.
iSCSI Alias
A friendly name you use instead of the iSCSI name.
If you change the iSCSI name, it is used for new iSCSI sessions. For existing sessions, the new settings are
not used until you log out and log in again.
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Chapter 10 Configuring iSCSI Adapters and Storage
Edit Network Settings for Hardware iSCSI
After you install an independent hardware iSCSI adapter, you might need to change its default network
settings so that the adapter is configured properly for the iSCSI SAN.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Network Settings tab and click Edit.
5
In the IPv4 settings section, disable IPv6 or select the method to obtain IP addresses.
Note The automatic DHCP option and static option are mutually exclusive.
6
Option
Description
No IPv4 settings
Disable IPv4.
Obtain IPv4 settings automatically
Use DHCP to obtain IP settings.
Use static IPv4 settings
Enter the IPv4 IP address, subnet mask, and default gateway for the iSCSI
adapter.
In the IPv6 settings section, disable IPv6 or select an appropriate option for obtaining IPv6 addresses.
Note Automatic options and the static option are mutually exclusive.
7
Option
Description
No IPv6 settings
Disable IPv6.
Enable IPv6
Select an option for obtaining IPv6 addresses.
Obtain IPv6 addresses
automatically through DHCP
Use DHCP to obtain IPv6 addresses.
Obtain IPv6 addresses
automatically through Router
Advertisement
Use router advertisement to obtain IPv6 addresses.
Override Link-local address for IPv6
Override the link-local IP address by configuring a static IP address.
Static IPv6 addresses
a
b
Click Add to add a new IPv6 address.
Enter the IPv6 address and subnet prefix length, and click OK.
In the DNS settings section, provide IP addresses for a preferred DNS server and an alternate DNS
server.
You must provide both values.
Set Up Dynamic or Static Discovery for iSCSI
With dynamic discovery, each time the initiator contacts a specified iSCSI storage system, it sends the
SendTargets request to the system. The iSCSI system responds by supplying a list of available targets to the
initiator. In addition to the dynamic discovery method, you can use static discovery and manually enter
information for the targets.
When you set up static or dynamic discovery, you can only add new iSCSI targets. You cannot change any
parameters of an existing target. To make changes, remove the existing target and add a new one.
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Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Targets tab.
5
Configure the discovery method.
Option
Description
Dynamic Discovery
a Click Dynamic Discovery and click Add.
b Type the IP address or DNS name of the storage system and click OK.
c Rescan the iSCSI adapter.
After establishing the SendTargets session with the iSCSI system, you host
populates the Static Discovery list with all newly discovered targets.
Static Discovery
a
b
c
Click Static Discovery and click Add.
Enter the target’s information and click OK
Rescan the iSCSI adapter.
About Dependent Hardware iSCSI Adapters
A dependent hardware iSCSI adapter is a third-party adapter that depends on VMware networking, and
iSCSI configuration and management interfaces provided by VMware.
An example of a dependent iSCSI adapter is a Broadcom 5709 NIC. When installed on a host, it presents its
two components, a standard network adapter and an iSCSI engine, to the same port. The iSCSI engine
appears on the list of storage adapters as an iSCSI adapter (vmhba). Although the iSCSI adapter is enabled
by default, to make it functional, you must first connect it, through a virtual VMkernel adapter (vmk), to a
physical network adapter (vmnic) associated with it. You can then configure the iSCSI adapter.
After you configure the dependent hardware iSCSI adapter, the discovery and authentication data are
passed through the network connection, while the iSCSI traffic goes through the iSCSI engine, bypassing the
network.
Dependent Hardware iSCSI Considerations
When you use dependent hardware iSCSI adapters with ESXi, certain considerations apply.
74
n
When you use any dependent hardware iSCSI adapter, performance reporting for a NIC associated
with the adapter might show little or no activity, even when iSCSI traffic is heavy. This behavior occurs
because the iSCSI traffic bypasses the regular networking stack.
n
If you use a third-party virtual switch, for example Cisco Nexus 1000V DVS, disable automatic pinning.
Use manual pinning instead, making sure to connect a VMkernel adapter (vmk) to an appropriate
physical NIC (vmnic). For information, refer to your virtual switch vendor documentation.
n
The Broadcom iSCSI adapter performs data reassembly in hardware, which has a limited buffer space.
When you use the Broadcom iSCSI adapter in a congested network or under heavy load, enable flow
control to avoid performance degradation.
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Chapter 10 Configuring iSCSI Adapters and Storage
Flow control manages the rate of data transmission between two nodes to prevent a fast sender from
overrunning a slow receiver. For best results, enable flow control at the end points of the I/O path, at the
hosts and iSCSI storage systems.
To enable flow control for the host, use the esxcli system module parameters command. For details,
see the VMware knowledge base article at http://kb.vmware.com/kb/1013413
n
Dependent hardware adapters support IPv4 and IPv6.
Configure Dependent Hardware iSCSI Adapters
The entire setup and configuration process for the dependent hardware iSCSI adapters involves several
steps. After you set up your adapter, you might need to configure CHAP parameters and Jumbo Frames.
Procedure
1
View Dependent Hardware iSCSI Adapters on page 75
View a dependent hardware iSCSI adapter to verify that it is correctly loaded.
2
Modify General Properties for iSCSI Adapters on page 76
You can change the default iSCSI name and alias assigned to your iSCSI adapters. For the independent
hardware iSCSI adapters, you can also change the default IP settings.
3
Determine Association Between iSCSI and Network Adapters on page 76
You create network connections to bind dependent iSCSI and physical network adapters. To create the
connections correctly, you must determine the name of the physical NIC with which the dependent
hardware iSCSI adapter is associated.
4
Set Up iSCSI Networking on page 77
If you use the software or dependent hardware iSCSI adapters, you must configure connections for the
traffic between the iSCSI component and the physical network adapters.
5
Set Up Dynamic or Static Discovery for iSCSI on page 77
With dynamic discovery, each time the initiator contacts a specified iSCSI storage system, it sends the
SendTargets request to the system. The iSCSI system responds by supplying a list of available targets
to the initiator. In addition to the dynamic discovery method, you can use static discovery and
manually enter information for the targets.
What to do next
If required, configure CHAP parameters and jumbo frames.
View Dependent Hardware iSCSI Adapters
View a dependent hardware iSCSI adapter to verify that it is correctly loaded.
If installed, the dependent hardware iSCSI adapter (vmhba#) appears on the list of storage adapters under
such category as, for example, Broadcom iSCSI Adapter. If the dependent hardware adapter does not appear
on the list of storage adapters, check whether it needs to be licensed. See your vendor documentation.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters.
4
Select the adapter (vmhba#) to view.
The default details for the adapter appear, including the iSCSI name, iSCSI alias, and the status.
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What to do next
Although the dependent iSCSI adapter is enabled by default, to make it functional, you must set up
networking for the iSCSI traffic and bind the adapter to the appropriate VMkernel iSCSI port. You then
configure discovery addresses and CHAP parameters.
Modify General Properties for iSCSI Adapters
You can change the default iSCSI name and alias assigned to your iSCSI adapters. For the independent
hardware iSCSI adapters, you can also change the default IP settings.
Important When you modify any default properties for your iSCSI adapters, make sure to use correct
formats for their names and IP addresses.
Prerequisites
Required privilege: Host .Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Properties tab, and click Edit in the General panel.
5
(Optional) Modify the following general properties.
Option
Description
iSCSI Name
Unique name formed according to iSCSI standards that identifies the iSCSI
adapter. If you change the name, make sure that the name you enter is
worldwide unique and properly formatted. Otherwise, certain storage
devices might not recognize the iSCSI adapter.
iSCSI Alias
A friendly name you use instead of the iSCSI name.
If you change the iSCSI name, it is used for new iSCSI sessions. For existing sessions, the new settings are
not used until you log out and log in again.
Determine Association Between iSCSI and Network Adapters
You create network connections to bind dependent iSCSI and physical network adapters. To create the
connections correctly, you must determine the name of the physical NIC with which the dependent
hardware iSCSI adapter is associated.
Prerequisites
In the vSphere Web Client, browse to the dependent hardware iSCSI adapter (vmhba#). See “View
Dependent Hardware iSCSI Adapters,” on page 75.
Procedure
1
Select the iSCSI adapter (vmhba#) and click the Network Port Binding tab under Adapter Details.
2
Click Add.
The network adapter (vmnic#) that corresponds to the dependent iSCSI adapter is listed in the Physical
Network Adapter column.
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What to do next
If the VMkernel Adapter column is empty, create a VMkernel adapter (vmk#) for the physical network
adapter (vmnic#) and then bind them to the associated dependent hardware iSCSI. See “Setting Up iSCSI
Network,” on page 81.
Set Up iSCSI Networking
If you use the software or dependent hardware iSCSI adapters, you must configure connections for the
traffic between the iSCSI component and the physical network adapters.
Configuring the network connection involves creating a virtual VMkernel adapter for each physical network
adapter. You then associate the VMkernel adapter with an appropriate iSCSI adapter. This process is called
port binding.
For information, see “Setting Up iSCSI Network,” on page 81.
Set Up Dynamic or Static Discovery for iSCSI
With dynamic discovery, each time the initiator contacts a specified iSCSI storage system, it sends the
SendTargets request to the system. The iSCSI system responds by supplying a list of available targets to the
initiator. In addition to the dynamic discovery method, you can use static discovery and manually enter
information for the targets.
When you set up static or dynamic discovery, you can only add new iSCSI targets. You cannot change any
parameters of an existing target. To make changes, remove the existing target and add a new one.
Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Targets tab.
5
Configure the discovery method.
Option
Description
Dynamic Discovery
a Click Dynamic Discovery and click Add.
b Type the IP address or DNS name of the storage system and click OK.
c Rescan the iSCSI adapter.
After establishing the SendTargets session with the iSCSI system, you host
populates the Static Discovery list with all newly discovered targets.
Static Discovery
a
b
c
Click Static Discovery and click Add.
Enter the target’s information and click OK
Rescan the iSCSI adapter.
About the Software iSCSI Adapter
With the software-based iSCSI implementation, you can use standard NICs to connect your host to a remote
iSCSI target on the IP network. The software iSCSI adapter that is built into ESXi facilitates this connection
by communicating with the physical NICs through the network stack.
Before you can use the software iSCSI adapter, you must set up networking, activate the adapter, and
configure parameters such as discovery addresses and CHAP.
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When you use the software iSCSI adapters, keep in mind the following considerations:
n
Designate a separate network adapter for iSCSI. Do not use iSCSI on 100 Mbps or slower adapters.
n
Avoid hard coding the name of the software adapter, vmhbaXX, in the scripts. It is possible for the
name to change from one ESXi release to another. The change might cause failures of your existing
scripts if they use the hardcoded old name. The name change does not affect the behavior of the iSCSI
software adapter.
Configure the Software iSCSI Adapter
The software iSCSI adapter configuration workflow includes these steps.
Procedure
1
Activate the Software iSCSI Adapter on page 78
You must activate your software iSCSI adapter so that your host can use it to access iSCSI storage.
2
Modify General Properties for iSCSI Adapters on page 79
You can change the default iSCSI name and alias assigned to your iSCSI adapters. For the independent
hardware iSCSI adapters, you can also change the default IP settings.
3
Set Up iSCSI Networking on page 79
If you use the software or dependent hardware iSCSI adapters, you must configure connections for the
traffic between the iSCSI component and the physical network adapters.
4
Set Up Dynamic or Static Discovery for iSCSI on page 79
With dynamic discovery, each time the initiator contacts a specified iSCSI storage system, it sends the
SendTargets request to the system. The iSCSI system responds by supplying a list of available targets
to the initiator. In addition to the dynamic discovery method, you can use static discovery and
manually enter information for the targets.
What to do next
If required, configure CHAP parameters and jumbo frames.
Activate the Software iSCSI Adapter
You must activate your software iSCSI adapter so that your host can use it to access iSCSI storage.
You can activate only one software iSCSI adapter.
Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Note If you boot from iSCSI using the software iSCSI adapter, the adapter is enabled and the network
configuration is created at the first boot. If you disable the adapter, it is reenabled each time you boot the
host.
Procedure
78
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and click the Add icon (
4
Select Software iSCSI Adapter and confirm that you want to add the adapter.
).
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Chapter 10 Configuring iSCSI Adapters and Storage
The software iSCSI adapter (vmhba#) is enabled and appears on the list of storage adapters. After enabling
the adapter, the host assigns the default iSCSI name to it. If you need to change the default name, follow
iSCSI naming conventions.
What to do next
Select the adapter and use the Adapter Details section to complete configuration.
Modify General Properties for iSCSI Adapters
You can change the default iSCSI name and alias assigned to your iSCSI adapters. For the independent
hardware iSCSI adapters, you can also change the default IP settings.
Important When you modify any default properties for your iSCSI adapters, make sure to use correct
formats for their names and IP addresses.
Prerequisites
Required privilege: Host .Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Properties tab, and click Edit in the General panel.
5
(Optional) Modify the following general properties.
Option
Description
iSCSI Name
Unique name formed according to iSCSI standards that identifies the iSCSI
adapter. If you change the name, make sure that the name you enter is
worldwide unique and properly formatted. Otherwise, certain storage
devices might not recognize the iSCSI adapter.
iSCSI Alias
A friendly name you use instead of the iSCSI name.
If you change the iSCSI name, it is used for new iSCSI sessions. For existing sessions, the new settings are
not used until you log out and log in again.
Set Up iSCSI Networking
If you use the software or dependent hardware iSCSI adapters, you must configure connections for the
traffic between the iSCSI component and the physical network adapters.
Configuring the network connection involves creating a virtual VMkernel adapter for each physical network
adapter. You then associate the VMkernel adapter with an appropriate iSCSI adapter. This process is called
port binding.
For information, see “Setting Up iSCSI Network,” on page 81.
Set Up Dynamic or Static Discovery for iSCSI
With dynamic discovery, each time the initiator contacts a specified iSCSI storage system, it sends the
SendTargets request to the system. The iSCSI system responds by supplying a list of available targets to the
initiator. In addition to the dynamic discovery method, you can use static discovery and manually enter
information for the targets.
When you set up static or dynamic discovery, you can only add new iSCSI targets. You cannot change any
parameters of an existing target. To make changes, remove the existing target and add a new one.
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Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Targets tab.
5
Configure the discovery method.
Option
Description
Dynamic Discovery
a Click Dynamic Discovery and click Add.
b Type the IP address or DNS name of the storage system and click OK.
c Rescan the iSCSI adapter.
After establishing the SendTargets session with the iSCSI system, you host
populates the Static Discovery list with all newly discovered targets.
Static Discovery
a
b
c
Click Static Discovery and click Add.
Enter the target’s information and click OK
Rescan the iSCSI adapter.
Disable Software iSCSI Adapter
If you do not need the software iSCSI adapter, you can disable it.
Disabling the software iSCSI adapter marks it for removal. The adapter is removed from the host on the next
host reboot. After removal, all virtual machines and other data on the storage devices associated with this
adapter become inaccessible to the host.
Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Properties tab.
5
Click Disable and confirm that you want to disable the adapter.
The status indicates that the adapter is disabled.
6
Reboot the host.
After reboot, the adapter no longer appears on the list of storage adapters.
The iSCSI software adapter is no longer available and storage devices associated with it are inaccessible. You
can later activate the adapter.
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Modify General Properties for iSCSI Adapters
You can change the default iSCSI name and alias assigned to your iSCSI adapters. For the independent
hardware iSCSI adapters, you can also change the default IP settings.
Important When you modify any default properties for your iSCSI adapters, make sure to use correct
formats for their names and IP addresses.
Prerequisites
Required privilege: Host .Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Properties tab, and click Edit in the General panel.
5
(Optional) Modify the following general properties.
Option
Description
iSCSI Name
Unique name formed according to iSCSI standards that identifies the iSCSI
adapter. If you change the name, make sure that the name you enter is
worldwide unique and properly formatted. Otherwise, certain storage
devices might not recognize the iSCSI adapter.
iSCSI Alias
A friendly name you use instead of the iSCSI name.
If you change the iSCSI name, it is used for new iSCSI sessions. For existing sessions, the new settings are
not used until you log out and log in again.
Setting Up iSCSI Network
Software and dependent hardware iSCSI adapters depend on the VMkernel networking. If you use the
software or dependent hardware iSCSI adapters, you must configure connections for the traffic between the
iSCSI component and the physical network adapters.
Configuring the network connection involves creating a virtual VMkernel adapter for each physical network
adapter. You then associate the VMkernel adapter with an appropriate iSCSI adapter. This process is called
port binding.
For specific considerations on when and how to use network connections with software iSCSI, see the
VMware knowledge base article at http://kb.vmware.com/kb/2038869.
Multiple Network Adapters in iSCSI Configuration
If your host has more than one physical network adapter for software and dependent hardware iSCSI, use
the adapters for multipathing.
You can connect the software iSCSI adapter with any physical NICs available on your host. The dependent
iSCSI adapters must be connected only to their own physical NICs.
Note Physical NICs must be on the same subnet as the iSCSI storage system they connect to.
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Figure 10‑1. Networking with iSCSI
Two physical NICs connected to
the software iSCSI adapter
Two physical NICs with iSCSI
offload capabilities
software iSCSI adapter
dependent hardware iSCSI adapters
vmhba#
vmk1
vmhba33
vmhba34
vmk1
vmk2
virtual
adapters
vmk2
vSwitch
vSwitch
Host1
Host1
Host2
vmnic1
vmnic2
vmnic1
physical NICs
vmnic2
virtual
Host2 physical
physical NICs
with iSCSI
offload
capabilities
IP network
iSCSI storage
iSCSI storage
The iSCSI adapter and physical NIC connect through a virtual VMkernel adapter, also called the virtual
network adapter or the VMkernel port. You create a VMkernel adapter (vmk) on a vSphere switch (vSwitch)
using 1:1 mapping between each virtual and physical network adapter.
One way to achieve the 1:1 mapping when you have multiple NICs, is to designate a separate vSphere
switch for each virtual-to-physical adapter pair.
Note If you use separate vSphere switches, you must connect them to different IP subnets. Otherwise,
VMkernel adapters might experience connectivity problems and the host fails to discover the iSCSI LUNs.
The following examples show configurations that use vSphere standard switches, but you can use
distributed switches as well. For more information about vSphere distributed switches, see the vSphere
Networking documentation.
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Figure 10‑2. 1:1 Adapter Mapping on Separate vSphere Standard Switches
vSwitch1
Physical adapters
VMkernel adapters
vmnic1
iSCSI1
vmk1
vSwitch2
Physical adapters
VMkernel adapters
vmnic2
iSCSI2
vmk2
An alternative is to add all NICs and VMkernel adapters to a single vSphere standard switch. In this case,
you must override the default network setup and make sure that each VMkernel adapter maps to only one
corresponding active physical adapter.
Note If the VMkernel adapters are on the same subnet, use the single vSwitch configuration.
Figure 10‑3. 1:1 Adapter Mapping on a Single vSphere Standard Switch
vSwitch1
VMkernel adapters
Physical adapters
iSCSI2
vmnic2
vmk2
vmnic1
iSCSI1
vmk1
The following table summarizes the iSCSI networking configuration discussed in this topic.
Table 10‑2. Networking Configuration for iSCSI
iSCSI Adapters
VMkernel Adapters (Ports)
Physical Adapters (NICs)
vmk1
vmnic1
vmk2
vmnic2
vmhbaX3
vmk1
vmnic1
vmhbaX4
vmk2
vmnic2
Software iSCSI
vmhbaX2
Dependent Hardware iSCSI
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Requirements for iSCSI Port Binding
You can use multiple VMkernel adapters bound to iSCSI to have multiple paths to an iSCSI array that
broadcasts a single IP address.
When you use port binding for multipathing, follow these guidelines:
iSCSI ports of the array target must reside in the same broadcast domain and IP subnet as the VMkernel
adapters.
n
n
All VMkernel adapters used for iSCSI port binding must reside in the same broadcast domain and IP
subnet.
n
All VMkernel adapters used for iSCSI connectivity must reside in the same virtual switch.
Do not use port binding when any of the following conditions exist:
Array target iSCSI ports are in a different broadcast domain and IP subnet.
n
n
VMkernel adapters used for iSCSI connectivity exist in different broadcast domains, IP subnets, or use
different virtual switches.
Best Practices for Configuring Networking with Software iSCSI
When you configure networking with software iSCSI, consider several best practices.
Software iSCSI Port Binding
You can bind the software iSCSI initiator on the ESXi host to a single or multiple VMkernel ports, so that
iSCSI traffic flows only through the bound ports. When port binding is configured, the iSCSI initiator creates
iSCSI sessions from all bound ports to all configured target portals.
See the following examples.
VMkernel Ports
Target Portals
iSCSI Sessions
2 bound VMkernel ports
2 target portals
4 sessions (2 x 2)
4 bound VMkernel ports
1 target portal
4 sessions (4 x 1)
2 bound VMkernel ports
4 target portals
8 sessions (2 x 4)
Note Make sure that all target portals are reachable from all VMkernel ports when port binding is used.
Otherwise, iSCSI sessions might fail to create. As a result, the rescan operation might take longer than
expected.
No Port Binding
If you do not use port binding, the ESXi networking layer selects the best VMkernel port based on its
routing table. The host uses the port to create an iSCSI session with the target portal. Without the port
binding, only one session per each target portal is created.
See the following examples.
VMkernel Ports
Target Portals
iSCSI Sessions
2 unbound VMkernel ports
2 target portals
2 sessions
4 unbound VMkernel ports
1 target portal
1 session
2 unbound VMkernel ports
4 target portals
4 sessions
Software iSCSI Multipathing
Example 1. Multiple paths for an iSCSI target with a single network portal
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If your target has only one network portal, you can create multiple paths to the target by adding multiple
VMkernel ports on your ESXi host and binding them to the iSCSI initiator.
vmk1
192.168.0.1/24
vmnic1
Same subnet
vmk2
192.168.0.2/24
vmnic2
IP
Network
vmk3
Single Target:
192.168.0.10/24
192.168.0.3/24
vmnic3
vmk2
192.168.0.4/24
vmnic4
In this example, all initiator ports and the target portal are configured in the same subnet. The target is
reachable through all bound ports. You have four VMkernel ports and one target portal, so total of four
paths are created.
Without the port binding, only one path is created.
Example 2. Multiple paths with VMkernel ports in different subnets
You can create multiple paths by configuring multiple ports and target portals on different IP subnets. By
keeping initiator and target ports in different subnets, you can force ESXi to create paths through specific
ports. In this configuration, you do not use port binding because port binding requires that all initiator and
target ports are on the same subnet.
vmk1
SP/Controller A:
192.168.1.1/24
Port 0: 192.168.1.10/24
vmnic1
Port 1: 192.168.2.10/24
IP
Network
vmk2
SP/Controller B:
192.168.2.1/24
Port 0: 192.168.1.11/24
vmnic2
Port 1: 192.168.2.11/24
ESXi selects vmk1 when connecting to Port 0 of Controller A and Controller B because all three ports are on
the same subnet. Similarly, vmk2 is selected when connecting to Port 1of Controller A and B. You can use
NIC teaming in this configuration.
Total of four paths are created.
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Paths
Description
Path 1
vmk1 and Port0 of Controller A
Path 2
vmk1 and Port0 of Controlled B
Path 3
vmk2 and Port1 of Controller A
Path 4
vmk2 and Port2 of Controller B
Routing with Software iSCSI
You can use the esxcli command to add static routes for your iSCSI traffic. After you configure static routes,
initiator and target ports in different subnets can communicate with each other.
Example 1. Using static routes with port binding
In this example, you keep all bound vmkernel ports in one subnet (N1) and configure all target portals in
another subnet (N2). You can then add a static route for the target subnet (N2).
N1
N2
vmk1
SP/Controller A
Port 0
10.115.179.1/24
192.168.1.1/24
vmnic1
IP
Network
vmk2
SP/Controller B
Port 0
10.115.179.2/24
192.168.1.2/24
vmnic2
Use the following command:
# esxcli network ip route ipv4 add -gateway 192.168.1.253 -network 10.115.179.0/24
Example 2. Using static routes to create multiple paths
In this configuration, you use static routing when using different subnets. You cannot use the port binding
with this configuration.
vmk1
SP/Controller A
Port 0
0.115.155.1/24
192.168.1.1/24
vmnic1
IP
Network
vmk2
192.168.2.1/24
vmnic2
SP/Controller A
Port 0
0.115.179.1/24
You configure vmk1 and vmk2 in separate subnets, 192.168.1.0 and 192.168.2.0. Your target portals are also
in separate subnets, 10.115.155.0 and 10.155.179.0.
You can add the static route for 10.115.155.0 from vmk1. Make sure that the gateway is reachable from
vmk1.
# esxcli network ip route ipv4 add -gateway 192.168.1.253 -network 10.115.155.0/24
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You then add static route for 10.115.179.0 from vmk2. Make sure that the gateway is reachable from vmk2.
# esxcli network ip route ipv4 add -gateway 192.168.2.253 -network 10.115.179.0/24
When connecting with Port 0 of Controller A, vmk1 is used.
When connecting with Port 0 of Controller B, vmk2 is used.
Example 3. Routing with a separate gateway per vmkernel port
Starting with vSphere 6.5, you can configure a separate gateway per VMkernel port. If you use DHCP to
obtain IP configuration for a VMkernel port, gateway information can also be obtained using DHCP.
To see gateway information per VMkernel port, use the following command:
# esxcli network ip interface ipv4 address list
Name
---vmk0
vmk1
vmk2
IPv4 Address
-------------10.115.155.122
10.115.179.209
10.115.179.146
IPv4 Netmask
------------255.255.252.0
255.255.252.0
255.255.252.0
IPv4 Broadcast
-------------10.115.155.255
10.115.179.255
10.115.179.255
Address Type
-----------DHCP
DHCP
DHCP
Gateway
-------------10.115.155.253
10.115.179.253
10.115.179.253
DHCP DNS
-------true
true
true
With separate gateways per VMkernel port, you use port binding to reach targets in different subnets.
Configure Port Binding for iSCSI
iSCSI port binding creates connections for the traffic between the software or dependent hardware iSCSI
adapters and the physical network adapters.
The following tasks discuss the iSCSI network configuration with a vSphere standard switch.
®
®
You can also use the VMware vSphere Distributed Switch™ and VMware NSX Virtual Switch™ in the
iSCSI port biding configuration. For information about NSX virtual switches, see the VMware NSX
documentation.
If you use a vSphere distributed switch with multiple uplink ports, for port binding, create a separate
distributed port group per each physical NIC. Then set the team policy so that each distributed port group
has only one active uplink port. For detailed information on distributed switches, see the vSphere Networking
documentation.
Procedure
1
Create a Single VMkernel Adapter for iSCSI on page 88
Connect the VMkernel, which runs services for iSCSI storage, to a physical network adapter.
2
Create Additional VMkernel Adapters for iSCSI on page 88
Use this task if you have two or more physical network adapters for iSCSI. And you want to connect
all your physical adapters to a single vSphere standard switch. In this task, you add the physical
adapters and VMkernel adapters to an existing vSphere standard switch.
3
Change Network Policy for iSCSI on page 89
If you use a single vSphere standard switch to connect multiple VMkernel adapters to multiple
network adapters, set up network policy so that only one physical network adapter is active for each
VMkernel adapter.
4
Bind iSCSI and VMkernel Adapters on page 90
Bind an iSCSI adapter with a VMkernel adapter.
5
Review Port Binding Details on page 90
Review networking details of the VMkernel adapter that is bound to the iSCSI adapter.
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Create a Single VMkernel Adapter for iSCSI
Connect the VMkernel, which runs services for iSCSI storage, to a physical network adapter.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click Actions > Add Networking.
3
Select VMkernel Network Adapter, and click Next.
4
Select New standard switch to create a vSphere standard switch.
5
Click the Add adapters icon, and select the network adapter (vmnic#) to use for iSCSI.
Make sure to assign the adapter to Active Adapters.
Important If you are creating a VMkernel adapter for dependent hardware iSCSI, select the network
adapter that corresponds to the iSCSI component. See “Determine Association Between iSCSI and
Network Adapters,” on page 76.
6
Enter a network label.
A network label is a friendly name that identifies the VMkernel adapter that you are creating, for
example, iSCSI.
7
Specify the IP settings.
8
Review the information and click Finish.
You created the virtual VMkernel adapter (vmk#) for a physical network adapter (vmnic#) on your host.
What to do next
If your host has one physical network adapter for iSCSI traffic, you must bind the virtual adapter that you
created to the iSCSI adapter.
If you have multiple network adapters, create additional VMkernel adapters and then perform iSCSI
binding. The number of virtual adapters must correspond to the number of physical adapters on the host.
Create Additional VMkernel Adapters for iSCSI
Use this task if you have two or more physical network adapters for iSCSI. And you want to connect all your
physical adapters to a single vSphere standard switch. In this task, you add the physical adapters and
VMkernel adapters to an existing vSphere standard switch.
Prerequisites
Create a vSphere standard switch that maps an iSCSI VMkernel adapter to a single physical network
adapter designated for iSCSI traffic.
Procedure
88
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Networking, click Virtual switches, and select the vSphere switch that you want to modify from
the list.
4
Connect additional network adapters to the switch.
a
Click the Add host networking icon.
b
Select Physical Network Adapters, and click Next.
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c
Make sure that you are using the existing switch, and click Next.
d
Click the Add adapters icon, and select one or more network adapters (vmnic#) to use for iSCSI.
With dependent hardware iSCSI adapters, select only those NICs that have a corresponding iSCSI
component.
e
5
Complete configuration, and click Finish.
Create iSCSI VMkernel adapters for all physical network adapters that you added.
The number of VMkernel interfaces must correspond to the number of physical network adapters on
the vSphere standard switch.
a
Click the Add host networking icon.
b
Select VMkernel Network Adapter, and click Next.
c
Make sure that you are using the existing switch, and click Next.
d
Complete configuration, and click Finish.
What to do next
Change the network policy for all VMkernel adapters, so that only one physical network adapter is active
for each VMkernel adapter. You can then bind the iSCSI VMkernel adapters to the software iSCSI or
dependent hardware iSCSI adapters.
Change Network Policy for iSCSI
If you use a single vSphere standard switch to connect multiple VMkernel adapters to multiple network
adapters, set up network policy so that only one physical network adapter is active for each VMkernel
adapter.
By default, for each VMkernel adapter on the vSphere standard switch, all network adapters appear as
active. You must override this setup, so that each VMkernel adapter maps to only one corresponding active
physical. For example, vmk1 maps to vmnic1, vmk2 maps to vmnic2, and so on.
Prerequisites
Create a vSphere standard switch that connects VMkernel with physical network adapters designated for
iSCSI traffic. The number of VMkernel adapters must correspond to the number of physical adapters on the
vSphere standard switch.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Networking, click Virtual switches, and select the vSphere switch that you want to modify from
the list.
4
On the vSwitch diagram, select the VMkernel adapter and click the Edit Settings icon.
5
On the Edit Settings wizard, click Teaming and Failover and select Override under Failover Order.
6
Designate only one physical adapter as active and move all remaining adapters to the Unused Adapters
category.
7
Repeat Step 4 through Step 6 for each iSCSI VMkernel interface on the vSphere standard switch.
Example: iSCSI Network Policy
The following table illustrates the proper iSCSI mapping where only one physical network adapter is active
for each VMkernel adapter.
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VMkernel Adapter (vmk#)
Physical Network Adapter (vmnic#)
vmk1
Active Adapters
vmnic1
Unused Adapters
vmnic2
vmk2
Active Adapters
vmnic2
Unused Adapters
vmnic1
What to do next
After you perform this task, bind the virtual VMkernel adapters to the software iSCSI or dependent
hardware iSCSI adapters.
Bind iSCSI and VMkernel Adapters
Bind an iSCSI adapter with a VMkernel adapter.
Prerequisites
Create a virtual VMkernel adapter for each physical network adapter on your host. If you use multiple
VMkernel adapters, set up the correct network policy.
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the software or dependent iSCSI adapter to configure
from the list.
4
Under Adapter Details, click the Network Port Binding tab and click the Add icon ( ).
5
Select a VMkernel adapter to bind with the iSCSI adapter.
Note Make sure that the network policy for the VMkernel adapter is compliant with the binding
requirements.
You can bind the software iSCSI adapter to one or more VMkernel adapters. For a dependent hardware
iSCSI adapter, only one VMkernel adapter associated with the correct physical NIC is available.
6
Click OK.
The network connection appears on the list of VMkernel port bindings for the iSCSI adapter.
Review Port Binding Details
Review networking details of the VMkernel adapter that is bound to the iSCSI adapter.
Procedure
90
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the software or dependent iSCSI adapter from the
list.
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4
Under Adapter Details, click the Network Port Binding tab and click the View Details icon.
5
Review the VMkernel adapter information by switching between available tabs.
Managing iSCSI Network
Special consideration apply to network adapters, both physical and VMkernel, that are associated with an
iSCSI adapter.
After you create network connections for iSCSI, an iSCSI indicator on a number of Networking dialog boxes
becomes enabled. This indicator shows that a particular virtual or physical network adapter is iSCSI-bound.
To avoid disruptions in iSCSI traffic, follow these guidelines and considerations when managing iSCSIbound virtual and physical network adapters:
n
Make sure that the VMkernel network adapters are assigned addresses on the same subnet as the iSCSI
storage portal they connect to.
n
iSCSI adapters using VMkernel adapters are not able to connect to iSCSI ports on different subnets,
even if those ports are discovered by the iSCSI adapters.
n
When using separate vSphere switches to connect physical network adapters and VMkernel adapters,
make sure that the vSphere switches connect to different IP subnets.
n
If VMkernel adapters are on the same subnet, they must connect to a single vSwitch.
n
If you migrate VMkernel adapters to a different vSphere switch, move associated physical adapters.
n
Do not make configuration changes to iSCSI-bound VMkernel adapters or physical network adapters.
n
Do not make changes that might break association of VMkernel adapters and physical network
adapters. You can break the association if you remove one of the adapters or the vSphere switch that
connects them, or change the 1:1 network policy for their connection.
iSCSI Network Troubleshooting
A warning sign indicates non-compliant port group policy for an iSCSI-bound VMkernel adapter.
Problem
The VMkernel adapter's port group policy is considered non-compliant in the following cases:
n
The VMkernel adapter is not connected to an active physical network adapter.
n
The VMkernel adapter is connected to more than one physical network adapter.
n
The VMkernel adapter is connected to one or more standby physical adapters.
n
The active physical adapter is changed.
Solution
Follow the steps in “Change Network Policy for iSCSI,” on page 89 to set up the correct network policy for
the iSCSI-bound VMkernel adapter.
Using Jumbo Frames with iSCSI
ESXi supports the use of Jumbo Frames with iSCSI.
Jumbo Frames are Ethernet frames with the size that exceeds 1500 Bytes. The maximum transmission unit
(MTU) parameter is typically used to measure the size of Jumbo Frames. ESXi allows Jumbo Frames with
the MTU up to 9000 Bytes.
When you use Jumbo Frames for iSCSI traffic, the following considerations apply:
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n
Check with your vendors to ensure your physical NICs and iSCSI HBAs support Jumbo Frames.
n
To set up and verify physical network switches for Jumbo Frames, consult your vendor documentation.
The following table explains the level of support that ESXi provides to Jumbo Frames.
Table 10‑3. Support of Jumbo Frames
Type of iSCSI Adapters
Jumbo Frames Support
Software iSCSI
Supported
Dependent Hardware iSCSI
Supported. Check with vendor.
Independent Hardware iSCSI
Supported. Check with vendor.
Enable Jumbo Frames for Software and Dependent Hardware iSCSI
To enable Jumbo Frames for software and dependent hardware iSCSI adapters in the vSphere Web Client,
change the default value of the maximum transmission units (MTU) parameter.
You change the MTU parameter on the vSphere switch that you use for iSCSI traffic. For more information,
see the vSphere Networking documentation.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Networking, click Virtual switches, and select the vSphere switch that you want to modify from
the list.
4
Click the Edit settings icon.
5
On the Properties page, change the MTU parameter.
This step sets the MTU for all physical NICs on that standard switch. The MTU value should be set to
the largest MTU size among all NICs connected to the standard switch. ESXi supports the MTU size up
to 9000 Bytes.
Enable Jumbo Frames for Independent Hardware iSCSI
To enable Jumbo Frames for independent hardware iSCSI adapters in the vSphere Web Client, change the
default value of the maximum transmission units (MTU) parameter.
Use the Advanced Options settings to change the MTU parameter for the iSCSI HBA.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the independent hardware iSCSI adapter from the
list of adapters.
4
Under Adapter Details, click the Advanced Options tab and click Edit.
5
Change the value of the MTU parameter.
ESXi supports the MTU size up to 9000 Bytes.
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Configuring Discovery Addresses for iSCSI Adapters
You need to set up target discovery addresses, so that the iSCSI adapter can determine which storage
resource on the network is available for access.
The ESXi system supports these discovery methods:
Dynamic Discovery
Also known as SendTargets discovery. Each time the initiator contacts a
specified iSCSI server, the initiator sends the SendTargets request to the
server. The server responds by supplying a list of available targets to the
initiator. The names and IP addresses of these targets appear on the Static
Discovery tab. If you remove a static target added by dynamic discovery, the
target might be returned to the list the next time a rescan happens, the iSCSI
adapter is reset, or the host is rebooted.
Note With software and dependent hardware iSCSI, ESXi filters target
addresses based on the IP family of the iSCSI server address specified. If the
address is IPv4, IPv6 addresses that might come in the SendTargets response
from the iSCSI server are filtered out. When DNS names are used to specify
an iSCSI server, or when the SendTargets response from the iSCSI server has
DNS names, ESXi relies on the IP family of the first resolved entry from DNS
lookup.
Static Discovery
In addition to the dynamic discovery method, you can use static discovery
and manually enter information for the targets. The iSCSI adapter uses a list
of targets that you provide to contact and communicate with the iSCSI
servers.
Set Up Dynamic or Static Discovery for iSCSI
With dynamic discovery, each time the initiator contacts a specified iSCSI storage system, it sends the
SendTargets request to the system. The iSCSI system responds by supplying a list of available targets to the
initiator. In addition to the dynamic discovery method, you can use static discovery and manually enter
information for the targets.
When you set up static or dynamic discovery, you can only add new iSCSI targets. You cannot change any
parameters of an existing target. To make changes, remove the existing target and add a new one.
Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Under Adapter Details, click the Targets tab.
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5
Configure the discovery method.
Option
Description
Dynamic Discovery
a Click Dynamic Discovery and click Add.
b Type the IP address or DNS name of the storage system and click OK.
c Rescan the iSCSI adapter.
After establishing the SendTargets session with the iSCSI system, you host
populates the Static Discovery list with all newly discovered targets.
Static Discovery
a
b
c
Click Static Discovery and click Add.
Enter the target’s information and click OK
Rescan the iSCSI adapter.
Remove Dynamic or Static iSCSI Targets
Remove iSCSI servers that appear on the list of targets.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the iSCSI adapter to modify from the list.
4
Under Adapter Details, click the Targets tab.
5
Switch between Dynamic Discovery and Static Discovery.
6
Select an iSCSI server to remove and click Remove.
7
Rescan the iSCSI adapter.
If you are removing the static target that was dynamically discovered, you need to remove it from the
storage system before performing the rescan. Otherwise, your host will automatically discover and add
the target to the list of static targets when you rescan the adapter.
Configuring CHAP Parameters for iSCSI Adapters
Because the IP networks that the iSCSI technology uses to connect to remote targets do not protect the data
they transport, you must ensure security of the connection. One of the protocols that iSCSI implements is the
Challenge Handshake Authentication Protocol (CHAP), which verifies the legitimacy of initiators that access
targets on the network.
CHAP uses a three-way handshake algorithm to verify the identity of your host and, if applicable, of the
iSCSI target when the host and target establish a connection. The verification is based on a predefined
private value, or CHAP secret, that the initiator and target share.
ESXi supports CHAP authentication at the adapter level. In this case, all targets receive the same CHAP
name and secret from the iSCSI initiator. For software and dependent hardware iSCSI adapters, ESXi also
supports per-target CHAP authentication, which allows you to configure different credentials for each target
to achieve greater level of security.
Choosing CHAP Authentication Method
ESXi supports unidirectional CHAP for all types of iSCSI initiators, and bidirectional CHAP for software
and dependent hardware iSCSI.
Before configuring CHAP, check whether CHAP is enabled at the iSCSI storage system and check the CHAP
authentication method the system supports. If CHAP is enabled, enable it for your initiators, making sure
that the CHAP authentication credentials match the credentials on the iSCSI storage.
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ESXi supports the following CHAP authentication methods:
Unidirectional CHAP
In unidirectional CHAP authentication, the target authenticates the initiator,
but the initiator does not authenticate the target.
Bidirectional CHAP
In bidirectional CHAP authentication, an additional level of security enables
the initiator to authenticate the target. VMware supports this method for
software and dependent hardware iSCSI adapters only.
For software and dependent hardware iSCSI adapters, you can set unidirectional CHAP and bidirectional
CHAP for each adapter or at the target level. Independent hardware iSCSI supports CHAP only at the
adapter level.
When you set the CHAP parameters, specify a security level for CHAP.
Note When you specify the CHAP security level, how the storage array responds depends on the array’s
CHAP implementation and is vendor specific. For information on CHAP authentication behavior in
different initiator and target configurations, consult the array documentation.
Table 10‑4. CHAP Security Level
CHAP Security Level
Description
Supported
None
The host does not use CHAP authentication. Select this
option to disable authentication if it is currently
enabled.
Software iSCSI
Dependent hardware iSCSI
Independent hardware
iSCSI
Use unidirectional CHAP if
required by target
The host prefers a non-CHAP connection, but can use a
CHAP connection if required by the target.
Software iSCSI
Dependent hardware iSCSI
Use unidirectional CHAP
unless prohibited by target
The host prefers CHAP, but can use non-CHAP
connections if the target does not support CHAP.
Software iSCSI
Dependent hardware iSCSI
Independent hardware
iSCSI
Use unidirectional CHAP
The host requires successful CHAP authentication. The
connection fails if CHAP negotiation fails.
Software iSCSI
Dependent hardware iSCSI
Independent hardware
iSCSI
Use bidirectional CHAP
The host and the target support bidirectional CHAP.
Software iSCSI
Dependent hardware iSCSI
Set Up CHAP for iSCSI Adapter
When you set up CHAP name and secret at the iSCSI adapter level, all targets receive the same parameters
from the adapter. By default, all discovery addresses or static targets inherit CHAP parameters that you set
up at the adapter level.
The CHAP name should not exceed 511 alphanumeric characters and the CHAP secret should not exceed
255 alphanumeric characters. Some adapters, for example the QLogic adapter, might have lower limits, 255
for the CHAP name and 100 for the CHAP secret.
Prerequisites
n
Before setting up CHAP parameters for software or dependent hardware iSCSI, determine whether to
configure unidirectional or bidirectional CHAP. Independent hardware iSCSI adapters do not support
bidirectional CHAP.
n
Verify CHAP parameters configured on the storage side. Parameters that you configure must match the
ones one the storage side.
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n
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Display storage adapters and select the iSCSI adapter to configure.
2
Under Adapter Details, click the Properties tab and click Edit in the Authentication panel.
3
Specify authentication method.
4
n
None
n
Use unidirectional CHAP if required by target
n
Use unidirectional CHAP unless prohibited by target
n
Use unidirectional CHAP
n
Use bidirectional CHAP. To configure bidirectional CHAP, you must select this option.
Specify the outgoing CHAP name.
Make sure that the name you specify matches the name configured on the storage side.
n
To set the CHAP name to the iSCSI adapter name, select Use initiator name.
n
To set the CHAP name to anything other than the iSCSI initiator name, deselect Use initiator name
and type a name in the Name text box.
5
Enter an outgoing CHAP secret to be used as part of authentication. Use the same secret that you enter
on the storage side.
6
If configuring bidirectional CHAP, specify incoming CHAP credentials.
Make sure to use different secrets for the outgoing and incoming CHAP.
7
Click OK.
8
Rescan the iSCSI adapter.
If you change the CHAP parameters, they are used for new iSCSI sessions. For existing sessions, new
settings are not used until you log out and log in again.
Set Up CHAP for Target
If you use software and dependent hardware iSCSI adapters, you can configure different CHAP credentials
for each discovery address or static target.
The CHAP name should not exceed 511 and the CHAP secret 255 alphanumeric characters.
Prerequisites
n
Before setting up CHAP parameters for software or dependent hardware iSCSI, determine whether to
configure unidirectional or bidirectional CHAP.
n
Verify CHAP parameters configured on the storage side. Parameters that you configure must match the
ones one the storage side.
n
Access storage adapters.
n
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
96
1
Select the iSCSI adapter to configure, and click the Targets tab under Adapter Details.
2
Click either Dynamic Discovery or Static Discovery.
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Chapter 10 Configuring iSCSI Adapters and Storage
3
From the list of available targets, select a target to configure and click Authentication.
4
Deselect Inherit settings from parent and specify authentication method.
5
n
None
n
Use unidirectional CHAP if required by target
n
Use unidirectional CHAP unless prohibited by target
n
Use unidirectional CHAP
n
Use bidirectional CHAP. To configure bidirectional CHAP, you must select this option.
Specify the outgoing CHAP name.
Make sure that the name you specify matches the name configured on the storage side.
n
To set the CHAP name to the iSCSI adapter name, select Use initiator name.
n
To set the CHAP name to anything other than the iSCSI initiator name, deselect Use initiator name
and type a name in the Name text box.
6
Enter an outgoing CHAP secret to be used as part of authentication. Use the same secret that you enter
on the storage side.
7
If configuring bi-directional CHAP, specify incoming CHAP credentials.
Make sure to use different secrets for the outgoing and incoming CHAP.
8
Click OK.
9
Rescan the iSCSI adapter.
If you change the CHAP parameters, they are used for new iSCSI sessions. For existing sessions, new
settings are not used until you log out and login again.
Disable CHAP
You can disable CHAP if your storage system does not require it.
If you disable CHAP on a system that requires CHAP authentication, existing iSCSI sessions remain active
until you reboot your host, end the session through the command line, or the storage system forces a logout.
After the session ends, you can no longer connect to targets that require CHAP.
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Open the CHAP Credentials dialog box.
2
For software and dependent hardware iSCSI adapters, to disable just the mutual CHAP and leave the
one-way CHAP, select Do not use CHAP in the Mutual CHAP area.
3
To disable one-way CHAP, select Do not use CHAP in the CHAP area.
The mutual CHAP, if set up, automatically turns to Do not use CHAP when you disable the one-way
CHAP.
4
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Click OK.
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Configuring Advanced Parameters for iSCSI
You might need to configure additional parameters for your iSCSI initiators. For example, some iSCSI
storage systems require ARP (Address Resolution Protocol) redirection to move iSCSI traffic dynamically
from one port to another. In this case, you must activate ARP redirection on your host.
The following table lists advanced iSCSI parameters that you can configure using the vSphere Web Client. In
addition, you can use the vSphere CLI commands to configure some of the advanced parameters. For
information, see the Getting Started with vSphere Command-Line Interfaces documentation.
Important Do not make any changes to the advanced iSCSI settings unless you are directed by VMware
support or Storage Vendors.
Table 10‑5. Additional Parameters for iSCSI Initiators
98
Advanced Parameter
Description
Configurable On
Header Digest
Increases data integrity. When header digest is enabled, the system
performs a checksum over each iSCSI Protocol Data Unit’s (PDU’s)
header part and verifies using the CRC32C algorithm.
Software iSCSI
Dependent Hardware
iSCSI
Data Digest
Increases data integrity. When data digest is enabled, the system
performs a checksum over each PDU's data part and verifies using
the CRC32C algorithm.
Note Systems that use Intel Nehalem processors offload the iSCSI
digest calculations for software iSCSI, thus reducing the impact on
performance.
Software iSCSI
Dependent Hardware
iSCSI
Maximum
Outstanding R2T
Defines the R2T (Ready to Transfer) PDUs that can be in transition
before an acknowledge PDU is received.
Software iSCSI
Dependent Hardware
iSCSI
First Burst Length
Specifies the maximum amount of unsolicited data an iSCSI
initiator can send to the target during the execution of a single SCSI
command, in bytes.
Software iSCSI
Dependent Hardware
iSCSI
Maximum Burst
Length
Maximum SCSI data payload in a Data-In or a solicited Data-Out
iSCSI sequence, in bytes.
Software iSCSI
Dependent Hardware
iSCSI
Maximum Receive
Data Segment Length
Maximum data segment length, in bytes, that can be received in an
iSCSI PDU.
Software iSCSI
Dependent Hardware
iSCSI
Session Recovery
Timeout
Specifies the amount of time, in seconds, that can lapse while a
session recovery is performed. If the timeout exceeds its limit, the
iSCSI initiator terminates the session.
Software iSCSI
Dependent Hardware
iSCSI
No-Op Interval
Specifies the time interval, in seconds, between NOP-Out requests
sent from your iSCSI initiator to an iSCSI target. The NOP-Out
requests serve as the ping mechanism to verify that a connection
between the iSCSI initiator and the iSCSI target is active.
Software iSCSI
Dependent Hardware
iSCSI
No-Op Timeout
Specifies the amount of time, in seconds, that can lapse before your
host receives a NOP-In message. The message is sent by the iSCSI
target in response to the NOP-Out request. When the no-op timeout
limit is exceeded, the initiator terminates the current session and
starts a new one.
Software iSCSI
Dependent Hardware
iSCSI
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Table 10‑5. Additional Parameters for iSCSI Initiators (Continued)
Advanced Parameter
Description
Configurable On
ARP Redirect
Allows storage systems to move iSCSI traffic dynamically from one
port to another. ARP is required by storage systems that do arraybased failover.
Software iSCSI
Dependent Hardware
iSCSI
Independent Hardware
iSCSI
Delayed ACK
Allows systems to delay acknowledgment of received data packets.
Software iSCSI
Dependent Hardware
iSCSI
Configure Advanced Parameters for iSCSI
The advanced iSCSI settings control such parameters as header and data digest, ARP redirection, delayed
ACK, and so on.
Caution Do not make any changes to the advanced iSCSI settings unless you are working with the
VMware support team or otherwise have thorough information about the values to provide for the settings.
Prerequisites
Required privilege: Host.Configuration.Storage Partition Configuration
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter (vmhba#) to configure.
4
Configure advanced parameters.
5
n
To configure advanced parameters at the adapter level, under Adapter Details, click the Advanced
Options tab and click Edit.
n
Configure advanced parameters at the target level.
a
Click the Targets tab and click either Dynamic Discovery or Static Discovery.
b
From the list of available targets, select a target to configure and click Advanced Options.
Enter any required values for the advanced parameters you want to modify.
iSCSI Session Management
To communicate with each other, iSCSI initiators and targets establish iSCSI sessions. You can review and
manage iSCSI sessions using vSphere CLI.
By default, software iSCSI and dependent hardware iSCSI initiators start one iSCSI session between each
initiator port and each target port. If your iSCSI initiator or target have more than one port, your host can
have multiple sessions established. The default number of sessions for each target equals the number of
ports on the iSCSI adapter times the number of target ports.
Using vSphere CLI, you can display all current sessions to analyze and debug them. To create more paths to
storage systems, you can increase the default number of sessions by duplicating existing sessions between
the iSCSI adapter and target ports.
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You can also establish a session to a specific target port. This can be useful if your host connects to a singleport storage system that, by default, presents only one target port to your initiator, but can redirect
additional sessions to a different target port. Establishing a new session between your iSCSI initiator and
another target port creates an additional path to the storage system.
The following considerations apply to iSCSI session management:
n
Some storage systems do not support multiple sessions from the same initiator name or endpoint.
Attempts to create multiple sessions to such targets can result in unpredictable behavior of your iSCSI
environment.
n
Storage vendors can provide automatic session managers. Using the automatic session manages to add
or delete sessions, does not guarantee lasting results and can interfere with the storage performance.
Review iSCSI Sessions
Use the vCLI command to display iSCSI sessions between an iSCSI adapter and a storage system.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To list iSCSI sessions, run the following command:
esxcli --server=server_name iscsi session list
The command takes these options:
Option
Description
-A|--adapter=str
The iSCSI adapter name, for example, vmhba34.
-s|--isid=str
The iSCSI session identifier.
-n|--name=str
The iSCSI target name, for example, iqn.X.
Add iSCSI Sessions
Use the vCLI to add an iSCSI session for a target you specify or to duplicate an existing session. By
duplicating sessions, you increase the default number of sessions and create additional paths to storage
systems.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
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Procedure
u
To add or duplicate an iSCSI session, run the followign command:
esxcli --server=server_name iscsi session add
The command takes these options:
Option
Description
-A|--adapter=str
The iSCSI adapter name, for example, vmhba34. This option is required.
-s|--isid=str
The ISID of a session to duplicate. You can find it by listing all session.
-n|--name=str
The iSCSI target name, for example, iqn.X.
What to do next
Rescan the iSCSI adapter.
Remove iSCSI Sessions
Use the vCLI command to remove an iSCSI session between an iSCSI adapter and a target.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To remove a session, run the following command:
esxcli --server=server_name iscsi session remove
The command takes these options:
Option
Description
-A|--adapter=str
The iSCSI adapter name, for example, vmhba34. This option is required.
-s|--isid=str
The ISID of a session to remove. You can find it by listing all session.
-n|--name=str
The iSCSI target name, for example, iqn.X.
What to do next
Rescan the iSCSI adapter.
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Booting from iSCSI SAN
11
When you set up your host to boot from a SAN, your host's boot image is stored on one or more LUNs in
the SAN storage system. When the host starts, it boots from the LUN on the SAN rather than from its local
disk.
You can use boot from the SAN if you do not want to handle maintenance of local storage or have diskless
hardware configurations, such as blade systems.
ESXi supports different methods of booting from the iSCSI SAN.
Table 11‑1. Boot from iSCSI SAN support
Independent Hardware iSCSI
Software iSCSI and Dependent Hardware iSCSI
Configure the iSCSI HBA to boot from the SAN.
For information on configuring the HBA, see
“Configure Independent Hardware iSCSI Adapter
for SAN Boot,” on page 104
Use the network adapter that supports the iBFT. For information,
see “iBFT iSCSI Boot Overview,” on page 105.
This chapter includes the following topics:
n
“General Boot from iSCSI SAN Recommendations,” on page 103
n
“Prepare the iSCSI SAN,” on page 104
n
“Configure Independent Hardware iSCSI Adapter for SAN Boot,” on page 104
n
“iBFT iSCSI Boot Overview,” on page 105
General Boot from iSCSI SAN Recommendations
If you plan to set up and use an iSCSI LUN as the boot device for your host, you need to follow certain
general guidelines.
The following guidelines apply to booting from independent hardware iSCSI and iBFT.
n
Review any vendor recommendations for the hardware you use in your boot configuration.
n
For installation prerequisites and requirements, review vSphere Installation and Setup.
n
Use static IP addresses to reduce the chances of DHCP conflicts.
n
Use different LUNs for VMFS datastores and boot partitions.
n
Configure proper ACLs on your storage system.
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n
The boot LUN should be visible only to the host that uses the LUN. No other host on the SAN
should be permitted to see that boot LUN.
n
If a LUN is used for a VMFS datastore, it can be shared by multiple hosts. ACLs on the storage
systems can allow you to do this.
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n
Configure a diagnostic partition.
n
With independent hardware iSCSI only, you can place the diagnostic partition on the boot LUN. If
you configure the diagnostic partition in the boot LUN, this LUN cannot be shared across multiple
hosts. If a separate LUN is used for the diagnostic partition, it can be shared by multiple hosts.
n
If you boot from SAN using iBFT, you cannot set up a diagnostic partition on a SAN LUN. To
collect your host's diagnostic information, use the vSphere ESXi Dump Collector on a remote
server. For information about the ESXi Dump Collector, see vSphere Installation and Setup and
vSphere Networking.
Prepare the iSCSI SAN
Before you configure your host to boot from an iSCSI LUN, prepare and configure your storage area
network.
Caution If you use scripted installation to install ESXi when booting from a SAN, you must take special
steps to avoid unintended data loss.
Procedure
1
Connect network cables, referring to any cabling guide that applies to your setup.
2
Ensure IP connectivity between your storage system and server.
This includes proper configuration of any routers or switches on your storage network. Storage systems
must be able to ping the iSCSI adapters in your hosts.
3
Configure the storage system.
a
Create a volume (or LUN) on the storage system for your host to boot from.
b
Configure the storage system so that your host has access to the assigned LUN.
This could involve updating ACLs with the IP addresses, iSCSI names, and the CHAP
authentication parameter you use on your host. On some storage systems, in addition to providing
access information for the ESXi host, you must also explicitly associate the assigned LUN with the
host.
c
Ensure that the LUN is presented to the host correctly.
d
Ensure that no other system has access to the configured LUN.
e
Record the iSCSI name and IP addresses of the targets assigned to the host.
You must have this information to configure your iSCSI adapters.
Configure Independent Hardware iSCSI Adapter for SAN Boot
If your ESXi host uses an independent hardware iSCSI adapter, such as QLogic HBA, you need to configure
the adapter to boot from the SAN.
This procedure discusses how to enable the QLogic iSCSI HBA to boot from the SAN. For more information
and more up-to-date details about QLogic adapter configuration settings, see the QLogic web site.
Prerequisites
Because you first need to boot from the VMware installation media, set up your host to boot from CD/DVDROM. To achieve this, change the system boot sequence in your system BIOS setup.
Procedure
1
104
Insert the installation CD/DVD in the CD/DVD-ROM drive and reboot the host.
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2
Use the BIOS to set the host to boot from the CD/DVD-ROM drive first.
3
During server POST, press Crtl+q to enter the QLogic iSCSI HBA configuration menu.
4
Select the I/O port to configure.
By default, the Adapter Boot mode is set to Disable.
5
6
Configure the HBA.
a
From the Fast!UTIL Options menu, select Configuration Settings > Host Adapter Settings.
b
Configure the following settings for your host adapter: initiator IP address, subnet mask, gateway,
initiator iSCSI name, and CHAP (if required).
Configure iSCSI settings.
See “Configure iSCSI Boot Settings,” on page 105.
7
Save your changes and restart the system.
Configure iSCSI Boot Settings
When setting up your ESXi host to boot from iSCSI, you need to configure iSCSI boot settings.
Procedure
1
From the Fast!UTIL Options menu, select Configuration Settings > iSCSI Boot Settings.
2
Before you can set SendTargets, set Adapter Boot mode to Manual.
3
Select Primary Boot Device Settings.
a
Enter the discovery Target IP and Target Port.
b
You can leave the Boot LUN and iSCSI Name fields blank if only one iSCSI target and one LUN
are at the specified address to boot from. Otherwise, you must specify these fields to ensure that
you do not boot from a volume for some other system. After the target storage system is reached,
these fields will be populated after a rescan.
c
Save changes.
4
From the iSCSI Boot Settings menu, select the primary boot device. An auto rescan of the HBA is made
to find new target LUNS.
5
Select the iSCSI target.
Note If more then one LUN exists within the target, you can choose a specific LUN ID by pressing
Enter after you locate the iSCSI device.
6
Return to the Primary Boot Device Setting menu. After the rescan, the Boot LUNand iSCSI Name
fields are populated. Change the value of Boot LUN to the desired LUN ID.
iBFT iSCSI Boot Overview
ESXi hosts can boot from an iSCSI SAN using the software or dependent hardware iSCSI adapters and
network adapters.
To deploy ESXi and boot from the iSCSI SAN, the host must have an iSCSI boot capable network adapter
that supports the iSCSI Boot Firmware Table (iBFT) format. The iBFT is a method of communicating
parameters about the iSCSI boot device to an operating system.
Before installing ESXi and booting from the iSCSI SAN, configure the networking and iSCSI boot parameters
on the network adapter and enable the adapter for the iSCSI boot. Because configuring the network adapter
is vendor specific, review your vendor documentation for instructions.
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When you first boot from iSCSI, the iSCSI boot firmware on your system connects to an iSCSI target. If login
is successful, the firmware saves the networking and iSCSI boot parameters in the iBFT and stores the table
in the system's memory. The system uses this table to configure its own iSCSI connection and networking
and to start up.
The following list describes the iBFT iSCSI boot sequence.
1
When restarted, the system BIOS detects the iSCSI boot firmware on the network adapter.
2
The iSCSI boot firmware uses the preconfigured boot parameters to connect with the specified iSCSI
target.
3
If the connection to the iSCSI target is successful, the iSCSI boot firmware writes the networking and
iSCSI boot parameters in to the iBFT and stores the table in the system memory.
Note The system uses this table to configure its own iSCSI connection and networking and to start up.
4
The BIOS boots the boot device.
5
The VMkernel starts loading and takes over the boot operation.
6
Using the boot parameters from the iBFT, the VMkernel connects to the iSCSI target.
7
After the iSCSI connection is established, the system boots.
iBFT iSCSI Boot Considerations
When you boot the ESXi host from iSCSI using iBFT-enabled network adapters, certain considerations apply.
n
Update your NIC's boot code and iBFT firmware using vendor supplied tools before trying to install
and boot VMware ESXi. Consult vendor documentation and VMware HCL for supported boot code
and iBFT firmware versions for VMware ESXi iBFT boot.
n
The iBFT iSCSI boot does not support failover for the iBFT-enabled network adapters.
n
After you set up your host to boot from iBFT iSCSI, the following restrictions apply:
n
You cannot disable the software iSCSI adapter. If the iBFT configuration is present in the BIOS, the
host re-enables the software iSCSI adapter during each reboot.
Note If you do not use the iBFT-enabled network adapter for the iSCSI boot and do not want the
software iSCSI adapter to be always enabled, remove the iBFT configuration from the network
adapter.
n
You cannot remove the iBFT iSCSI boot target using the vSphere Web Client. The target appears on
the list of adapter static targets.
Configuring iBFT Boot from SAN
You can boot from the iSCSI SAN using the software iSCSI adapter or a dependent hardware iSCSI adapter
and a network adapter. The network adapter must support iBFT.
When you set up your host to boot with iBFT, you perform a number of tasks.
1
Configure iSCSI Boot Parameters on page 107
To begin an iSCSI boot process, a network adapter on your host must have a specially configured iSCSI
boot firmware. When you configure the firmware, you specify the networking and iSCSI parameters
and enable the adapter for the iSCSI boot.
2
Change Boot Sequence in BIOS on page 107
When setting up your host to boot from iBFT iSCSI, change the boot sequence to force your host to
boot in an appropriate order.
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3
Install ESXi to iSCSI Target on page 107
When setting up your host to boot from iBFT iSCSI, install the ESXi image to the target LUN.
4
Boot ESXi from iSCSI Target on page 108
After preparing the host for an iBFT iSCSI boot and copying the ESXi image to the iSCSI target,
perform the actual boot.
Configure iSCSI Boot Parameters
To begin an iSCSI boot process, a network adapter on your host must have a specially configured iSCSI boot
firmware. When you configure the firmware, you specify the networking and iSCSI parameters and enable
the adapter for the iSCSI boot.
Configuration on the network adapter can be dynamic or static. If you use the dynamic configuration, you
indicate that all target and initiator boot parameters are acquired using DHCP. For the static configuration,
you manually enter data that includes your host's IP address and initiator IQN, and the target parameters.
Procedure
u
On the network adapter that you use for the boot from iSCSI, specify networking and iSCSI parameters.
Because configuring the network adapter is vendor specific, review your vendor documentation for
instructions.
Change Boot Sequence in BIOS
When setting up your host to boot from iBFT iSCSI, change the boot sequence to force your host to boot in
an appropriate order.
Change the BIOS boot sequence to the following sequence:
n
iSCSI
n
DVD-ROM
Because changing the boot sequence in the BIOS is vendor specific, refer to vendor documentation for
instructions. The following sample procedure explains how to change the boot sequence on a Dell host with
a Broadcom network adapter.
Procedure
1
Turn on the host.
2
During Power-On Self-Test (POST), press F2 to enter the BIOS Setup.
3
In the BIOS Setup, select Boot Sequence and press Enter.
4
In the Boot Sequence menu, arrange the bootable items so that iSCSI precedes the DVD-ROM.
5
Press Esc to exit the Boot Sequence menu.
6
Press Esc to exit the BIOS Setup.
7
Select Save Changes and click Exit to exit the BIOS Setup menu.
Install ESXi to iSCSI Target
When setting up your host to boot from iBFT iSCSI, install the ESXi image to the target LUN.
Prerequisites
n
Configure iSCSI boot firmware on your boot NIC to point to the target LUN that you want to use as the
boot LUN.
n
Change the boot sequence in the BIOS so that iSCSI precedes the DVD-ROM.
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n
If you use Broadcom adapters, set Boot to iSCSI target to Disabled.
Procedure
1
Insert the installation media in the CD/DVD-ROM drive and restart the host.
2
When the installer starts, follow the typical installation procedure.
3
When prompted, select the iSCSI LUN as the installation target.
The installer copies the ESXi boot image to the iSCSI LUN.
4
After the system restarts, remove the installation DVD.
Boot ESXi from iSCSI Target
After preparing the host for an iBFT iSCSI boot and copying the ESXi image to the iSCSI target, perform the
actual boot.
Prerequisites
n
Configure the iSCSI boot firmware on your boot NIC to point to the boot LUN.
n
Change the boot sequence in the BIOS so that iSCSI precedes the boot device.
n
If you use Broadcom adapters, set Boot to iSCSI target to Enabled
Procedure
1
Restart the host.
The host boots from the iSCSI LUN using iBFT data. During the first boot, the iSCSI initialization script
sets up default networking. The network setup is persistent after subsequent reboots.
2
(Optional) Adjust networking configuration using the vSphere Web Client.
Networking Best Practices
To boot the ESXi host from iSCSI using iBFT, you must properly configure networking.
To achieve greater security and better performance, have redundant network adapters on the host.
How you set up all the network adapters depends on whether your environment uses shared or isolated
networks for the iSCSI traffic and host management traffic.
Shared iSCSI and Management Networks
Configure the networking and iSCSI parameters on the first network adapter on the host. After the host
boots, you can add secondary network adapters to the default port group.
Isolated iSCSI and Management Networks
When you configure isolated iSCSI and management networks, follow these guidelines to avoid bandwidth
problems.
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n
Your isolated networks must be on different subnets.
n
If you use VLANs to isolate the networks, they must have different subnets to ensure that routing tables
are properly set up.
n
VMware recommends that you configure the iSCSI adapter and target to be on the same subnet. If you
set up the iSCSI adapter and target on different subnets, the following restrictions apply:
n
The default VMkernel gateway must be able to route both the management and iSCSI traffic.
n
After you boot your host, you can use the iBFT-enabled network adapter only for iBFT. You cannot
use the adapter for other iSCSI traffic.
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n
Use the first physical network adapter for the management network.
n
Use the second physical network adapter for the iSCSI network. Make sure to configure the iBFT.
n
After the host boots, you can add secondary network adapters to both the management and iSCSI
networks.
Change iBFT iSCSI Boot Settings
If settings, such as the IQN name, IP address, and so on, change on the iSCSI storage or your host, update
the iBFT. This task assumes that the boot LUN and the data stored on the LUN remain intact.
Procedure
1
Shut down the ESXi host.
2
Change iSCSI storage settings.
3
Update the iBFT on the host with the new settings.
4
Restart the host.
The host boots using the new information stored in the iBFT.
Troubleshooting iBFT iSCSI Boot
The topics in this section help you to identify and solve problems you might encounter when using iBFT
iSCSI boot.
Loss of System's Gateway Causes Loss of Network Connectivity
You lose network connectivity when you delete a port group associated with the iBFT network adapter.
Problem
A loss of network connectivity occurs after you delete a port group.
Cause
When you specify a gateway in the iBFT-enabled network adapter during ESXi installation, this gateway
becomes the system's default gateway. If you delete the port group associated with the network adapter, the
system's default gateway is lost. This action causes the loss of network connectivity.
Solution
Do not set an iBFT gateway unless it is required. If the gateway is required, after installation, manually set
the system's default gateway to the one that the management network uses.
Changing iSCSI Boot Parameters Causes ESXi to Boot in Stateless Mode
Changing iSCSI boot parameters on the network adapter after the first boot does not update the iSCSI and
networking configuration on the ESXi host.
Problem
If you change the iSCSI boot parameters on the network adapter after the first ESXi boot from iSCSI, the host
will boot in a stateless mode.
Cause
The firmware uses the updated boot configuration and is able to connect to the iSCSI target and load the
ESXi image. However, when loaded, the system does not pick up the new parameters, but continues to use
persistent networking and iSCSI parameters from the previous boot. As a result, the host cannot connect to
the target and boots in the stateless mode.
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Solution
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1
Use the vSphere Web Client to connect to the ESXi host.
2
Re-configure the iSCSI and networking on the host to match the iBFT parameters.
3
Perform a rescan.
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Best Practices for iSCSI Storage
12
When using ESXi with the iSCSI SAN, follow best practices that VMware offers to avoid problems.
Check with your storage representative if your storage system supports Storage API - Array Integration
hardware acceleration features. If it does, refer to your vendor documentation for information on how to
enable hardware acceleration support on the storage system side. For more information, see Chapter 23,
“Storage Hardware Acceleration,” on page 277.
This chapter includes the following topics:
n
“Preventing iSCSI SAN Problems,” on page 111
n
“Optimizing iSCSI SAN Storage Performance,” on page 112
n
“Checking Ethernet Switch Statistics,” on page 115
Preventing iSCSI SAN Problems
When using ESXi in conjunction with a SAN, you must follow specific guidelines to avoid SAN problems.
You should observe these tips for avoiding problems with your SAN configuration:
n
Place only one VMFS datastore on each LUN. Multiple VMFS datastores on one LUN is not
recommended.
n
Do not change the path policy the system sets for you unless you understand the implications of
making such a change.
n
Document everything. Include information about configuration, access control, storage, switch, server
and iSCSI HBA configuration, software and firmware versions, and storage cable plan.
n
Plan for failure:
n
Make several copies of your topology maps. For each element, consider what happens to your SAN
if the element fails.
n
Cross off different links, switches, HBAs and other elements to ensure you did not miss a critical
failure point in your design.
n
Ensure that the iSCSI HBAs are installed in the correct slots in the ESXi host, based on slot and bus
speed. Balance PCI bus load among the available busses in the server.
n
Become familiar with the various monitor points in your storage network, at all visibility points,
including ESXi performance charts, Ethernet switch statistics, and storage performance statistics.
n
Be cautious when changing IDs of the LUNs that have VMFS datastores being used by your host. If you
change the ID, virtual machines running on the VMFS datastore will fail.
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If there are no running virtual machines on the VMFS datastore, after you change the ID of the LUN,
you must use rescan to reset the ID on your host. For information on using rescan, see “Storage Rescan
Operations,” on page 120.
n
If you need to change the default iSCSI name of your iSCSI adapter, make sure the name you enter is
worldwide unique and properly formatted. To avoid storage access problems, never assign the same
iSCSI name to different adapters, even on different hosts.
Optimizing iSCSI SAN Storage Performance
Several factors contribute to optimizing a typical SAN environment.
If the network environment is properly configured, the iSCSI components provide adequate throughput and
low enough latency for iSCSI initiators and targets. If the network is congested and links, switches or routers
are saturated, iSCSI performance suffers and might not be adequate for ESXi environments.
Storage System Performance
Storage system performance is one of the major factors contributing to the performance of the entire iSCSI
environment.
If issues occur with storage system performance, consult your storage system vendor’s documentation for
any relevant information.
When you assign LUNs, remember that you can access each shared LUN through a number of hosts, and
that a number of virtual machines can run on each host. One LUN used by the ESXi host can service I/O
from many different applications running on different operating systems. Because of this diverse workload,
the RAID group that contains the ESXi LUNs should not include LUNs that other hosts use that are not
running ESXi for I/O intensive applications.
Enable read caching and write caching.
Load balancing is the process of spreading server I/O requests across all available SPs and their associated
host server paths. The goal is to optimize performance in terms of throughput (I/O per second, megabytes
per second, or response times).
SAN storage systems require continual redesign and tuning to ensure that I/O is load balanced across all
storage system paths. To meet this requirement, distribute the paths to the LUNs among all the SPs to
provide optimal load balancing. Close monitoring indicates when it is necessary to manually rebalance the
LUN distribution.
Tuning statically balanced storage systems is a matter of monitoring the specific performance statistics (such
as I/O operations per second, blocks per second, and response time) and distributing the LUN workload to
spread the workload across all the SPs.
Server Performance with iSCSI
You must consider several factors to ensure optimal server performance.
Each server application must have access to its designated storage with the following conditions:
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n
High I/O rate (number of I/O operations per second)
n
High throughput (megabytes per second)
n
Minimal latency (response times)
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Because each application has different requirements, you can meet these goals by choosing an appropriate
RAID group on the storage system. To achieve performance goals, perform the following tasks:
n
Place each LUN on a RAID group that provides the necessary performance levels. Pay attention to the
activities and resource utilization of other LUNS in the assigned RAID group. A high-performance
RAID group that has too many applications doing I/O to it might not meet performance goals required
by an application running on the ESXi host.
n
Provide each server with a sufficient number of network adapters or iSCSI hardware adapters to allow
maximum throughput for all the applications hosted on the server for the peak period. I/O spread
across multiple ports provides higher throughput and less latency for each application.
n
To provide redundancy for software iSCSI, make sure the initiator is connected to all network adapters
used for iSCSI connectivity.
n
When allocating LUNs or RAID groups for ESXi systems, multiple operating systems use and share that
resource. As a result, the performance required from each LUN in the storage subsystem can be much
higher if you are working with ESXi systems than if you are using physical machines. For example, if
you expect to run four I/O intensive applications, allocate four times the performance capacity for the
ESXi LUNs.
n
When using multiple ESXi systems in conjunction with vCenter Server, the performance needed from
the storage subsystem increases correspondingly.
n
The number of outstanding I/Os needed by applications running on an ESXi system should match the
number of I/Os the SAN can handle.
Network Performance
A typical SAN consists of a collection of computers connected to a collection of storage systems through a
network of switches. Several computers often access the same storage.
Single Ethernet Link Connection to Storage shows several computer systems connected to a storage system
through an Ethernet switch. In this configuration, each system is connected through a single Ethernet link to
the switch, which is also connected to the storage system through a single Ethernet link. In most
configurations, with modern switches and typical traffic, this is not a problem.
Figure 12‑1. Single Ethernet Link Connection to Storage
When systems read data from storage, the maximum response from the storage is to send enough data to fill
the link between the storage systems and the Ethernet switch. It is unlikely that any single system or virtual
machine gets full use of the network speed, but this situation can be expected when many systems share one
storage device.
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When writing data to storage, multiple systems or virtual machines might attempt to fill their links. As
Dropped Packets shows, when this happens, the switch between the systems and the storage system has to
drop data. This happens because, while it has a single connection to the storage device, it has more traffic to
send to the storage system than a single link can carry. In this case, the switch drops network packets
because the amount of data it can transmit is limited by the speed of the link between it and the storage
system.
Figure 12‑2. Dropped Packets
1 Gbit
1 Gbit
1 Gbit
dropped packets
Recovering from dropped network packets results in large performance degradation. In addition to time
spent determining that data was dropped, the retransmission uses network bandwidth that could otherwise
be used for current transactions.
iSCSI traffic is carried on the network by the Transmission Control Protocol (TCP). TCP is a reliable
transmission protocol that ensures that dropped packets are retried and eventually reach their destination.
TCP is designed to recover from dropped packets and retransmits them quickly and seamlessly. However,
when the switch discards packets with any regularity, network throughput suffers significantly. The
network becomes congested with requests to resend data and with the resent packets, and less data is
actually transferred than in a network without congestion.
Most Ethernet switches can buffer, or store, data and give every device attempting to send data an equal
chance to get to the destination. This ability to buffer some transmissions, combined with many systems
limiting the number of outstanding commands, allows small bursts from several systems to be sent to a
storage system in turn.
If the transactions are large and multiple servers are trying to send data through a single switch port, a
switch's ability to buffer one request while another is transmitted can be exceeded. In this case, the switch
drops the data it cannot send, and the storage system must request retransmission of the dropped packet.
For example, if an Ethernet switch can buffer 32KB on an input port, but the server connected to it thinks it
can send 256KB to the storage device, some of the data is dropped.
Most managed switches provide information on dropped packets, similar to the following:
*: interface is up
IHQ: pkts in input hold queue
OHQ: pkts in output hold queue
RXBS: rx rate (bits/sec)
IQD: pkts dropped from input queue
OQD: pkts dropped from output queue
RXPS: rx rate (pkts/sec)
TXBS: tx rate (bits/sec)
TRTL: throttle count
TXPS: tx rate (pkts/sec)
Table 12‑1. Sample Switch Information
Interface
IHQ
IQD
OHQ
OQD
RXBS
RXPS
TXBS
TXPS
TRTL
*
GigabitEt
hernet0/1
3
9922
0
0
47630300
0
62273
47784000
0
63677
0
In this example from a Cisco switch, the bandwidth used is 476303000 bits/second, which is less than half of
wire speed. In spite of this, the port is buffering incoming packets and has dropped quite a few packets. The
final line of this interface summary indicates that this port has already dropped almost 10,000 inbound
packets in the IQD column.
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Configuration changes to avoid this problem involve making sure several input Ethernet links are not
funneled into one output link, resulting in an oversubscribed link. When a number of links transmitting near
capacity are switched to a smaller number of links, oversubscription is a possibility.
Generally, applications or systems that write a lot of data to storage, such as data acquisition or transaction
logging systems, should not share Ethernet links to a storage device. These types of applications perform
best with multiple connections to storage devices.
Multiple Connections from Switch to Storage shows multiple connections from the switch to the storage.
Figure 12‑3. Multiple Connections from Switch to Storage
1 Gbit
1 Gbit
1 Gbit
1 Gbit
Using VLANs or VPNs does not provide a suitable solution to the problem of link oversubscription in
shared configurations. VLANs and other virtual partitioning of a network provide a way of logically
designing a network, but do not change the physical capabilities of links and trunks between switches.
When storage traffic and other network traffic end up sharing physical connections, as they would with a
VPN, the possibility for oversubscription and lost packets exists. The same is true of VLANs that share
interswitch trunks. Performance design for a SANs must take into account the physical limitations of the
network, not logical allocations.
Checking Ethernet Switch Statistics
Many Ethernet switches provide different methods for monitoring switch health.
Switches that have ports operating near maximum throughput much of the time do not provide optimum
performance. If you have ports in your iSCSI SAN running near the maximum, reduce the load. If the port is
connected to an ESXi system or iSCSI storage, you can reduce the load by using manual load balancing.
If the port is connected between multiple switches or routers, consider installing additional links between
these components to handle more load. Ethernet switches also commonly provide information about
transmission errors, queued packets, and dropped Ethernet packets. If the switch regularly reports any of
these conditions on ports being used for iSCSI traffic, performance of the iSCSI SAN will be poor.
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Managing Storage Devices
13
Manage local and networked storage device that your ESXi host has access to.
This chapter includes the following topics:
n
“Storage Device Characteristics,” on page 117
n
“Understanding Storage Device Naming,” on page 119
n
“Storage Rescan Operations,” on page 120
n
“Identifying Device Connectivity Problems,” on page 122
n
“Edit Configuration File Parameters,” on page 127
n
“Enable or Disable the Locator LED on Storage Devices,” on page 128
n
“Erase Storage Devices,” on page 128
Storage Device Characteristics
You can display all storage devices or LUNs available to the host, including all local and networked devices.
If you use third-party multipathing plug-ins, the storage devices available through the plug-ins also appear
on the list.
For each storage adapter, you can display a separate list of storage devices available for this adapter.
Generally, when you review storage devices, you see the following information.
Table 13‑1. Storage Device Information
Storage Device Information
Description
Name
Also called Display Name. It is a name that the ESXi host assigns to the device based on
the storage type and manufacturer. You can change this name to a name of your choice.
Identifier
A universally unique identifier that is intrinsic to the device.
Operational State
Indicates whether the device is mounted or unmounted. For details, see “Detach
Storage Devices,” on page 124.
LUN
Logical Unit Number (LUN) within the SCSI target. The LUN number is provided by
the storage system. If a target has only one LUN, the LUN number is always zero (0).
Type
Type of device, for example, disk or CD-ROM.
Drive Type
Information about whether the device is a flash drive or a regular HDD drive. For
information about flash drives, see Chapter 14, “Working with Flash Devices,” on
page 129.
Transport
Transportation protocol your host uses to access the device. The protocol depends on
the type of storage being used. See “Types of Physical Storage,” on page 14.
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Table 13‑1. Storage Device Information (Continued)
Storage Device Information
Description
Capacity
Total capacity of the storage device.
Owner
The plug-in, such as the NMP or a third-party plug-in, that the host uses to manage
paths to the storage device. For details, see “Managing Multiple Paths,” on page 186.
Hardware Acceleration
Information about whether the storage device assists the host with virtual machine
management operations. The status can be Supported, Not Supported, or Unknown.
For details, see Chapter 23, “Storage Hardware Acceleration,” on page 277.
Sector Format
Indicates whether the device uses a traditional, 512n, or advanced sector format, such as
512e. For more information, see “Storage Device Formats and VMFS Datastores,” on
page 144.
Location
A path to the storage device in the /vmfs/devices/ directory.
Partition Format
A partition scheme used by the storage device. It could be of a master boot record
(MBR) or GUID partition table (GPT) format. The GPT devices can support datastores
greater than 2 TB. For more information, see “Storage Device Formats and VMFS
Datastores,” on page 144.
Partitions
Primary and logical partitions, including a VMFS datastore, if configured.
Multipathing Policies (VMFS
datastores)
Path Selection Policy and Storage Array Type Policy the host uses to manage paths to
storage. For more information, see Chapter 17, “Understanding Multipathing and
Failover,” on page 181.
Paths (VMFS datastores)
Paths used to access storage and their status.
Display Storage Devices for a Host
Display all storage devices available to a host. If you use any third-party multipathing plug-ins, the storage
devices available through the plug-ins also appear on the list.
The Storage Devices view allows you to list the hosts' storage devices, analyze their information, and modify
properties.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
All storage devices available to the host are listed in the Storage Devices table.
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4
To view details for a specific device, select the device from the list.
5
Use tabs under Device Details to access additional information and modify properties for the selected
device.
Tab
Description
Properties
View device properties and characteristics. View and modify multipathing
policies for the device.
Paths
Display paths available for the device. Disable or enable a selected path.
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Display Storage Devices for an Adapter
Display a list of storage devices accessible through a specific storage adapter on the host.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters.
All storage adapters installed on the host are listed in the Storage Adapters table.
4
Select the adapter from the list and click the Devices tab.
Storage devices that the host can access through the adapter are displayed.
Understanding Storage Device Naming
Each storage device, or LUN, is identified by several names.
Device Identifiers
Depending on the type of storage, the ESXi host uses different algorithms and conventions to generate an
identifier for each storage device.
SCSI INQUIRY
identifiers.
The host uses the SCSI INQUIRY command to query a storage device and
uses the resulting data, in particular the Page 83 information, to generate a
unique identifier. Device identifiers that are based on Page 83 are unique
across all hosts, persistent, and have one of the following formats:
n
naa.number
n
t10.number
n
eui.number
These formats follow the T10 committee standards. See the SCSI-3
documentation on the T10 committee Web site.
Path-based identifier.
When the device does not provide the Page 83 information, the host
generates an mpx.path name, where path represents the first path to the
device, for example, mpx.vmhba1:C0:T1:L3. This identifier can be used in the
same way as the SCSI INQUIRY identifies.
The mpx. identifier is created for local devices on the assumption that their
path names are unique. However, this identifier is neither unique nor
persistent and could change after every boot.
Typically, the path to the device has the following format:
vmhbaAdapter:CChannel:TTarget:LLUN
n
vmhbaAdapter is the name of the storage adapter. The name refers to the
physical adapter on the host, not to the SCSI controller used by the
virtual machines.
n
CChannel is the storage channel number.
Software iSCSI adapters and dependent hardware adapters use the
channel number to show multiple paths to the same target.
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n
TTarget is the target number. Target numbering is determined by the
host and might change if the mappings of targets visible to the host
change. Targets that are shared by different hosts might not have the
same target number.
n
LLUN is the LUN number that shows the position of the LUN within the
target. The LUN number is provided by the storage system. If a target
has only one LUN, the LUN number is always zero (0).
For example, vmhba1:C0:T3:L1 represents LUN1 on target 3 accessed through
the storage adapter vmhba1 and channel 0.
Legacy Identifier
In addition to the SCSI INQUIRY or mpx. identifiers, for each device, ESXi generates an alternative legacy
name. The identifier has the following format:
vml.number
The legacy identifier includes a series of digits that are unique to the device and can be derived in part from
the Page 83 information, if it is available. For nonlocal devices that do not support Page 83 information, the
vml. name is used as the only available unique identifier.
Example: Displaying Device Names in the vSphere CLI
You can use the esxcli --server=server_name storage core device list command to display all device
names in the vSphere CLI. The output is similar to the following example:
# esxcli --server=server_name storage core device list
naa.number
Display Name: DGC Fibre Channel Disk(naa.number)
...
Other UIDs:vml.number
Rename Storage Devices
You can change the display name of a storage device. The display name is assigned by the ESXi host based
on the storage type and manufacturer.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
Select the device to rename and click Rename.
5
Change the device name to a friendly name.
Storage Rescan Operations
When you perform storage management tasks or make changes in the SAN configuration, you might need
to rescan your storage.
When you perform VMFS datastore management operations, such as creating a VMFS datastore or RDM,
adding an extent, and increasing or deleting a VMFS datastore, your host or the vCenter Server
automatically rescans and updates your storage. You can disable the automatic rescan feature by turning off
the Host Rescan Filter. See “Turn off Storage Filters,” on page 172.
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In certain cases, you need to perform a manual rescan. You can rescan all storage available to your host or to
all hosts in a folder, cluster, and data center.
If the changes you make are isolated to storage connected through a specific adapter, perform a rescan for
this adapter.
Perform the manual rescan each time you make one of the following changes.
n
Zone a new disk array on a SAN.
n
Create new LUNs on a SAN.
n
Change the path masking on a host.
n
Reconnect a cable.
n
Change CHAP settings (iSCSI only).
n
Add or remove discovery or static addresses (iSCSI only).
n
Add a single host to the vCenter Server after you have edited or removed from the vCenter Server a
datastore shared by the vCenter Server hosts and the single host.
Important If you rescan when a path is unavailable, the host removes the path from the list of paths to the
device. The path reappears on the list as soon as it becomes available and starts working again.
Perform Storage Rescan
When you make changes in your SAN configuration, you might need to rescan your storage. You can rescan
all storage available to your host, cluster, or data center. If the changes you make are isolated to storage
accessed through a specific host, perform the rescan for only this host.
Procedure
1
In the vSphere Web Client object navigator, browse to a host, a cluster, a data center, or a folder that
contains hosts.
2
From the right-click menu, select Storage > Rescan Storage .
3
Specify extent of rescan.
Option
Description
Scan for New Storage Devices
Rescan all adapters to discover new storage devices. If new devices are
discovered, they appear in the device list.
Scan for New VMFS Volumes
Rescan all storage devices to discover new datastores that have been added
since the last scan. Any new datastores appear in the datastore list.
Perform Adapter Rescan
When you make changes in your SAN configuration and these changes are isolated to storage accessed
through a specific adapter, perform rescan for only this adapter.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Adapters, and select the adapter to rescan from the list.
4
Click the Rescan Adapter icon.
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Change the Number of Scanned Storage Devices
The range of scanned LUN IDs for an ESXi host can be from 0 to 16,383. ESXi ignores LUN IDs greater than
16,383. The configurable Disk.MaxLUN parameter controls the range of scanned LUN ID range. The parameter
has a default value of 1024.
The Disk.MaxLUN parameter also determines how many LUNs the SCSI scan code attempts to discover using
individual INQUIRY commands if the SCSI target does not support direct discovery using REPORT_LUNS.
You can modify the Disk.MaxLUN parameter depending on your needs. For example, if your environment has
a smaller number of storage devices with LUN IDs from 1 through 100, set the value to 101. As a result, you
can improve device discovery speed on targets that do not support REPORT_LUNS. Lowering the value can
shorten the rescan time and boot time. However, the time to rescan storage devices might also depend on
other factors, including the type of the storage system and the load on the storage system.
In other cases, you might need to increase the value if your environment uses LUN IDs that are greater than
1023.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
In the Advanced System Settings table, select Disk.MaxLUN and click the Edit icon.
5
Change the existing value to the value of your choice, and click OK.
The value you enter specifies the LUN ID that is after the last one you want to discover.
For example, to discover LUN IDs from 1 through 100, set Disk.MaxLUN to 101.
Identifying Device Connectivity Problems
When your ESXi host experiences a problem while connecting to a storage device, the host treats the
problem as permanent or temporary depending on certain factors.
Storage connectivity problems are caused by a variety of reasons. Although ESXi cannot always determine
the reason for a storage device or its paths being unavailable, the host differentiates between a permanent
device loss (PDL) state of the device and a transient all paths down (APD) state of storage.
Permanent Device Loss
(PDL)
A condition that occurs when a storage device permanently fails or is
administratively removed or excluded. It is not expected to become available.
When the device becomes permanently unavailable, ESXi receives
appropriate sense codes or a login rejection from storage arrays, and is able
to recognize that the device is permanently lost.
All Paths Down (APD)
A condition that occurs when a storage device becomes inaccessible to the
host and no paths to the device are available. ESXi treats this as a transient
condition because typically the problems with the device are temporary and
the device is expected to become available again.
Detecting PDL Conditions
A storage device is considered to be in the permanent device loss (PDL) state when it becomes permanently
unavailable to your ESXi host.
Typically, the PDL condition occurs when a device is unintentionally removed, or its unique ID changes, or
when the device experiences an unrecoverable hardware error.
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When the storage array determines that the device is permanently unavailable, it sends SCSI sense codes to
the ESXi host. The sense codes allow your host to recognize that the device has failed and register the state
of the device as PDL. The sense codes must be received on all paths to the device for the device to be
considered permanently lost.
After registering the PDL state of the device, the host stops attempts to reestablish connectivity or to issue
commands to the device to avoid becoming blocked or unresponsive.
The vSphere Web Client displays the following information for the device:
n
The operational state of the device changes to Lost Communication.
n
All paths are shown as Dead.
n
Datastores on the device are grayed out.
The host automatically removes the PDL device and all paths to the device if no open connections to the
device exist, or after the last connection closes. You can disable the automatic removal of paths by setting the
advanced host parameter Disk.AutoremoveOnPDL to 0. See “Set Advanced Host Attributes,” on page 179.
If the device returns from the PDL condition, the host can discover it, but treats it as a new device. Data
consistency for virtual machines on the recovered device is not guaranteed.
Note The host cannot detect PDL conditions and continues to treat the device connectivity problems as
APD when a storage device permanently fails in a way that does not return appropriate SCSI sense codes or
iSCSI login rejection.
Permanent Device Loss and SCSI Sense Codes
The following VMkernel log example of a SCSI sense code indicates that the device is in the PDL state.
H:0x0 D:0x2 P:0x0 Valid sense data: 0x5 0x25 0x0 or Logical Unit Not Supported
For information about SCSI sense codes, see Troubleshooting Storage in vSphere Troubleshooting.
Permanent Device Loss and iSCSI
In the case of iSCSI arrays with a single LUN per target, PDL is detected through iSCSI login failure. An
iSCSI storage array rejects your host's attempts to start an iSCSI session with a reason Target Unavailable.
As with the sense codes, this response must be received on all paths for the device to be considered
permanently lost.
Permanent Device Loss and Virtual Machines
After registering the PDL state of the device, the host terminates all I/O from virtual machines. vSphere HA
can detect PDL and restart failed virtual machines. For more information, see “Device Connectivity
Problems and High Availability,” on page 127.
Performing Planned Storage Device Removal
When a storage device is malfunctioning, you can avoid permanent device loss (PDL) conditions or all paths
down (APD) conditions and perform a planned removal and reconnection of a storage device.
Planned device removal is an intentional disconnection of a storage device. You might also plan to remove a
device for such reasons as upgrading your hardware or reconfiguring your storage devices. When you
perform an orderly removal and reconnection of a storage device, you complete a number of tasks.
1
Migrate virtual machines from the device you plan to detach.
See the vCenter Server and Host Management documentation.
2
Unmount the datastore deployed on the device.
See “Unmount Datastores,” on page 167.
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3
Detach the storage device.
See “Detach Storage Devices,” on page 124.
4
For an iSCSI device with a single LUN per target, delete the static target entry from each iSCSI HBA
that has a path to the storage device.
See “Remove Dynamic or Static iSCSI Targets,” on page 94.
5
Perform any necessary reconfiguration of the storage device by using the array console.
6
Reattach the storage device.
See “Attach Storage Devices,” on page 124.
7
Mount the datastore and restart the virtual machines. See “Mount Datastores,” on page 168.
Detach Storage Devices
Safely detach a storage device from your host.
You might need to detach the device to make it inaccessible to your host, when, for example, you perform a
hardware upgrade on the storage side.
Prerequisites
n
The device does not contain any datastores.
n
No virtual machines use the device as an RDM disk.
n
The device does not contain a diagnostic partition or a scratch partition.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
Select the device to detach and click the Detach icon.
The device becomes inaccessible. The operational state of the device changes to Unmounted.
What to do next
If multiple hosts share the device, detach the device from each host.
Attach Storage Devices
Reattach a storage device that you previously detached.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
Select the detached storage device and click the Attach icon.
The device becomes accessible.
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Recovering From PDL Conditions
An unplanned permanent device loss (PDL) condition occurs when a storage device becomes permanently
unavailable without being properly detached from the ESXi host.
The following items in the vSphere Web Client indicate that the device is in the PDL state:
n
The datastore deployed on the device is unavailable.
n
Operational state of the device changes to Lost Communication.
n
All paths are shown as Dead.
n
A warning about the device being permanently inaccessible appears in the VMkernel log file.
To recover from the unplanned PDL condition and remove the unavailable device from the host, you need to
perform a number of tasks.
1
Power off and unregister all virtual machines that are running on the datastore affected by the PDL
condition.
2
Unmount the datastore.
See “Unmount Datastores,” on page 167.
3
Perform a rescan on all ESXi hosts that had access to the device.
See “Perform Storage Rescan,” on page 121.
Note If the rescan is not successful and the host continues to list the device, some pending I/O or active
references to the device might still exist. Check for virtual machines, templates, ISO images, raw device
mappings, and so on that might still have an active reference to the device or datastore.
Handling Transient APD Conditions
A storage device is considered to be in the all paths down (APD) state when it becomes unavailable to your
ESXi host for an unspecified period of time.
The reasons for an APD state can be, for example, a failed switch or a disconnected storage cable.
In contrast with the permanent device loss (PDL) state, the host treats the APD state as transient and expects
the device to be available again.
The host indefinitely continues to retry issued commands in an attempt to reestablish connectivity with the
device. If the host's commands fail the retries for a prolonged period of time, the host and its virtual
machines might be at risk of having performance problems and potentially becoming unresponsive.
To avoid these problems, your host uses a default APD handling feature. When a device enters the APD
state, the system immediately turns on a timer and allows your host to continue retrying nonvirtual machine
commands for a limited time period.
By default, the APD timeout is set to 140 seconds, which is typically longer than most devices need to
recover from a connection loss. If the device becomes available within this time, the host and its virtual
machine continue to run without experiencing any problems.
If the device does not recover and the timeout ends, the host stops its attempts at retries and terminates any
nonvirtual machine I/O. Virtual machine I/O will continue retrying. The vSphere Web Client displays the
following information for the device with the expired APD timeout:
n
The operational state of the device changes to Dead or Error.
n
All paths are shown as Dead.
n
Datastores on the device are dimmed.
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Even though the device and datastores are unavailable, virtual machines remain responsive. You can power
off the virtual machines or migrate them to a different datastore or host.
If later one or more device paths becomes operational, subsequent I/O to the device is issued normally and
all special APD treatment ends.
Disable Storage APD Handling
The storage all paths down (APD) handling on your ESXi host is enabled by default. When it is enabled, the
host continues to retry nonvirtual machine I/O commands to a storage device in the APD state for a limited
time period. When the time period expires, the host stops its retry attempts and terminates any nonvirtual
machine I/O. You can disable the APD handling feature on your host.
If you disable the APD handling, the host will indefinitely continue to retry issued commands in an attempt
to reconnect to the APD device. Continuing to retry is the same behavior as in ESXi version 5.0. This
behavior might cause virtual machines on the host to exceed their internal I/O timeout and become
unresponsive or fail. The host might become disconnected from vCenter Server.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
In the Advanced System Settings table, select the Misc.APDHandlingEnable parameter and click the
Edit icon.
5
Change the value to 0.
If you disabled the APD handling, you can reenable it when a device enters the APD state. The internal APD
handling feature turns on immediately and the timer starts with the current timeout value for each device in
APD.
Change Timeout Limits for Storage APD
The timeout parameter controls how many seconds the ESXi host must retry the I/O commands to a storage
device in an all paths down (APD) state. You can change the default timeout value.
The timeout period begins immediately after the device enters the APD state. After the timeout ends, the
host marks the APD device as unreachable. The host stops its attempts to retry any I/O that is not coming
from virtual machines. The host continues to retry virtual machine I/O.
By default, the timeout parameter on your host is set to 140 seconds. You can increase the value of the
timeout if, for example, storage devices connected to your ESXi host take longer than 140 seconds to recover
from a connection loss.
Note If you change the timeout parameter after the device becomes unavailable, the change does not take
effect for that particular APD incident.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
In the Advanced System Settings table, select the Misc.APDTimeout parameter and click the Edit icon.
5
Change the default value.
You can enter a value between 20 and 99999 seconds.
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Check the Connection Status of a Storage Device
Use the esxcli command to verify the connection status of a particular storage device.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Run the esxcli --server=server_name storage core device list -d=device_ID command.
2
Check the connection status in the Status: field.
n
on - Device is connected.
n
dead - Device has entered the APD state. The APD timer starts.
n
dead timeout - The APD timeout has expired.
n
not connected - Device is in the PDL state.
Device Connectivity Problems and High Availability
When a device enters a Permanent Device Loss (PDL) or an All Paths Down (APD) state, vSphere High
Availability (HA) can detect connectivity problems and provide automated recovery for affected virtual
machines.
vSphere HA uses VM Component Protection (VMCP) to protect virtual machines running on a host in a
vSphere HA cluster against accessibility failures. For more information about VMCP and how to configure
responses for datastores and virtual machines when an APD or PDL condition occurs, see the vSphere
Availability documentation.
Edit Configuration File Parameters
You can change or add virtual machine configuration parameters when instructed by a VMware technical
support representative, or if you see VMware documentation that instructs you to add or change a
parameter to fix a problem with your system.
Important Changing or adding parameters when a system does not have problems might lead to
decreased system performance and instability.
The following conditions apply:
n
To change a parameter, you change the existing value for the keyword/value pair. For example, if you
start with the keyword/value pair, keyword/value, and change it to keyword/value2, the result is
keyword=value2.
n
You cannot delete a configuration parameter entry.
Caution You must assign a value to configuration parameter keywords. If you do not assign a value, the
keyword can return a value of 0, false, or disable, which can result in a virtual machine that cannot power
on.
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Procedure
1
Right-click a virtual machine in the inventory and select Edit Settings.
2
Click the VM Options tab and expand Advanced.
3
Click Edit Configuration.
4
(Optional) To add a parameter, click Add Row and type a name and value for the parameter.
5
(Optional) To change a parameter, type a new value in the Value text box for that parameter.
6
Click OK.
Enable or Disable the Locator LED on Storage Devices
Use the locator LED to identify specific storage devices, so that you can locate them among other devices.
You can turn the locator LED on or off.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
From the list of storage devices, select one or more disks and enable or disable the locator LED
indicator.
Option
Description
Enable
Click the Turns on the locator LED icon.
Disable
Click the Turns off the locator LED icon.
Erase Storage Devices
Certain functionalities, such as Virtual SAN or virtual flash resource require that you use clean devices. You
can erase an HHD or flash device and remove all preexisitng data.
Prerequisites
n
Make sure that the host is in connected state.
n
Verify that the devices you plan to erase are not in use.
n
Required privilege: Host.Config.Storage
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
Select one or more devices and click All Actions > Erase Partitions.
If you are erasing a single device, a dialog box with partition information opens.
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5
For a single device, verify that the partition information you are erasing is not critical.
6
Click OK to confirm your change.
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Working with Flash Devices
14
In addition to the regular storage hard disk drives (HDDs), ESXi supports flash storage devices.
Unlike the regular HDDs that are electromechanical devices containing moving parts, the flash devices use
semiconductors as their storage medium and have no moving parts. Typically, the flash devices are resilient
and provide faster access to data.
To detect flash devices, ESXi uses an inquiry mechanism based on T10 standards. The ESXi host can detect
flash devices on several storage arrays. Check with your vendor whether your storage array supports the
ESXi mechanism of flash device detection.
After the host detects the flash devices, you can use them for several tasks and functionalities.
This chapter includes the following topics:
n
“Using Flash Devices with ESXi,” on page 130
n
“Marking Storage Devices,” on page 130
n
“Monitor Flash Devices,” on page 132
n
“Best Practices for Flash Devices,” on page 132
n
“About Virtual Flash Resource,” on page 133
n
“Configuring Host Swap Cache,” on page 135
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Using Flash Devices with ESXi
In your ESXi environment, you can use flash devices with several functionalities.
Table 14‑1. Using Flash Devices with ESXi
Functionality
Description
Virtual SAN
Virtual SAN requires flash devices. For more information, see the Administering
VMware Virtual SAN documentation.
VMFS Datastores
You can create VMFS datastores on flash devices. Use the datastores for the
following purposes:
n Store virtual machines. Certain guest operating systems can identify virtual
disks stored on these datastores as flash virtual disks. See “Identifying Flash
Virtual Disks,” on page 130.
n Allocate datastore space for the ESXi host swap cache. See “Configuring Host
Swap Cache,” on page 135
Virtual Flash Resource (VFFS)
Set up a virtual flash resource and use it for the following functionalities:
Use as Virtual Flash Read Cache for your virtual machines. See Chapter 15,
“About VMware vSphere Flash Read Cache,” on page 137.
n Allocate the virtual flash resource for the ESXi host swap cache. This method is
an alternative way of host cache configuration that uses VFFS volumes instead
of VMFS datastores. See “Configure Host Swap Cache with Virtual Flash
Resource,” on page 136.
n If required by your vendor, use the virtual flash resource for I/O caching filters.
See Chapter 22, “Filtering Virtual Machine I/O,” on page 265.
n
Identifying Flash Virtual Disks
Guest operating systems can identify virtual disks that reside on flash-based datastores as flash virtual
disks.
To verify if this feature is enabled, guest operating systems can use standard inquiry commands such as
SCSI VPD Page (B1h) for SCSI devices and ATA IDENTIFY DEVICE (Word 217) for IDE devices.
For linked clones, native snapshots, and delta-disks, the inquiry commands report the virtual flash status of
the base disk.
Operating systems can detect that a virtual disk is a flash disk under the following conditions:
n
Detection of flash virtual disks is supported on ESXi 5.x and later hosts and virtual hardware version 8
or later.
n
Detection of flash virtual disks is supported only on VMFS5 or later.
n
If virtual disks are located on shared VMFS datastores with flash device extents, the device must be
marked as flash on all hosts.
n
For a virtual disk to be identified as virtual flash, all underlying physical extents should be flashbacked.
Marking Storage Devices
You can use the vSphere Web Client to mark storage devices that are not automatically recognized as local
flash devices.
When you configure Virtual SAN or set up a virtual flash resource, your storage environment must include
local flash devices.
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However, ESXi might not recognize certain storage devices as flash devices when their vendors do not
support automatic flash device detection. In other cases, certain devices might not be detected as local, and
ESXi marks them as remote. When devices are not recognized as local flash, they are excluded from the list
of devices offered for Virtual SAN or virtual flash resource. Marking these devices as local flash makes them
available for virtual SAN and virtual flash resource.
Mark Storage Devices as Flash
If ESXi does not recognize its devices as flash, mark them as flash devices.
ESXi does not recognize certain devices as flash when their vendors do not support automatic flash disk
detection. The Drive Type column for the devices shows HDD as their type.
Caution Marking the HDD devices as flash might deteriorate the performance of datastores and services
that use them. Mark the devices only if you are certain that they are flash devices.
Prerequisites
Verify that the device is not in use.
Procedure
1
Browse to the host in the vSphere Web Client object navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
From the list of storage devices, select one or several HDD devices to mark as flash devices and click the
Mark as Flash Disks ( ) icon.
5
Click Yes to save your changes.
The type of the devices changes to flash.
What to do next
If the flash device that you mark is shared among multiple hosts, make sure that you mark the device from
all hosts that share the device.
Mark Storage Devices as Local
ESXi enables you to mark devices as local. This action is useful in cases when ESXi is unable to determine
whether certain devices are local.
Prerequisites
n
Make sure that the device is not shared.
n
Power off virtual machines that reside on the device and unmount an associated datastore.
Procedure
1
Browse to the host in the vSphere Web Client object navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
From the list of storage devices, select one or several remote devices to mark as local and click the All
Actions icon.
5
Click Mark as Local, and click Yes to save your changes.
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Monitor Flash Devices
You can monitor certain critical flash device parameters, including Media Wearout Indicator, Temperature,
and Reallocated Sector Count, from an ESXi host.
Use the esxcli command to monitor flash devices.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
Run the following command to display the flash device statistics:
esxcli server=server_name storage core device smart get -d=flash device_ID
Best Practices for Flash Devices
Follow these best practices when you use flash devices in vSphere environment.
n
Make sure to use the latest firmware with flash devices. Frequently check with your storage vendors for
any updates.
n
Carefully monitor how intensively you use the flash device and calculate its estimated lifetime. The
lifetime expectancy depends on how actively you continue to use the flash device.
Estimate Lifetime of Flash Devices
When working with flash devices, monitor how actively you use them and calculate their estimated lifetime.
Typically, storage vendors provide reliable lifetime estimates for a flash device under ideal conditions. For
example, a vendor might guarantee a lifetime of 5 years under the condition of 20 GB writes per day.
However, the more realistic life expectancy of the device depends on how many writes per day your ESXi
host actually generates. Follow these steps to calculate the lifetime of the flash device.
Prerequisites
Note the number of days passed since the last reboot of your ESXi host. For example, ten days.
Procedure
1
Obtain the total number of blocks written to the flash device since the last reboot.
Run the esxcli storage core device stats get -d=device_ID command. For example:
~ # esxcli storage core device stats get -d t10.xxxxxxxxxxxxxxx
Device: t10.xxxxxxxxxxxxxxx
Successful Commands: xxxxxxx
Blocks Read: xxxxxxxx
Blocks Written: 629145600
Read Operations: xxxxxxxx
The Blocks Written item in the output shows the number of blocks written to the device since the last
reboot. In this example, the value is 629,145,600. After each reboot, it resets to 0.
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2
Calculate the total number of writes and convert to GB.
One block is 512 bytes. To calculate the total number of writes, multiply the Blocks Written value by 512,
and convert the resulting value to GB.
In this example, the total number of writes since the last reboot is approximately 322 GB.
3
Estimate the average number of writes per day in GB.
Divide the total number of writes by the number of days since the last reboot.
If the last reboot was ten days ago, you get 32 GB of writes per day. You can average this number over
the time period.
4
Estimate lifetime of your device by using the following formula:
vendor provided number of writes per day times vendor provided life span divided by actual average number of
writes per day
For example, if your vendor guarantees a lifetime of 5 years under the condition of 20 GB writes per
day, and the actual number of writes per day is 30 GB, the life span of your flash device will be
approximately 3.3 years.
About Virtual Flash Resource
You can aggregate local flash devices on an ESXi host into a single virtualized caching layer called virtual
flash resource.
When you set up the virtual flash resource, you create a new file system, Virtual Flash File System (VFFS).
VFFS is a derivative of VMFS, which is optimized for flash devices and is used to group the physical flash
devices into a single caching resource pool. As a non-persistent resource, it cannot be used to store virtual
machines.
The following vSphere functionalities require the virtual flash resource:
n
Virtual machine read cache. See Chapter 15, “About VMware vSphere Flash Read Cache,” on page 137.
n
Host swap cache. See “Configure Host Swap Cache with Virtual Flash Resource,” on page 136.
n
I/O caching filters, if required by your vendors. See Chapter 22, “Filtering Virtual Machine I/O,” on
page 265.
Before setting up the virtual flash resource, make sure that you use devices approved by the VMware
Compatibility Guide.
Considerations for Virtual Flash Resource
When you configure a virtual flash resource that is consumed by ESXi hosts and virtual machines, several
considerations apply.
n
You can have only one virtual flash resource, also called a VFFS volume, on a single ESXi host. The
virtual flash resource is managed only at the host's level.
n
You cannot use the virtual flash resource to store virtual machines. Virtual flash resource is a caching
layer only.
n
You can use only local flash devices for the virtual flash resource.
n
You can create the virtual flash resource from mixed flash devices. All device types are treated the same
and no distinction is made between SAS, SATA, or PCI express connectivity. When creating the resource
from mixed flash devices, make sure to group similar performing devices together to maximize
performance.
n
You cannot use the same flash devices for the virtual flash resource and Virtual SAN. Each requires its
own exclusive and dedicated flash device.
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n
After you set up a virtual flash resource, the total available capacity can be used and consumed by both
ESXi hosts as host swap cache and virtual machines as read cache.
n
You cannot choose individual flash devices to be used for either swap cache or read cache. All flash
devices are combined into a single flash resource entity.
Set Up Virtual Flash Resource
You can set up a virtual flash resource or add capacity to existing virtual flash resource.
To set up a virtual flash resource, you use local flash devices connected to your host. To increase the capacity
of your virtual flash resource, you can add more devices, up to the maximum number indicated in the
Configuration Maximums documentation. An individual flash device must be exclusively allocated to the
virtual flash resource and cannot be shared with any other vSphere service, such as Virtual SAN or VMFS.
Procedure
1
In the vSphere Web Client, navigate to the host.
2
Click the Configure tab.
3
Under Virtual Flash, select Virtual Flash Resource Management and click Add Capacity.
4
From the list of available flash devices, select one or more devices to use for the virtual flash resource
and click OK.
Under certain circumstances, you might not be able to see flash devices on the list. For more
information, see the Troubleshooting Flash Devices section in the vSphere Troubleshooting
documentation.
The virtual flash resource is created. The Device Backing area lists all devices that you use for the virtual
flash resource.
What to do next
You can use the virtual flash resource for cache configuration on the host and Flash Read Cache
configuration on virtual disks. In addition, I/O caching filters developed through vSphere APIs for I/O
Filtering might require the virtual flash resource.
You can increase the capacity by adding more flash devices to the virtual flash resource.
Remove Virtual Flash Resource
You might need to remove a virtual flash resource deployed on local flash devices to free the devices for
other services.
You cannot remove a virtual flash resource if it is configured with host swap cache or if the host has virtual
machines configured with Flash Read Cache that are powered on.
Procedure
1
In the vSphere Web Client, navigate to the host that has virtual flash configured.
2
Click the Configure tab.
3
Under Virtual Flash, select Virtual Flash Resource Management and click Remove All.
After you remove the virtual flash resource and erase the flash device, the device is available for other
operations.
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Virtual Flash Advanced Settings
You can change advanced options for virtual flash.
Procedure
1
In the vSphere Web Client, navigate to the host.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
Select the setting to change and click the Edit button.
5
Option
Description
VFLASH.VFlashResourceUsageThr
eshold
The system triggers the Host vFlash resource usage alarm when a
virtual flash resource usage exceeds the threshold. The default threshold is
80%. You can change the threshold to an appropriate value. The alarm is
automatically cleared when the virtual flash resource usage drops below
the threshold.
VFLASH.MaxResourceGBForVmCa
che
An ESXi host stores Flash Read Cache metadata in RAM. The default limit
of total virtual machine cache size on the host is 2TB. You can reconfigure
this setting. You must restart the host for the new setting to take effect.
Click OK.
Configuring Host Swap Cache
Your ESXi hosts can use a portion of a flash-backed storage entity as a swap cache shared by all virtual
machines.
The host-level cache is made up of files on a low-latency disk that ESXi uses as a write back cache for virtual
machine swap files. The cache is shared by all virtual machines running on the host. Host-level swapping of
virtual machine pages makes the best use of potentially limited flash device space.
Depending on your environment and licensing package, the following methods of configuring the host-level
swap cache are available. Both methods provide similar results.
n
You can create a VMFS datastore on a flash device, and then use the datastore to allocate space for host
cache. The host reserves a certain amount of space for swapping to host cache.
n
If you have an appropriate vSphere license that allows you to set up and manage a virtual flash
resource, you can use the resource to configure swap cache on the host. The host swap cache is allocated
from a portion of the virtual flash resource.
Configure Host Cache with VMFS Datastore
Enable your ESXi host to swap to the host cache. You can also change the percentage of space allocated for
the host cache.
Use this task if you do not have an appropriate license that allows you to set up and manage a virtual flash
resource. If you have the license, use the virtual flash resource for host cache configuration.
Prerequisites
Create a flash-backed VMFS datastore. See “Create a VMFS Datastore,” on page 160.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
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3
Under Storage, click Host Cache Configuration.
4
Select the flash datastore in the list and click the Allocate space for host cache icon.
5
To enable the host swap cache on a per-datastore basis, select the Allocate space for host cache check
box.
By default, maximum available space is allocated for the host cache.
6
(Optional) To change the host cache size, select Custom size and make appropriate adjustments.
7
Click OK.
Configure Host Swap Cache with Virtual Flash Resource
You can reserve a certain amount of virtual flash resource for host swap cache.
Prerequisites
Set up a virtual flash resource. “Set Up Virtual Flash Resource,” on page 134.
Note If an ESXi host configured with virtual flash is in maintenance mode, you cannot add or modify a
host swap cache. You must first exit maintenance mode on the host before you configure a host swap cache.
Procedure
136
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Virtual Flash, select Virtual Flash Host Swap Cache Configuration and click Edit.
4
Select the Enable virtual flash host swap cache check box.
5
Specify the amount of virtual flash resource to reserve for host swap cache.
6
Click OK.
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About VMware vSphere Flash Read
Cache
15
Flash Read Cache™ lets you accelerate virtual machine performance through the use of host resident flash
devices as a cache.
You can reserve a Flash Read Cache for any individual virtual disk. The Flash Read Cache is created only
when a virtual machine is powered on, and it is discarded when a virtual machine is suspended or powered
off. When you migrate a virtual machine you have the option to migrate the cache. By default the cache is
migrated if the virtual flash module on the source and destination hosts are compatible. If you do not
migrate the cache, the cache is rewarmed on the destination host. You can change the size of the cache while
a virtual machine is powered on. In this instance, the existing cache is discarded and a new write-through
cache is created, which results in a cache warm up period. The advantage of creating a new cache is that the
cache size can better match the application's active data.
Flash Read Cache supports write-through or read caching. Write-back or write caching are not supported.
Data reads are satisfied from the cache, if present. Data writes are dispatched to the backing storage, such as
a SAN or NAS. All data that is read from or written to the backing storage is unconditionally stored in the
cache.
Flash Read Cache does not support RDMs in physical compatibility. Virtual compatibility RDMs are
supported with Flash Read Cache.
Watch the video for more information about Flash Read Cache.
Configuring vSphere Flash Read Cache
(http://link.brightcove.com/services/player/bcpid2296383276001?
bctid=ref:video_config_vsphere_flash_read_cache)
Note Not all workloads benefit with a Flash Read Cache. The performance boost depends on your
workload pattern and working set size. Read-intensive workloads with working sets that fit into the cache
can benefit from a Flash Read Cache configuration. By configuring Flash Read Cache for your read-intensive
workloads additional I/O resources become available on your shared storage, which can result in a
performance increase for other workloads even though they are not configured to use Flash Read Cache.
This chapter includes the following topics:
n
“DRS Support for Flash Read Cache,” on page 138
n
“vSphere High Availability Support for Flash Read Cache,” on page 138
n
“Configure Flash Read Cache for a Virtual Machine,” on page 138
n
“Migrate Virtual Machines with Flash Read Cache,” on page 139
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DRS Support for Flash Read Cache
DRS supports virtual flash as a resource.
DRS manages virtual machines with Flash Read Cache reservations. Every time DRS runs, it displays the
available virtual flash capacity reported by the ESXi host. Each host supports one virtual flash resource. DRS
selects a host that has sufficient available virtual flash capacity to start a virtual machine. DRS treats
powered-on virtual machines with a Flash Read Cache as soft affined to their current host and moves them
only for mandatory reasons or if necessary to correct host over-utilization.
vSphere High Availability Support for Flash Read Cache
Flash Read Cache is supported by High Availability (HA).
When vSphere HA restarts a virtual machine configured with Flash Read Cache, the virtual machine is
restarted on a host in the cluster where the Flash Read Cache, CPU, Memory and overhead reservations are
met. vSphere HA will not restart a virtual machine if unreserved flash is insufficient to meet the virtual flash
reservation. You must manually reconfigure a virtual machine to reduce or drop the Flash Read Cache, if the
target host does not have sufficient virtual flash resource available.
Configure Flash Read Cache for a Virtual Machine
You can configure Flash Read Cache for your virtual machine.
Enabling Flash Read Cache lets you specify block size and cache size reservation.
Block size is the minimum number of contiguous bytes that can be stored in the cache. This block size can be
larger than the nominal disk block size of 512 bytes, between 4 KB and 1024 KB. If a guest operating system
writes a single 512 byte disk block, the surrounding cache block size bytes will be cached. Do not confuse
cache block size with disk block size.
Reservation is a reservation size for cache blocks. There is a minimum number of 256 cache blocks. If the
cache block size is 1 MB, then the minimum cache size is 256 MB. If the cache block size is 4 K, then the
minimum cache size is 1 MB.
For more information about sizing guidelines, search for the Performance of vSphere Flash Read Cache in
VMware vSphere white paper on the VMware web site.
Prerequisites
Set up virtual flash resource.
Procedure
1
Navigate to the virtual machine.
2
Right-click the virtual machine and select Edit Settings.
3
On the Virtual Hardware tab, expand Hard disk to view the disk options.
4
To enable Flash Read Cache for the virtual machine, enter a value in the Virtual Flash Read Cache text
box.
5
Click Advanced to specify the following parameters.
6
138
Option
Description
Reservation
Select a cache size reservation.
Block Size
Select a block size.
Click OK.
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Chapter 15 About VMware vSphere Flash Read Cache
Migrate Virtual Machines with Flash Read Cache
When you migrate a powered on virtual machine from one host to another, you can specify whether or not
to migrate Flash Read Cache contents with the virtual disks.
Prerequisites
If you plan to migrate Flash Read Cache contents, configure a sufficient virtual flash resource on the
destination host.
Procedure
1
Right-click the running virtual machine and select Migrate.
2
Specify the migration type.
Option
Description
Change compute resource only
Migrate the virtual machines to another host or cluster.
Change both compute resource and
storage
Migrate the virtual machines to a specific host or cluster and their storage
to a specific datastore or datastore cluster.
3
Select the destination host and click Next.
4
Specify a migration setting for all virtual disks configured with virtual Flash Read Cache. This
migration parameter does not appear when you do not change the host, but only change the datastore.
Flash Read Cache Migration
Settings
5
6
Description
Always migrate the cache contents
Virtual machine migration proceeds only if all of the cache contents can be
migrated to the destination host. This option is useful when the cache is
small or the cache size closely matches the application's active data.
Do not migrate the cache contents
Deletes the write-through cache. Cache is recreated on the destination host.
This option is useful when the cache size is large or the cache size is larger
than the application's active data.
If you have multiple virtual disks with Flash Read Cache, you can adjust the migration setting for each
individual disk.
a
Click Advanced.
b
Select a virtual disk for which you want to modify the migration setting.
c
From the drop-down menu in the Virtual Flash Read Cache Migration Setting column, select an
appropriate option.
Complete your migration configuration and click Finish.
What to do next
Verify the successful migration by looking at the Summary tab of the virtual machine:
n
Make sure that the tab displays the correct IP address of the destination host.
n
Make sure that the VM Hardware panel displays correct Virtual Flash Read Cache information for each
virtual disk.
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16
Working with Datastores
Datastores are logical containers, analogous to file systems, that hide specifics of physical storage and
provide a uniform model for storing virtual machine files. Datastores can also be used for storing ISO
images, virtual machine templates, and floppy images.
Depending on the storage you use, the datastores can be of different types.
Table 16‑1. Types of Datastores
Datastore Type
Description
VMFS (version 3, 5, and 6)
Datastores that you deploy on block storage devices use
the vSphere Virtual Machine File System format, a special
high-performance file system format that is optimized for
storing virtual machines. See “Understanding VMFS
Datastores,” on page 142.
NFS (version 3 and 4.1)
An NFS client built into ESXi uses the Network File System
(NFS) protocol over TCP/IP to access a designated NFS
volume that is located on a NAS server. The ESXi host
mounts the volume as an NFS datastore, and uses it for
storage needs. ESXi supports versions 3 and 4.1 of the NFS
protocol. See “Understanding Network File System
Datastores,” on page 150
Virtual SAN
Virtual SAN aggregates all local capacity devices available
on the hosts into a single datastore shared by all hosts in
the Virtual SAN cluster. See the Administering VMware
Virtual SAN documentation.
Virtual Volumes
Virtual Volumes datastore represents a storage container in
vCenter Server and vSphere Web Client. See Chapter 21,
“Working with Virtual Volumes,” on page 239.
After creating the datastores, you can perform several administrative operations on the datastores. Certain
operations, such as renaming a datastore, are available for all types of datastores. While others apply to
specific types of datastores.
You can also organize the datastores in different ways. For example, you can group them into folders
according to business practices. After you group the datastores, you can assign the same permissions and
alarms on the datastores in the group at one time.
You can add the datastores to datastore clusters. A datastore cluster is a collection of datastores with shared
resources and a shared management interface. When you create the datastore cluster, you can use Storage
DRS to manage storage resources. For information about datastore clusters, see the vSphere Resource
Management documentation.
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This chapter includes the following topics:
n
“Understanding VMFS Datastores,” on page 142
n
“Understanding Network File System Datastores,” on page 150
n
“Creating Datastores,” on page 160
n
“Managing Duplicate VMFS Datastores,” on page 163
n
“Increasing VMFS Datastore Capacity,” on page 165
n
“Administrative Operations for Datastores,” on page 166
n
“Set Up Dynamic Disk Mirroring,” on page 173
n
“Collecting Diagnostic Information for ESXi Hosts on a Storage Device,” on page 174
n
“Checking Metadata Consistency with VOMA,” on page 177
n
“Configuring VMFS Pointer Block Cache,” on page 179
Understanding VMFS Datastores
To store virtual disks, ESXi uses datastores. The datastores are logical containers that hide specifics of
physical storage from virtual machines and provide a uniform model for storing the virtual machine files.
The datastores that you deploy on block storage devices use the native vSphere Virtual Machine File System
(VMFS) format. It is a special high-performance file system format that is optimized for storing virtual
machines.
Use the vSphere Web Client to set up the VMFS datastore in advance on the block-based storage device that
your ESXi host discovers. The VMFS datastore can be extended to span over several physical storage devices
that include SAN LUNs and local storage. This feature allows you to pool storage and gives you flexibility in
creating the datastore necessary for your virtual machines.
You can increase the capacity of the datastore while the virtual machines are running on the datastore. This
ability lets you add new space to your VMFS datastores as your virtual machine requires it. VMFS is
designed for concurrent access from multiple physical machines and enforces the appropriate access
controls on the virtual machine files.
Versions of VMFS Datastores
Several versions of the VMFS file system have been released since its introduction. ESXi supports VMFS3,
VMFS5, and VMFS6.
For all VMFS version, ESXi offers complete read and write support. On all versions of VMFS, you can create
and power on virtual machines.
Table 16‑2. Host Access to VMFS Versions
VMFS
ESXi
VMFS6
Read and write
VMFS5
Read and write
VMFS3
Read and write
Note You can continue to use existing VMFS3 datastores, but you cannot create
new ones. If you have existing VMFS3 datastores, migrate virtual machines to the
VMFS6 datastore.
The following table compares major characteristics of VMFS5 and VMFS6. For additional information, see
Configuration Maximums .
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Table 16‑3. Comparing VMFS5 and VMFS6
Features and Functionalities
VMFS5
VMFS6
Access for ESXi 6.5 hosts
Yes
Yes
Access for ESXi hosts version 6.0 and earlier
Yes
No
Datastores per host
512
512
512n storage devices
Yes (default)
Yes
512e storage devices
Yes. Not supported on local
512e devices.
Yes (default)
Automatic space reclamation
No
Yes
Manual space reclamation through the esxcli command.
See “Manually Reclaim Accumulated Storage Space,” on
page 296.
Yes
Yes
Space reclamation from guest OS
Limited
Yes
GPT storage device partitioning
Yes
Yes
MBR storage device partitioning
Yes
For a VMFS5 datastore that
has been previously
upgraded from VMFS3.
No
Storage devices greater than 2 TB for each VMFS extent
Yes
Yes
Support for virtual machines with large capacity virtual
disks, or disks greater than 2 TB
Yes
Yes
Support of small files of 1 KB
Yes
Yes
Default use of ATS-only locking mechanisms on storage
devices that support ATS. See “VMFS Locking
Mechanisms,” on page 146.
Yes
Yes
Block size
Standard 1 MB
Standard 1 MB
Default snapshots
VMFSsparse for virtual
disks smaller than 2 TB.
SEsparse for virtual disks
larger than 2 TB.
SEsparse
Virtual disk emulation type
512n
512n
vMotion
Yes
Yes
Storage vMotion across different datastore types
Yes
Yes
High Availability and Fault Tolerance
Yes
Yes
DRS and Storage DRS
Yes
Yes
RDM
Yes
Yes
When you work with VMFS5 and VMFS6 datastores, consider the following:
n
Upgrade. After you upgrade your ESXi hosts to version 6.5, you can continue using any existing VMFS5
datastores. To take advantage of VMFS6 features, create a VMFS6 datastore and migrate virtual
machines from the VMFS5 datastore to VMFS6 datastore. You cannot upgrade the VMFS5 datastore to
VMFS6.
n
Datastore Extents. A spanned VMFS datastore must use only homogeneous storage devices, either 512n
or 512e. The spanned datastore cannot extend over devices of different formats.
n
Block Size. The block size on a VMFS datastore defines the maximum file size and the amount of space
a file occupies. VMFS5 and VMFS6 datastores support the block size of 1 MB.
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n
Storage vMotion. Storage vMotion supports migration across VMFS, Virtual SAN, and Virtual Volumes
datastores. vCenter Server performs compatibility checks to validate Storage vMotion across different
types of datastores.
n
Storage DRS. VMFS5 and VMFS6 can coexist in the same datastore cluster. However, all datastores in
the cluster must use homogeneous storage devices, either 512n or 512e. Do not mix devices of different
formats within the same datastore cluster.
Storage Device Formats and VMFS Datastores
You can deploy VMFS datastores on 512n and 512e storage devices. When you set up a new VMFS
datastore, GPT is used to format the device. In specific cases, VMFS can support the MBR format.
Device Sector Formats and VMFS Versions
ESXi supports storage devices with traditional and advanced sector formats.
In storage, a sector is a subdivision of a track on a storage disk or device. Each sector stores a fixed amount
of data. Traditional 512n storage devices have been using a native 512-bytes sector size. In addition, due to
the increasing demand for larger capacities, the storage industry has introduced advanced formats, such as
512-byte emulation, or 512e. 512e is the advanced format in which the physical sector size is 4,096 bytes, but
the logical sector size emulates 512-bytes sector size. Storage devices that use the 512e format can support
legacy applications and guest operating systems.
When you set up a datastore on a 512e storage device, VMFS6 is selected by default. For 512n storage
devices, the default option is VMFS5, but you can select VMFS6.
This table compares native 512-byte storage devices to the devices with the advanced 512e format.
Storage Device
Format
Logical Sector Size
Physical Sector Size
VMFS Datastore
512n
512
512
VMFS5 (default) and VMFS6
512e
512
4,096
VMFS6 (default) and VMFS5
Note Local 512e storage devices
do not support VMFS5.
Device Partition Formats and VMFS Version
Any new VMFS5 or VMFS6 datastore uses GUID partition table (GPT) to format the storage device. The
GPT format enables you to create datastores larger than 2 TB. If your VMFS5 datastore has been previously
upgraded from VMFS3, it continues to use the master boot record (MBR) partition format, which is
characteristic for VMFS3. Conversion to GPT happens only after you expand the datastore to a size larger
than 2 TB.
VMFS Datastores as Repositories
ESXi can format SCSI-based storage devices as VMFS datastores. VMFS datastores primarily serve as
repositories for virtual machines.
Note Always have only one VMFS datastore for each LUN.
You can store multiple virtual machines on the same VMFS datastore. Each virtual machine, encapsulated in
a set of files, occupies a separate single directory. For the operating system inside the virtual machine, VMFS
preserves the internal file system semantics, which ensures correct application behavior and data integrity
for applications running in virtual machines.
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When you run multiple virtual machines, VMFS provides specific locking mechanisms for the virtual
machine files. As a result, the virtual machines can operate safely in a SAN environment where multiple
ESXi hosts share the same VMFS datastore.
In addition to the virtual machines, the VMFS datastores can store other files, such as the virtual machine
templates and ISO images.
Sharing a VMFS Datastore Across Hosts
As a cluster file system, VMFS lets multiple ESXi hosts access the same VMFS datastore concurrently.
Figure 16‑1. Sharing a VMFS Datastore Across Hosts
host
A
host
B
host
C
VM1
VM2
VM3
VMFS volume
disk1
disk2
virtual
disk
files
disk3
For information on the maximum number of hosts that can connect to a single VMFS datastore, see the
Configuration Maximums document.
To ensure that multiple hosts do not access the same virtual machine at the same time, VMFS provides ondisk locking.
Sharing the VMFS volume across multiple hosts offers several advantages, for example, the following:
n
You can use VMware Distributed Resource Scheduling (DRS) and VMware High Availability (HA).
You can distribute virtual machines across different physical servers. That means you run a mix of
virtual machines on each server, so that not all experience high demand in the same area at the same
time. If a server fails, you can restart virtual machines on another physical server. If the failure occurs,
the on-disk lock for each virtual machine is released. For more information about VMware DRS, see the
vSphere Resource Management documentation. For information about VMware HA, see the vSphere
Availability documentation.
n
You can use vMotion to migrate running virtual machines from one physical server to another. For
information about migrating virtual machines, see the vCenter Server and Host Management
documentation.
To create a shared datastore, mount the datastore on those ESXi hosts that require the datastore access.
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VMFS Metadata Updates
A VMFS datastore holds virtual machine files, directories, symbolic links, RDM descriptor files, and so on.
The datastore also maintains a consistent view of all the mapping information for these objects. This
mapping information is called metadata.
Metadata is updated each time you perform datastore or virtual machine management operations. Examples
of operations requiring metadata updates include the following:
n
Creating, growing, or locking a virtual machine file
n
Changing attributes of a file
n
Powering a virtual machine on or off
n
Creating or deleting a VMFS datastore
n
Expanding a VMFS datastore
n
Creating a template
n
Deploying a virtual machine from a template
n
Migrating a virtual machine with vMotion
When metadata changes are made in a shared storage environment, VMFS uses special locking mechanisms
to protect its data and prevent multiple hosts from concurrently writing to the metadata.
VMFS Locking Mechanisms
In a shared storage environment, when multiple hosts access the same VMFS datastore, specific locking
mechanisms are used. These locking mechanisms prevent multiple hosts from concurrently writing to the
metadata and ensure that no data corruption occurs.
Depending on its configuration and the type of underlying storage, a VMFS datastore can use different
types of locking mechanisms. It can exclusively use the atomic test and set locking mechanism (ATS-only),
or use a combination of ATS and SCSI reservations (ATS+SCSI).
ATS-Only Mechanism
For storage devices that support T10 standard-based VAAI specifications, VMFS provides ATS locking, also
called hardware assisted locking. The ATS algorithm supports discrete locking per disk sector. All newly
formatted VMFS5 and VMFS6 datastores use the ATS-only mechanism if the underlying storage supports it,
and never use SCSI reservations.
When you create a multi-extent datastore where ATS is used, vCenter Server filters out non-ATS devices.
This filtering allows you to use only those devices that support the ATS primitive.
In certain cases, you might need to turn off the ATS-only setting for a VMFS5 or VMFS6 datastore. For
information, see “Change Locking Mechanism to ATS+SCSI,” on page 149.
ATS+SCSI Mechanism
A VMFS datastore that supports the ATS+SCSI mechanism is configured to use ATS and attempts to use it
when possible. If ATS fails, the VMFS datastore reverts to SCSI reservations. In contrast with the ATS
locking, the SCSI reservations lock an entire storage device while an operation that requires metadata
protection is performed. After the operation completes, VMFS releases the reservation and other operations
can continue.
Datastores that use the ATS+SCSI mechanism include VMFS5 datastores that were upgraded from VMFS3.
In addition, new VMFS5 or VMFS6 datastores on storage devices that do not support ATS use the ATS+SCSI
mechanism.
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If your VMFS datastore reverts to SCSI reservations, you might notice performance degradation caused by
excessive SCSI reservations. For information about how to reduce SCSI reservations, see the vSphere
Troubleshooting documentation.
Display VMFS Locking Information
Use the esxcli command to obtain information about the locking mechanism that a VMFS datastore uses.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To display information related to VMFS locking mechanisms, run the following command:
esxcli --server=server_name storage vmfs lockmode list
The table lists items that the output of the command might include.
Table 16‑4. VMFS Locking Information
Fields
Values
Locking Modes
Descriptions
Indicates the locking configuration of
the datastore.
ATS-only
The datastore is configured to use ATSonly.
ATS+SCSI
The datastore is configured to use ATS.
If ATS fails or is not supported, the
datastore can revert to SCSI.
ATS upgrade pending
The datastore is in the process of an
online upgrade to ATS-only.
ATS downgrade pending
The datastore is in the process of an
online downgrade to ATS+SCSI.
ATS Compatible
Indicates whether the datastore can be
configured for ATS-only or not.
ATS Upgrade Modes
Indicates the type of upgrade that the
datastore supports.
ATS Incompatibility Reason
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None
The datastore is not ATS-only
compatible.
Online
The datastore can be used during its
upgrade to ATS-only.
Offline
The datastore cannot be used during
its upgrade to ATS-only.
If the datastore is not compatible with
ATS-only, the item indicates the reason
for the incompatibility.
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Change VMFS Locking to ATS-Only
If your VMFS datastore uses the ATS+SCSI locking mechanism, you can change to ATS-only locking.
Typically, VMFS5 datastores that were previously upgraded from VMFS3 continue using the ATS+SCSI
locking mechanism. If the datastores are deployed on ATS-enabled hardware, they are generally eligible for
an upgrade to ATS-only locking. Depending on your vSphere environment, you can use one of the following
upgrade modes:
n
The online upgrade to ATS-only is available for most single-extent VMFS5 datastores. While you
perform the online upgrade on one of the hosts, other hosts can continue using the datastore.
n
The offline upgrade to ATS-only must be used for VMFS5 datastores that span multiple physical
extents. Datastores composed of multiple extents are not eligible for the online upgrade. These
datastores require that no hosts actively use the datastores at the time of the upgrade request.
Procedure
1
Prepare for an Upgrade to ATS-Only on page 148
You must perform several steps to prepare your environment for an online or offline upgrade to ATSonly locking.
2
Upgrade Locking Mechanism to ATS-Only on page 148
If a VMFS datastore is ATS-only compatible, you can upgrade its locking mechanism from ATS+SCSI
to ATS-only.
Prepare for an Upgrade to ATS-Only
You must perform several steps to prepare your environment for an online or offline upgrade to ATS-only
locking.
Procedure
1
Upgrade all hosts that access the VMFS5 datastore to the newest version of vSphere.
2
Determine whether the datastore is eligible for an upgrade of its current locking mechanism by running
the esxcli storage vmfs lockmode list command.
The following sample output fields indicate that the datastore is eligible for an upgrade, and show its
current locking mechanism and an upgrade mode available for the datastore.
Locking Mode
-----------ATS+SCSI
3
ATS Compatible
-------------true
ATS Upgrade Modes
----------------Online or Offline
Depending on the upgrade mode available for the datastore, perform one of the following actions:
Upgrade Mode
Action
Online
Verify that all hosts have consistent storage connectivity to the VMFS
datastore.
Offline
Verify that no hosts are actively using the datastore.
Upgrade Locking Mechanism to ATS-Only
If a VMFS datastore is ATS-only compatible, you can upgrade its locking mechanism from ATS+SCSI to
ATS-only.
Most datastores that do not span multiple extents are eligible for an online upgrade. While you perform the
online upgrade on one of the ESXi hosts, other hosts can continue using the datastore. The online upgrade
completes only after all hosts have closed the datastore.
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Prerequisites
If you plan to complete the upgrade of the locking mechanism by putting the datastore into maintenance
mode, disable Storage DRS. This prerequisite applies only to an online upgrade.
Procedure
1
Perform an upgrade of the locking mechanism by running the following command:
esxcli storage vmfs lockmode set -a|--ats -l|--volume-label= VMFS label -u|--volume-uuid=
VMFS UUID.
2
For an online upgrade, perform additional steps.
a
Close the datastore on all hosts that have access to the datastore, so that the hosts can recognize the
change.
You can use one of the following methods:
b
n
Unmount and mount the datastore.
n
Put the datastore into maintenance mode and exit maintenance mode.
Verify that the Locking Mode status for the datastore changed to ATS-only by running:
esxcli storage vmfs lockmode list
c
If the Locking Mode displays any other status, for example ATS UPGRADE PENDING, check
which host has not yet processed the upgrade by running:
esxcli storage vmfs host list
Change Locking Mechanism to ATS+SCSI
When you create a VMFS5 datastore on a device that supports atomic test and set (ATS) locking, the
datastore is set to use the ATS-only locking mechanism. In certain circumstances, you might need to
downgrade the ATS-only locking to ATS+SCSI.
You might need to switch to the ATS+SCSI locking mechanism when, for example, your storage device is
downgraded or firmware updates fail and the device no longer supports ATS.
The downgrade process is similar to the ATS-only upgrade. As with the upgrade, depending on your
storage configuration, you can perform the downgrade in online or offline mode.
Procedure
1
Change the locking mechanism to ATS+SCSI by running the following command:
esxcli storage vmfs lockmode set -s|--scsi -l|--volume-label= VMFS label -u|--volume-uuid=
VMFS UUID.
2
For an online mode, close the datastore on all hosts that have access to the datastore, so that the hosts
can recognise the change.
Snapshot Formats on VMFS
When you take a snapshot, the state of the virtual disk is preserved, which prevents the guest operating
system from writing to it. A delta or child disk is created. The delta disk represents the difference between
the current state of the virtual disk and the state that existed at the time that the previous snapshot was
taken. On the VMFS datastore, the delta disk is a sparse disk.
Sparse disks use the copy-on-write mechanism, in which the virtual disk contains no data, until the data is
copied there by a write operation. This optimization saves storage space.
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Depending on the type of your datastore, delta disks use different sparse formats.
VMFSsparse
VMFS5 uses the VMFSsparse format for virtual disks smaller than 2 TB.
VMFSsparse is implemented on top of VMFS, and I/Os issued to a snapshot
VM are processed by the VMFSsparse layer. Technically, VMFSsparse is a
redo-log that starts empty, immediately after a VM snapshot is taken. The
redo-log grows to the size of its base vmdk, when the entire vmdk is
rewritten with new data after the VM snapshotting. This redo-log is just a file
in the VMFS datastore. Upon snapshot creation, the base vmdk attached to
the VM is changed to the newly created sparse vmdk.
SEsparse
SEsparse is a default format for all delta disks on the VMFS6 datastores. On
VMFS5, SEsparse is used for virtual disks of the size 2 TB and larger.
SEsparse is a format similar to VMFSsparse with some enhancements. This
format is space efficient and supports space reclamation. With space
reclamation, blocks that are deleted by the guest OS are marked and
commands are issued to the SEsparse layer in the hypervisor to unmap those
blocks. This helps to reclaim space allocated by SEsparse once the guest
operating system has deleted that data. For more information about space
reclamation, see “Storage Space Reclamation,” on page 293.
Snapshot Migration
You can migrate VMs with snapshots across different datastores. The following considerations apply:
n
If you migrate a VM with the VMFSsparse snapshot to VMFS6, the snapshot format changes to
SEsparse.
n
When a VM with a vmdk of the size smaller than 2 TB is migrated to VMFS5, the snapshot format
changes to VMFSsparse.
n
You cannot mix VMFSsparse redo-logs with SEsparse redo-logs in the same hierarchy.
Understanding Network File System Datastores
An NFS client built into ESXi uses the Network File System (NFS) protocol over TCP/IP to access a
designated NFS volume that is located on a NAS server. The ESXi host can mount the volume and use it for
its storage needs. vSphere supports versions 3 and 4.1 of the NFS protocol.
Typically, the NFS volume or directory is created by a storage administrator and is exported from the NFS
server. You do not need to format the NFS volume with a local file system, such as VMFS. Instead, you
mount the volume directly on the ESXi hosts and use it to store and boot virtual machines in the same way
that you use the VMFS datastores.
In addition to storing virtual disks on NFS datastores, you can use NFS as a central repository for ISO
images, virtual machine templates, and so on. If you use the datastore for the ISO images, you can connect
the CD-ROM device of the virtual machine to an ISO file on the datastore. You then can install a guest
operating system from the ISO file.
NFS Protocols and ESXi
ESXi supports NFS protocols version 3 and 4.1. To support both versions, ESXi uses two different NFS
clients.
Comparing Versions of NFS Clients
The following table lists capabilities that the NFS version 3 and 4.1 support.
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Characteristics
NFS version 3
NFS version 4.1
Security mechanisms
AUTH_SYS
AUTH_SYS and Kerberos (krb5 and
krb5i)
Encryption algorithms with Kerberos
N/A
AES256-CTS-HMAC-SHA1-96 and
AES128-CTS-HMAC-SHA1-96
Multipathing
Not supported
Supported through the session
trunking
Locking mechanisms
Propriety client-side locking
Server-side locking
Hardware acceleration
Supported
Supported
Thick virtual disks
Supported
Supported
IPv6
Supported
Supported for AUTH_SYS and
Kerberos
ISO images presented as CD-ROMs to
virtual machines
Supported
Supported
Virtual machine snapshots
Supported
Supported
Virtual machines with virtual disks
greater than 2 TB
Supported
Supported
NFS Protocols and vSphere Solutions
The following table lists major vSphere solutions that NFS versions support.
vSphere Features
NFS version 3
NFS version 4.1
vMotion and Storage vMotion
Yes
Yes
High Availability (HA)
Yes
Yes
Fault Tolerance (FT)
Yes
Yes
Distributed Resource Scheduler (DRS)
Yes
Yes
Host Profiles
Yes
Yes
Storage DRS
Yes
No
Storage I/O Control
Yes
No
Site Recovery Manager
Yes
No
Virtual Volumes
Yes
Yes
vSphere Replication
Yes
Yes
vRealize Operations Manager
Yes
Yes
NFS 4.1 and Fault Tolerance
Virtual machines on NFS v4.1 support the new Fault Tolerance mechanism introduced in vSphere 6.0.
Virtual machines on NFS v4.1 do not support the old, legacy Fault Tolerance mechanism.
In vSphere 6.0, the newer Fault Tolerance mechanism can accommodate symmetric multiprocessor (SMP)
virtual machines with up to four vCPUs. Earlier versions of vSphere used a different technology for Fault
Tolerance, with different requirements and characteristics.
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NFS Upgrades
When you upgrade ESXi to version 6.5, existing NFS 4.1 datastores automatically begin supporting
functionalities that were not available in the previous ESXi release. These functionalities include Virtual
Volumes, hardware acceleration, and so on.
ESXi does not support automatic datastore conversions from NFS version 3 to NFS 4.1.
If you want to upgrade your NFS 3 datastore, the following options are available:
n
Create the NFS 4.1 datastore, and then use Storage vMotion to migrate virtual machines from the old
datastore to the new one.
n
Use conversion methods provided by your NFS storage server. For more information, contact your
storage vendor.
n
Unmount the NFS 3 datastore, and then mount as NFS 4.1 datastore.
Caution If you use this option, make sure to unmount the datastore from all hosts that have access to
the datastore. The datastore can never be mounted by using both protocols at the same time.
NFS Storage Guidelines and Requirements
When you use NFS storage, follow specific guidelines related to NFS server configuration, networking, NFS
datastores, and so on.
n
NFS Server Configuration on page 153
When you configure NFS servers to work with ESXi, follow recommendation of your storage vendor.
In addition to these general recommendations, use specific guidelines and best practices that apply to
NFS in vSphere environment.
n
NFS Networking on page 153
An ESXi host uses TCP/IP network connection to access a remote NAS server. Certain guidelines and
best practices exist for configuring the networking when you use NFS storage.
n
NFS File Locking on page 153
File locking mechanisms are used to restrict access to data stored on a server to only one user or
process at a time. NFS 3 and NFS 4.1 use incompatible file locking mechanisms.
n
NFS Security on page 154
With NFS 3 and NFS 4.1, ESXi supports the AUTH_SYS security. In addition, for NFS 4.1, the Kerberos
security mechanism is supported.
n
NFS Multipathing on page 154
While NFS 3 with ESXi does not provide multipathing support, NFS 4.1 supports multiple paths.
n
NFS and Hardware Acceleration on page 154
Virtual disks created on NFS datastores are thin-provisioned by default. To be able to create thickprovisioned virtual disks, you must use hardware acceleration that supports the Reserve Space
operation.
n
NFS Datastores on page 154
When you create an NFS datastore, make sure to follow specific guidelines.
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NFS Server Configuration
When you configure NFS servers to work with ESXi, follow recommendation of your storage vendor. In
addition to these general recommendations, use specific guidelines and best practices that apply to NFS in
vSphere environment.
The guidelines include the following items.
n
Make sure that the NAS servers you use are listed in the VMware HCL. Use the correct version for the
server firmware.
n
Ensure that the NFS volume is exported using NFS over TCP.
n
Make sure that the NAS server exports a particular share as either NFS 3 or NFS 4.1, but does not
provide both protocol versions for the same share. The NAS server must enforce this policy because
ESXi does not prevent mounting the same share through different NFS versions.
n
NFS 3 and non-Kerberos (AUTH_SYS) NFS 4.1 do not support the delegate user functionality that
enables access to NFS volumes using nonroot credentials. If you use NFS 3 or non-Kerberos NFS 4.1,
ensure that each host has root access to the volume. Different storage vendors have different methods of
enabling this functionality, but typically the NAS servers use the no_root_squash option. If the NAS
server does not grant root access, you can still mount the NFS datastore on the host. However, you
cannot create any virtual machines on the datastore.
n
If the underlying NFS volume, on which files are stored, is read-only, make sure that the volume is
exported as a read-only share by the NFS server. Or mount the volume as a read-only datastore on the
ESXi host. Otherwise, the host considers the datastore to be read-write and might not be able to open
the files.
NFS Networking
An ESXi host uses TCP/IP network connection to access a remote NAS server. Certain guidelines and best
practices exist for configuring the networking when you use NFS storage.
For more information, see the vSphere Networking documentation.
n
For network connectivity, use a standard network adapter in your ESXi host.
n
ESXi supports Layer 2 and Layer 3 Network switches. If you use Layer 3 switches, ESXi hosts and NFS
storage arrays must be on different subnets and the network switch must handle the routing
information.
n
Configure a VMkernel port group for NFS storage. You can create the VMkernel port group for IP
storage on an existing virtual switch (vSwitch) or on a new vSwitch. The vSwitch can be a vSphere
Standard Switch (VSS) or a vSphere Distributed Switch (VDS).
n
If you use multiple ports for NFS traffic, make sure that you correctly configure your virtual switches
and physical switches.
n
NFS 3 and NFS 4.1 support IPv6.
NFS File Locking
File locking mechanisms are used to restrict access to data stored on a server to only one user or process at a
time. NFS 3 and NFS 4.1 use incompatible file locking mechanisms.
NFS 3 locking on ESXi does not use the Network Lock Manager (NLM) protocol. Instead, VMware provides
its own locking protocol. NFS 3 locks are implemented by creating lock files on the NFS server. Lock files are
named .lck-file_id..
NFS 4.1 uses share reservations as a locking mechanism.
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Because NFS 3 and NFS 4.1 clients do not use the same locking protocol, you cannot use different NFS
versions to mount the same datastore on multiple hosts. Accessing the same virtual disks from two
incompatible clients might result in incorrect behavior and cause data corruption.
NFS Security
With NFS 3 and NFS 4.1, ESXi supports the AUTH_SYS security. In addition, for NFS 4.1, the Kerberos
security mechanism is supported.
NFS 3 supports the AUTH_SYS security mechanism. With this mechanism, storage traffic is transmitted in
an unencrypted format across the LAN. Because of this limited security, use NFS storage on trusted
networks only and isolate the traffic on separate physical switches. You can also use a private VLAN.
NFS 4.1 supports the Kerberos authentication protocol to secure communication with the NFS server.
Nonroot users can access files when Kerberos is used. For more information, see “Using Kerberos for NFS
4.1,” on page 156.
In addition to Kerberos, NFS 4.1 supports traditional non-Kerberos mounts with the AUTH_SYS security. In
this case, use root access guidelines recommended for NFS version 3.
Note You cannot use two security mechanisms, AUTH_SYS and Kerberos, for the same NFS 4.1 datastore
shared by multiple hosts.
NFS Multipathing
While NFS 3 with ESXi does not provide multipathing support, NFS 4.1 supports multiple paths.
NFS 3 uses one TCP connection for I/O. As a result, ESXi supports I/O on only one IP address or hostname
for the NFS server, and does not support multiple paths. Depending on your network infrastructure and
configuration, you can use the network stack to configure multiple connections to the storage targets. In this
case, you must have multiple datastores, each datastore using separate network connections between the
host and the storage.
NFS 4.1 provides multipathing for servers that support the session trunking. When the trunking is available,
you can use multiple IP addresses to access a single NFS volume. Client ID trunking is not supported.
NFS and Hardware Acceleration
Virtual disks created on NFS datastores are thin-provisioned by default. To be able to create thickprovisioned virtual disks, you must use hardware acceleration that supports the Reserve Space operation.
NFS 3 and NFS 4.1 support hardware acceleration that allows your host to integrate with NAS devices and
use several hardware operations that NAS storage provides. For more information, see “Hardware
Acceleration on NAS Devices,” on page 283.
NFS Datastores
When you create an NFS datastore, make sure to follow specific guidelines.
The NFS datastore guidelines and best practices include the following items:
154
n
You cannot use different NFS versions to mount the same datastore on different hosts. NFS 3 and NFS
4.1 clients are not compatible and do not use the same locking protocol. As a result, accessing the same
virtual disks from two incompatible clients might result in incorrect behavior and cause data
corruption.
n
NFS 3 and NFS 4.1 datastores can coexist on the same host.
n
ESXi cannot automatically upgrade NFS version 3 to version 4.1, but you can use other conversion
methods. For information, see “NFS Protocols and ESXi,” on page 150.
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n
When you mount the same NFS 3 volume on different hosts, make sure that the server and folder
names are identical across the hosts. If the names do not match, the hosts see the same NFS version 3
volume as two different datastores. This error might result in a failure of such features as vMotion. An
example of such discrepancy is entering filer as the server name on one host and filer.domain.com on
the other. This guideline does not apply to NFS version 4.1.
n
If you use non-ASCII characters to name datastores and virtual machines, make sure that the
underlying NFS server offers internationalization support. If the server does not support international
characters, use only ASCII characters, or unpredictable failures might occur.
Firewall Configurations for NFS Storage
ESXi includes a firewall between the management interface and the network. The firewall is enabled by
default. At installation time, the ESXi firewall is configured to block incoming and outgoing traffic, except
traffic for the default services, such as NFS.
Supported services, including NFS, are described in a rule set configuration file in the ESXi firewall
directory /etc/vmware/firewall/. The file contains firewall rules and their relationships with ports and
protocols.
The behavior of the NFS Client rule set (nfsClient) is different from other rule sets.
For more information about firewall configurations, see the vSphere Security documentation.
NFS Client Firewall Behavior
The NFS Client firewall rule set behaves differently than other ESXi firewall rule sets. ESXi configures NFS
Client settings when you mount or unmount an NFS datastore. The behavior differs for different versions of
NFS.
When you add, mount, or unmount an NFS datastore, the resulting behavior depends on the version of
NFS.
NFS v3 Firewall Behavior
When you add or mount an NFS v3 datastore, ESXi checks the state of the NFS Client (nfsClient) firewall
rule set.
n
If the nfsClient rule set is disabled, ESXi enables the rule set and disables the Allow All IP Addresses
policy by setting the allowedAll flag to FALSE. The IP address of the NFS server is added to the allowed
list of outgoing IP addresses.
n
If the nfsClient rule set is enabled, the state of the rule set and the allowed IP address policy are not
changed. The IP address of the NFS server is added to the allowed list of outgoing IP addresses.
Note If you manually enable the nfsClient rule set or manually set the Allow All IP Addresses policy,
either before or after you add an NFS v3 datastore to the system, your settings are overridden when the last
NFS v3 datastore is unmounted. The nfsClient rule set is disabled when all NFS v3 datastores are
unmounted.
When you remove or unmount an NFS v3 datastore, ESXi performs one of the following actions.
n
If none of the remaining NFS v3 datastores are mounted from the server of the datastore being
unmounted, ESXi removes the server's IP address from the list of outgoing IP addresses.
n
If no mounted NFS v3 datastores remain after the unmount operation, ESXi disables the nfsClient
firewall rule set.
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NFS v4.1 Firewall Behavior
When you mount the first NFS v4.1 datastore, ESXi enables the nfs41client rule set and sets its allowedAll
flag to TRUE. This action opens port 2049 for all IP addresses. Unmounting an NFS v4.1 datastore does not
affect the firewall state. That is, the first NFS v4.1 mount opens port 2049 and that port remains enabled
unless you close it explicitly.
Verify Firewall Ports for NFS Clients
To enable access to NFS storage, ESXi automatically opens firewall ports for the NFS clients when you
mount an NFS datastore. For troubleshooting reasons, you might need to verify that the ports are open.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Security Profile, and click Edit.
4
Scroll down to an appropriate version of NFS to make sure that the port is opened.
Using Layer 3 Routed Connections to Access NFS Storage
When you use Layer 3 (L3) routed connections to access NFS storage, consider certain requirements and
restructions.
Ensure that your environment meets the following requirements:
n
Use Cisco's Hot Standby Router Protocol (HSRP) in IP Router. If you are using non-Cisco router, be sure
to use Virtual Router Redundancy Protocol (VRRP) instead.
n
Use Quality of Service (QoS) to prioritize NFS L3 traffic on networks with limited bandwidths, or on
networks that experience congestion. See your router documentation for details.
n
Follow Routed NFS L3 best practices recommended by storage vendor. Contact your storage vendor for
details.
n
Disable Network I/O Resource Management (NetIORM).
n
If you are planning to use systems with top-of-rack switches or switch-dependent I/O device
partitioning, contact your system vendor for compatibility and support.
In an L3 environment the following restrictions apply:
n
The environment does not support VMware Site Recovery Manager.
n
The environment supports only the NFS protocol. Do not use other storage protocols such as FCoE over
the same physical network.
n
The NFS traffic in this environment does not support IPv6.
n
The NFS traffic in this environment can be routed only over a LAN. Other environments such as WAN
are not supported.
Using Kerberos for NFS 4.1
With NFS version 4.1, ESXi supports the Kerberos authentication mechanism.
The RPCSEC_GSS Kerberos mechanism is an authentication service. It allows an NFS 4.1 client installed on
ESXi to prove its identity to an NFS server before mounting an NFS share. The Kerberos security uses
cryptography to work across an insecure network connection.
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The ESXi implementation of Kerberos for NFS 4.1 provides two security models, krb5 and krb5i, that offer
different levels of security.
n
Kerberos for authentication only (krb5) supports identity verification.
n
Kerberos for authentication and data integrity (krb5i), in addition to identity verification, provides data
integrity services. These services help to protect the NFS traffic from tampering by checking data
packets for any potential modifications.
Kerberos supports cryptographic algorithms that prevent unauthorized users from gaining access to NFS
traffic. The NFS 4.1 client on ESXi attempts to use either the AES256-CTS-HMAC-SHA1-96 or AES128-CTSHMAC-SHA1-96 algorithm to access a share on the NAS server. Before using your NFS 4.1 datastores, make
sure that AES256-CTS-HMAC-SHA1-96 or AES128-CTS-HMAC-SHA1-96 are enabled on the NAS server.
The following table compares Kerberos security levels that ESXi supports.
Table 16‑5. Types of Kerberos Security
Kerberos for authentication
only (krb5)
Kerberos for authentication
and data integrity (krb5i)
ESXi 6.0
ESXi 6.5
Integrity checksum for
RPC header
Yes with DES
Yes with AES
Integrate checksum for
RPC data
No
No
Integrity checksum for
RPC header
No krb5i
Yes with AES
Integrate checksum for
RPC data
Yes with AES
When you use Kerberos authentication, the following considerations apply:
n
ESXi uses Kerberos with the Active Directory domain.
n
As a vSphere administrator, you specify Active Directory credentials to provide access to NFS 4.1
Kerberos datastores for an NFS user. A single set of credentials is used to access all Kerberos datastores
mounted on that host.
n
When multiple ESXi hosts share the NFS 4.1 datastore, you must use the same Active Directory
credentials for all hosts that access the shared datastore. To automate the assignment process, set the
user in host profiles and apply the profile to all ESXi hosts.
n
You cannot use two security mechanisms, AUTH_SYS and Kerberos, for the same NFS 4.1 datastore
shared by multiple hosts.
Set Up NFS Storage Environment
You must perform several configuration steps before you mount an NFS datastore in vSphere.
Prerequisites
n
Familiarize yourself with the guidelines in “NFS Storage Guidelines and Requirements,” on page 152.
n
For details on configuring NFS storage, consult your storage vendor documentation.
n
If you use Kerberos, make sure that AES256-CTS-HMAC-SHA1-96 or AES128-CTS-HMAC-SHA1-96 are
enabled on the NAS server.
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Procedure
1
On the NFS server, configure an NFS volume and export it to be mounted on the ESXi hosts.
a
Note the IP address or the DNS name of the NFS server and the full path, or folder name, for the
NFS share.
For NFS 4.1, you can collect multiple IP addresses or DNS names to use the multipathing support
that the NFS 4.1 datastore provides.
b
2
If you plan to use Kerberos authentication with NFS 4.1, specify the Kerberos credentials to be used
by ESXi for authentication.
On each ESXi host, configure a VMkernel Network port for NFS traffic.
For more information, see the vSphere Networking documentation.
3
If you plan to use Kerberos authentication with the NFS 4.1 datastore, configure the ESXi hosts for
Kerberos authentication.
See “Configure ESXi Hosts for Kerberos Authentication,” on page 158.
What to do next
You can now create an NFS datastore on the ESXi hosts.
Configure ESXi Hosts for Kerberos Authentication
If you use NFS 4.1 with Kerberos, you must perform several tasks to set up your hosts for Kerberos
authentication.
When multiple ESXi hosts share the NFS 4.1 datastore, you must use the same Active Directory credentials
for all hosts that access the shared datastore. You can automate the assignment process by setting the user in
host profiles and applying the profile to all ESXi hosts.
Prerequisites
n
Make sure that Microsoft Active Directory (AD) and NFS servers are configured to use Kerberos.
n
Enable AES256-CTS-HMAC-SHA1-96 or AES128-CTS-HMAC-SHA1-96 encryption modes on AD. The
NFS 4.1 client does not support the DES-CBC-MD5 encryption mode.
n
Make sure that the NFS server exports are configured to grant full access to the Kerberos user.
Procedure
1
Configure DNS for NFS 4.1 with Kerberos on page 159
When you use NFS 4.1 with Kerberos, you must change the DNS settings on ESXi hosts. The settings
must point to the DNS server that is configured to hand out DNS records for the Kerberos Key
Distribution Center (KDC). For example, use the Active Directory server address if AD is used as a
DNS server.
2
Configure Network Time Protocol for NFS 4.1 with Kerberos on page 159
If you use NFS 4.1 with Kerberos, configure Network Time Protocol (NTP) to make sure all ESXi hosts
on the vSphere network are synchronized.
3
Enable Kerberos Authentication in Active Directory on page 159
If you use NFS 4.1 storage with Kerberos, you must add each ESXi host to an Active Directory domain
and enable Kerberos authentication. Kerberos integrates with Active Directory to enable single sign-on
and provides an extra layer of security when used across an insecure network connection.
What to do next
After you configure your host for Kerberos, you can create an NFS 4.1 datastore with Kerberos enabled.
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Configure DNS for NFS 4.1 with Kerberos
When you use NFS 4.1 with Kerberos, you must change the DNS settings on ESXi hosts. The settings must
point to the DNS server that is configured to hand out DNS records for the Kerberos Key Distribution
Center (KDC). For example, use the Active Directory server address if AD is used as a DNS server.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Networking, click TCP/IP configuration, and click the Edit icon.
4
Enter the DNS setting information.
Option
Description
Domain
AD Domain Name
Preferred DNS server
AD Server IP
Search domains
AD Domain Name
Configure Network Time Protocol for NFS 4.1 with Kerberos
If you use NFS 4.1 with Kerberos, configure Network Time Protocol (NTP) to make sure all ESXi hosts on
the vSphere network are synchronized.
The best practice is to use the Active Domain server as the NTP server.
Procedure
1
Select the host in the vSphere inventory.
2
Click the Configure tab.
3
Under System, select Time Configuration.
4
Click Edit and set up the NTP server.
5
a
Select Use Network Time Protocol (Enable NTP client).
b
Set the NTP Service Startup Policy.
c
To synchronize with the NTP server, enter its IP addresses.
d
Click Start or Restart in the NTP Service Status section.
Click OK.
The host synchronizes with the NTP server.
Enable Kerberos Authentication in Active Directory
If you use NFS 4.1 storage with Kerberos, you must add each ESXi host to an Active Directory domain and
enable Kerberos authentication. Kerberos integrates with Active Directory to enable single sign-on and
provides an extra layer of security when used across an insecure network connection.
Prerequisites
Set up an AD domain and a domain administrator account with the rights to add hosts to the domain.
Procedure
1
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2
Click the Configure tab.
3
Under System, click Authentication Services.
4
Add the ESXi host to an Active Directory domain.
a
In the Authentication Services pane, click Join Domain.
b
Supply the domain settings, and click OK.
The directory services type changes to Active Directory.
5
Configure or edit credentials for an NFS Kerberos user.
a
In the NFS Kerberos Credentials pane, click Edit.
b
Enter a user name and password.
Files stored in all Kerberos datastores are accessed using these credentials.
The state for NFS Kerberos credentials changes to Enabled.
Creating Datastores
You use the New Datastore wizard to create your datastores. Depending on the type of storage you have in
your environment and your storage needs, you can create a VMFS, NFS, or Virtual Volumes datastore.
A Virtual SAN datastore is automatically created when you enable Virtual SAN. For information, see the
Administering VMware Virtual SAN documentation.
You can also use the New Datastore wizard to manage VMFS datastore copies.
n
Create a VMFS Datastore on page 160
VMFS datastores serve as repositories for virtual machines. You can set up VMFS datastores on any
SCSI-based storage devices that the host discovers, including Fibre Channel, iSCSI, and local storage
devices.
n
Create an NFS Datastore on page 162
You can use the New Datastore wizard to mount an NFS volume.
n
Create a Virtual Volumes Datastore on page 162
You use the New Datastore wizard to create a Virtual Volumes datastore.
Create a VMFS Datastore
VMFS datastores serve as repositories for virtual machines. You can set up VMFS datastores on any SCSIbased storage devices that the host discovers, including Fibre Channel, iSCSI, and local storage devices.
Note You cannot create VMFS3 datastores on the ESXi hosts. Existing VMFS3 datastores continue to be
available and usable, so that you can migrate your virtual machines to VMFS5 or VMFS6 datastores.
Prerequisites
1
Install and configure any adapters that your storage requires.
2
To discover newly added storage devices, perform a rescan. See “Storage Rescan Operations,” on
page 120.
3
Verify that storage devices you are planning to use for your datastores are available. See “Storage
Device Characteristics,” on page 18.
Procedure
1
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In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
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2
Click the New Datastore icon.
3
Type the datastore name and if necessary, select the placement location for the datastore.
The vSphere Web Client enforces a 42 character limit for the datastore name.
4
Select VMFS as the datastore type.
5
Select the device to use for your datastore.
Important The device you select must not have any values displayed in the Snapshot Volume
column. If a value is present, the device contains a copy of an existing VMFS datastore. For information
on managing datastore copies, see “Managing Duplicate VMFS Datastores,” on page 163.
6
7
Specify the datastore version.
Option
Description
VMFS6
This option is default for 512e storage devices. The ESXi hosts of version
6.0 or earlier cannot recognize the VMFS6 datastore. If your cluster
includes ESXi 6.0 and ESXi 6.5 hosts that share the datastore, this version
might not be appropriate.
VMFS5
This option is default for 512n storage devices. VMFS5 datastore supports
access by the ESXi hosts of version 6.5 or earlier.
Define configuration details for the datastore.
a
b
Specify partition configuration.
Option
Description
Use all available partitions
Dedicates the entire disk to a single VMFS datastore. If you select this
option, all file systems and data currently stored on this device are
destroyed.
Use free space
Deploys a VMFS datastore in the remaining free space of the disk.
If the space allocated for the datastore is excessive for your purposes, adjust the capacity values in
the Datastore Size field.
By default, the entire free space on the storage device is allocated.
c
8
For VMFS6, specify the block size and define space reclamation parameters.
Option
Description
Block size
The block size on a VMFS datastore defines the maximum file size and
the amount of space the file occupies. VMFS6 supports the block size of
1 MB.
Space reclamation granularity
Specify granularity for the unmap operation. Unmap granularity
equals the block size, which is 1 MB.
Storage sectors of the size smaller than 1 MB are not reclaimed.
Space reclamation priority
Select one of the following options.
n Low (default). Process the unmap operations at a low rate.
n None. Select this option if you want to disable the space
reclamation operations for the datastore.
In the Ready to Complete page, review the datastore configuration information and click Finish.
The datastore on the SCSI-based storage device is created. It is available to all hosts that have access to the
device.
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Create an NFS Datastore
You can use the New Datastore wizard to mount an NFS volume.
Prerequisites
n
Set up NFS storage environment.
n
If you plan to use Kerberos authentication with the NFS 4.1 datastore, make sure to configure the ESXi
hosts for Kerberos authentication.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the New Datastore icon.
3
Type the datastore name and if necessary, select the placement location for the datastore.
The vSphere Web Client enforces a 42 character limit for the datastore name.
4
Select NFS as the datastore type.
5
Specify an NFS version.
n
NFS 3
n
NFS 4.1
Important If multiple hosts access the same datastore, you must use the same protocol on all hosts.
6
Type the server name or IP address and the mount point folder name.
You can use IPv6 or IPv4 formats.
With NFS 4.1, you can add multiple IP addresses or server names if the NFS server supports trunking.
The ESXi host uses these values to achieve multipathing to the NFS server mount point.
7
Select Mount NFS read only if the volume is exported as read-only by the NFS server.
8
To use Kerberos security with NFS 4.1, enable Kerberos and select an appropriate Kerberos model.
Option
Description
Use Kerberos for authentication
only (krb5)
Supports identity verification
Use Kerberos for authentication
and data integrity (krb5i)
In addition to identity verification, provides data integrity services. These
services help to protect the NFS traffic from tampering by checking data
packets for any potential modifications.
If you do not enable Kerberos, the datastore uses the default AUTH_SYS security.
9
If you are creating a datastore at the data center or cluster level, select hosts that mount the datastore.
10
Review the configuration options and click Finish.
Create a Virtual Volumes Datastore
You use the New Datastore wizard to create a Virtual Volumes datastore.
Procedure
162
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the New Datastore icon.
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3
Specify the placement location for the datastore.
4
Select VVol as the datastore type.
5
From the list of storage containers, select a backing storage container and type the datastore name.
Make sure to use the name that does not duplicate another datastore name in your data center
environment.
If you mount the same Virtual Volumes datastore to several hosts, the name of the datastore must be
consistent across all hosts.
6
Select the hosts that require access to the datastore.
7
Review the configuration options and click Finish.
What to do next
After you create the Virtual Volumes datastore, you can perform such datastore operations as renaming the
datastore, browsing datastore files, unmounting the datastore, and so on.
You cannot add the Virtual Volumes datastore to a datastore cluster.
Managing Duplicate VMFS Datastores
When a storage device contains a VMFS datastore copy, you can mount the datastore with the existing
signature or assign a new signature.
Each VMFS datastore created in a storage disk has a unique signature, also called UUID, that is stored in the
file system superblock. When the storage disk is replicated or its snapshot is taken on the storage side, the
resulting disk copy is identical, byte-for-byte, with the original disk. As a result, if the original storage disk
contains a VMFS datastore with UUID X, the disk copy appears to contain a datastore copy with the same
UUID X.
In addition to LUN snapshotting and replication, the following device operations cause ESXi to mark the
datastore on the device as a copy of the original datastore:
n
LUN ID changes
n
SCSI device type changes, for example, from SCSI-2 to SCSI-3
n
SPC-2 compliancy enablement
ESXi can detect the VMFS datastore copy and display it in the vSphere Web Client. You have an option of
mounting the datastore copy with its original UUID or changing the UUID to resignature the datastore.
Whether you chose resignaturing or mounting without resignaturing depends on how the LUNs are
masked in the storage environment. If your hosts are able to see both copies of the LUN, then resignaturing
is the recommended method. Otherwise, mounting is an option.
Keep Existing Datastore Signature
If you do not need to resignature a VMFS datastore copy, you can mount it without changing its signature.
You can keep the signature if, for example, you maintain synchronized copies of virtual machines at a
secondary site as part of a disaster recovery plan. In the event of a disaster at the primary site, you mount
the datastore copy and power on the virtual machines at the secondary site.
Prerequisites
n
Perform a storage rescan on your host to update the view of storage devices presented to the host.
n
Unmount the original VMFS datastore that has the same UUID as the copy you plan to mount. You can
mount the VMFS datastore copy only if it does not collide with the original VMFS datastore.
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Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the New Datastore icon.
3
Type the datastore name and if necessary, select the placement location for the datastore.
4
Select VMFS as the datastore type.
5
From the list of storage devices, select the device that has a specific value displayed in the Snapshot
Volume column.
The value present in the Snapshot Volume column indicates that the device is a copy that contains a
copy of an existing VMFS datastore.
6
Under Mount Options, select Keep Existing Signature.
7
Review the datastore configuration information and click Finish.
What to do next
If you later want to resignature the mounted datastore, you must unmount it first.
Resignature a VMFS Datastore Copy
Use datastore resignaturing if you want to retain the data stored on the VMFS datastore copy.
When resignaturing a VMFS copy, ESXi assigns a new signature (UUID) to the copy, and mounts the copy as
a datastore distinct from the original. All references to the original signature from virtual machine
configuration files are updated.
When you perform datastore resignaturing, consider the following points:
n
Datastore resignaturing is irreversible.
n
After resignaturing, the storage device replica that contained the VMFS copy is no longer treated as a
replica.
n
A spanned datastore can be resignatured only if all its extents are online.
n
The resignaturing process is crash and fault tolerant. If the process is interrupted, you can resume it
later.
n
You can mount the new VMFS datastore without a risk of its UUID conflicting with UUIDs of any other
datastore, such as an ancestor or child in a hierarchy of storage device snapshots.
Prerequisites
n
Unmount the datastore copy.
n
Perform a storage rescan on your host to update the view of storage devices presented to the host.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the New Datastore icon.
3
Type the datastore name and if necessary, select the placement location for the datastore.
4
Select VMFS as the datastore type.
5
From the list of storage devices, select the device that has a specific value displayed in the Snapshot
Volume column.
The value present in the Snapshot Volume column indicates that the device is a copy that contains a
copy of an existing VMFS datastore.
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6
Under Mount Options, select Assign a New Signature and click Next.
7
Review the datastore configuration information and click Finish.
Increasing VMFS Datastore Capacity
If your VMFS datastore requires more space, increase the datastore capacity. You can dynamically increase
the capacity by growing a datastore extent or by adding an extent.
Use one of the following methods to increase the datastore capacity:
n
Dynamically grow any expandable datastore extent, so that it fills the available adjacent capacity. The
extent is considered expandable when the underlying storage device has free space immediately after
the extent.
n
Dynamically add the extent. The datastore can span over up to 32 extents with the size of each extent of
more than 2 TB, yet appear as a single volume. The spanned VMFS datastore can use any or all its
extents at any time. It does not need to fill up a particular extent before using the next one.
Note Datastores that support only the hardware assisted locking, also called the atomic test and set
(ATS) mechanism, cannot span over non-ATS devices. For more information, see “VMFS Locking
Mechanisms,” on page 146.
Increase VMFS Datastore Capacity
When you need to add virtual machines to a datastore, or when the virtual machines running on a datastore
require more space, you can dynamically increase the capacity of a VMFS datastore.
If a shared datastore has powered on virtual machines and becomes 100% full, you can increase the
datastore's capacity only from the host with which the powered on virtual machines are registered.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Select the datastore to grow and click the Increase Datastore Capacity icon.
3
Select a device from the list of storage devices.
Your selection depends on whether an expandable storage device is available.
4
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Option
Description
To expand an existing extent
Select the device for which the Expandable column reads YES. A storage
device is expandable when it has free space immediately after the extent.
To add a new extent
Select the device for which the Expandable column reads NO.
Review the Partition Layout to see the available configurations.
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5
Select a configuration option from the bottom panel.
Depending on the current layout of the disk and on your previous selections, the options you see might
vary.
6
Option
Description
Use free space to expand the
datastore
Expands an existing extent to a required capacity.
Use free space
Deploys an extent in the remaining free space of the disk. This option is
available only when you are adding an extent.
Use all available partitions
Dedicates the entire disk to a single extent. This option is available only
when you are adding an extent and when the disk you are formatting is
not blank. The disk is reformatted, and the datastores and any data that it
contains are erased.
Set the capacity for the extent.
The minimum extent size is 1.3 GB. By default, the entire free space on the storage device is available.
7
Click Next.
8
Review the proposed layout and the new configuration of your datastore, and click Finish.
Administrative Operations for Datastores
After creating datastores, you can perform several administrative operations on the datastores. Certain
operations, such as renaming a datastore, are available for all types of datastores. Others apply to specific
types of datastores.
n
Change Datastore Name on page 167
You can change the name of an existing datastore.
n
Unmount Datastores on page 167
When you unmount a datastore, it remains intact, but can no longer be seen from the hosts that you
specify. The datastore continues to appear on other hosts, where it remains mounted.
n
Mount Datastores on page 168
You can mount a datastore you previously unmounted. You can also mount a datastore on additional
hosts, so that it becomes a shared datastore.
n
Remove VMFS Datastores on page 168
You can delete any type of VMFS datastore, including copies that you have mounted without
resignaturing. When you delete a datastore, it is destroyed and disappears from all hosts that have
access to the datastore.
n
Use Datastore Browser on page 169
Use the datastore file browser to manage contents of your datastores. You can browse folders and files
that are stored on the datastore. You can also use the browser to upload files and perform
administrative tasks on your folders and files.
n
Turn off Storage Filters on page 172
When you perform VMFS datastore management operations, vCenter Server uses default storage
protection filters. The filters help you to avoid storage corruption by retrieving only the storage
devices that can be used for a particular operation. Unsuitable devices are not displayed for selection.
You can turn off the filters to view all devices.
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Change Datastore Name
You can change the name of an existing datastore.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Right-click the datastore to rename, and select Rename.
3
Type a new datastore name.
The vSphere Web Client enforces a 42 character limit for the datastore name.
The new name appears on all hosts that have access to the datastore.
Unmount Datastores
When you unmount a datastore, it remains intact, but can no longer be seen from the hosts that you specify.
The datastore continues to appear on other hosts, where it remains mounted.
Do not perform any configuration operations that might result in I/O to the datastore while the unmount is
in progress.
Note Make sure that the datastore is not used by vSphere HA heartbeating. vSphere HA heartbeating does
not prevent you from unmounting the datastore. However, if the datastore is used for heartbeating,
unmounting it might cause the host to fail and restart any active virtual machine.
Prerequisites
When appropriate, before unmounting datastores, make sure that the following prerequisites are met:
n
No virtual machines reside on the datastore.
n
The datastore is not managed by Storage DRS.
n
Storage I/O control is disabled for this datastore.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Right-click the datastore to unmount and select Unmount Datastore.
3
If the datastore is shared, specify which hosts should no longer access the datastore.
4
Confirm that you want to unmount the datastore.
After you unmount a VMFS datastore from all hosts, the datastore is marked as inactive. If you unmount an
NFS or a virtual volumes datastore from all hosts, the datastore disappears from the inventory. You can
mount the unmounted VMFS datastore. To mount the NFS or virtual volumes datastore that has been
removed from the inventory, use the New Datastore wizard.
What to do next
If you unmounted the VMFS datastore as a part of an orderly storage removal procedure, you can now
detach the storage device that is backing the datastore. See “Detach Storage Devices,” on page 124.
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Mount Datastores
You can mount a datastore you previously unmounted. You can also mount a datastore on additional hosts,
so that it becomes a shared datastore.
A VMFS datastore that has been unmounted from all hosts remains in inventory, but is marked as
inaccessible. You can use this task to mount the VMFS datastore to a specified host or multiple hosts.
If you have unmounted an NFS or a Virtual Volumes datastore from all hosts, the datastore disappears from
the inventory. To mount the NFS or Virtual Volumes datastore that has been removed from the inventory,
use the New Datastore wizard.
A datastore of any type that is unmounted from some hosts while being mounted on others, is shown as
active in the inventory.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Right-click the datastore to mount and select one of the following options:
n
Mount Datastore
n
Mount Datastore on Additional Hosts
Whether you see one or another option depends on the type of datastore you use.
3
Select the hosts that should access the datastore.
Remove VMFS Datastores
You can delete any type of VMFS datastore, including copies that you have mounted without resignaturing.
When you delete a datastore, it is destroyed and disappears from all hosts that have access to the datastore.
Note The datastore delete operation permanently deletes all files associated with virtual machines on the
datastore. Although you can delete the datastore without unmounting, it is preferable that you unmount the
datastore first.
Prerequisites
n
Remove or migrate all virtual machines from the datastore.
n
Make sure that no other host is accessing the datastore.
n
Disable Storage DRS for the datastore.
n
Disable Storage I/O control for the datastore.
n
Make sure that the datastore is not used for vSphere HA heartbeating.
Procedure
168
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Right-click the datastore to remove, and select Delete Datastore.
3
Confirm that you want to remove the datastore.
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Use Datastore Browser
Use the datastore file browser to manage contents of your datastores. You can browse folders and files that
are stored on the datastore. You can also use the browser to upload files and perform administrative tasks
on your folders and files.
Procedure
1
Open the datastore browser.
a
Display the datastore in the inventory.
b
Right-click the datastore and select Browse Files (
).
2
Explore the contents of the datastore by navigating to existing folders and files.
3
Perform administrative tasks by using the icons and options.
Icons and Options
Descriptions
Upload a file to the datastore. See “Upload Files to Datastores,” on
page 169.
Download from the datastore. See “Download Files from Datastores,” on
page 170.
Create a folder on the datastore.
Copy selected folders or files to a new location, either on the same
datastore or on a different datastore. See “Copy Datastore Folders or
Files,” on page 170.
Move selected folders or files to a new location, either on the same
datastore or on a different datastore. See “Move Datastore Folders or
Files,” on page 171.
Rename selected folders or files. See “Rename Datastore Folders or Files,”
on page 171.
Delete selected folders or files.
Inflate
Convert a selected thin virtual disk to thick. This option applies only to
thin-provisioned disks. See “Inflate Thin Virtual Disks,” on page 290.
Upload Files to Datastores
Use the datastore file browser to upload files to datastores accessible to ESXi hosts.
In addition to their traditional use as storage for virtual machines files, datastores can serve to store data or
files related to virtual machines. For example, you can upload ISO images of operating systems from a local
computer to a datastore on the host. You then use these images to install guest operating systems on the new
virtual machines.
Note Virtual Volumes do not support uploading files directly to the Virtual Volumes datastores. You must
first create a folder on the Virtual Volumes datastore, and then upload the files into the folder.
Prerequisites
Required privilege: Datastore.Browse Datastore
Procedure
1
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Open the datastore browser.
a
Display the datastore in the inventory.
b
Right-click the datastore and select Browse Files (
).
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2
(Optional) Create a folder to store the file.
3
Select the target folder and click the Upload a file to the datastore icon ( ).
4
Locate the item to upload on the local computer and click Open.
5
Refresh the datastore file browser to see the uploaded file on the list.
What to do next
You might experience problems when deploying an OVF template that you previously exported and then
uploaded to a datastore. For details and a workaround, see the VMware Knowledge Base article 2117310.
Download Files from Datastores
Use the datastore file browser to download files from the datastore available on your ESXi host to your local
computer.
Prerequisites
Required privilege: Datastore.Browse Datastore
Procedure
1
Open the datastore browser.
a
Display the datastore in the inventory.
b
Right-click the datastore and select Browse Files (
).
2
Navigate to the file to download and click the Download from Datastore icon ( ).
3
Follow the prompts to save the file to your local computer.
Copy Datastore Folders or Files
Use the datastore browser to copy folders or files to a new location, either on the same datastore or on a
different datastore.
Virtual disk files are moved or copied without format conversion. However, if a target datastore belongs to a
host different from the source host, you might need to convert the virtual disk. Otherwise, you might fail to
use the disk.
You cannot copy VM files across vCenter Servers.
Prerequisites
Required privilege: Datastore.Browse Datastore
Procedure
1
2
3
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Open the datastore browser.
a
Display the datastore in the inventory.
b
Right-click the datastore and select Browse Files (
).
Browse to an object you want to copy, either a folder or a file.
Select the object and click the Copy selection to a new location (
) icon.
4
Specify the destination location.
5
(Optional) Select the Overwrite files and folders with matching names at the destination check box.
6
Click OK.
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Move Datastore Folders or Files
Use the datastore browser to move folders or files to a new location, either on the same datastore or on a
different datastore.
Note Virtual disk files are moved or copied without format conversion. If you move a virtual disk to a
datastore that belongs to a host different from the source host, you might need to convert the virtual disk.
Otherwise, you might not be able to use the disk.
Prerequisites
Required privilege: Datastore.Browse Datastore
Procedure
1
Open the datastore browser.
a
Display the datastore in the inventory.
b
Right-click the datastore and select Browse Files (
).
2
Browse to an object you want to move, either a folder or a file.
3
Select the object and click the Move selection to a new location icon.
4
Specify the destination location.
5
(Optional) Select Overwrite files and folders with matching names at the destination.
6
Click OK.
Rename Datastore Folders or Files
Use the datastore browser to rename folders or files.
Prerequisites
Required privilege: Datastore.Browse Datastore
Procedure
1
Open the datastore browser.
a
Display the datastore in the inventory.
b
Right-click the datastore and select Browse Files (
).
2
Browse to an object you want to rename, either a folder or a file.
3
Select the object and click the Rename selection icon.
4
Specify the new name and click OK.
Inflate Thin Virtual Disks
If you created a virtual disk in the thin format, you can convert the thin disk to a virtual disk in thick
provision format.
You use the datastore browser to inflate the virtual disk.
Prerequisites
n
Make sure that the datastore where the virtual machine resides has enough space.
n
Make sure that the virtual disk is thin.
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n
Remove snapshots.
n
Power off your virtual machine.
Procedure
1
Navigate to the folder of the virtual disk you want to inflate.
a
In the vSphere Web Client, browse to the virtual machine.
b
Click the Datastores tab.
The datastore that stores the virtual machine files is listed.
c
Select the datastore and click the Browse Files icon (
).
The datastore browser displays contents of the datastore.
2
Expand the virtual machine folder and browse to the virtual disk file that you want to convert.
The file has the .vmdk extension and is marked with the virtual disk (
3
) icon.
Right-click the virtual disk file and select Inflate.
Note The option might not be available if the virtual disk is thick or when the virtual machine is
running.
The inflated virtual disk occupies the entire datastore space originally provisioned to it.
Turn off Storage Filters
When you perform VMFS datastore management operations, vCenter Server uses default storage protection
filters. The filters help you to avoid storage corruption by retrieving only the storage devices that can be
used for a particular operation. Unsuitable devices are not displayed for selection. You can turn off the filters
to view all devices.
Prerequisites
Before you make changes to the device filters, consult with the VMware support team. You can turn off the
filters only if you have other methods to prevent device corruption.
Procedure
1
Browse to the vCenter Server in the vSphere Web Client object navigator.
2
Click the Configure tab.
3
Under Settings, click Advanced Settings, and click Edit.
4
Specify the filter to turn off.
a
b
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In the Name text box, enter an appropriate filter name.
Name
Description
config.vpxd.filter.vmfsFilter
VMFS Filter
config.vpxd.filter.rdmFilter
RDM Filter
config.vpxd.filter.SameHostsAndT
ransportsFilter
Same Hosts and Transports Filter
config.vpxd.filter.hostRescanFilter
Host Rescan Filter
Note If you turn off the Host Rescan Filter, your hosts continue to
perform a rescan each time you present a new LUN to a host or a
cluster.
In the Value text box, enter False for the specified key.
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5
Click Add, and click OK to save your changes.
You are not required to restart the vCenter Server system.
Storage Filtering
vCenter Server provides storage filters to help you avoid storage device corruption or performance
degradation that might be caused by an unsupported use of storage devices. These filters are available by
default.
Table 16‑6. Storage Filters
Filter Name
Description
config.vpxd.filter.vmfsFilter
(VMFS Filter)
Filters out storage devices, or LUNs, that are already used by a VMFS datastore on any
host managed by vCenter Server. The LUNs do not show up as candidates to be
formatted with another VMFS datastore or to be used as an RDM.
config.vpxd.filter.rdmFilter
(RDM Filter)
Filters out LUNs that are already referenced by an RDM on any host managed by vCenter
Server. The LUNs do not show up as candidates to be formatted with VMFS or to be used
by a different RDM.
For your virtual machines to access the same LUN, the virtual machines must share the
same RDM mapping file. For information about this type of configuration, see the vSphere
Resource Management documentation.
config.vpxd.filter.SameHostsAndTrans
portsFilter
(Same Hosts and Transports Filter)
Filters out LUNs ineligible for use as VMFS datastore extents because of host or storage
type incompatibility. Prevents you from adding the following LUNs as extents:
n LUNs not exposed to all hosts that share the original VMFS datastore.
n LUNs that use a storage type different from the one the original VMFS datastore uses.
For example, you cannot add a Fibre Channel extent to a VMFS datastore on a local
storage device.
config.vpxd.filter.hostRescanFilter
(Host Rescan Filter)
Automatically rescans and updates VMFS datastores after you perform datastore
management operations. The filter helps provide a consistent view of all VMFS datastores
on all hosts managed by vCenter Server.
Note If you present a new LUN to a host or a cluster, the hosts automatically perform a
rescan no matter whether you have the Host Rescan Filter on or off.
Set Up Dynamic Disk Mirroring
Typically, you cannot use logical-volume manager software on virtual machines to mirror virtual disks.
However, if your Microsoft Windows virtual machines support dynamic disks, you can protect the virtual
machines from an unplanned storage device loss by mirroring virtual disks across two SAN LUNs.
Prerequisites
n
Use a Windows virtual machine that supports dynamic disks.
n
Required privilege: Advanced
Procedure
1
Create a virtual machine with two virtual disks.
Make sure to place the disks on different datastores.
2
Log in to your virtual machine and configure the disks as dynamic mirrored disks.
See Microsoft documentation.
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4
Change virtual machine settings to allow the use of dynamic disk mirroring.
a
Right-click the virtual machine and select Edit Settings.
b
Click the VM Options tab and expand the Advanced menu.
c
Click Edit Configuration next to Configuration Parameters.
d
Click Add Row and add the following parameters:
e
Name
Value
scsi#.returnNoConnectDuringAPD
True
scsi#.returnBusyOnNoConnectStatus
False
Click OK.
Collecting Diagnostic Information for ESXi Hosts on a Storage Device
During a host failure, ESXi must be able to save diagnostic information to a preconfigured location for
diagnostic and technical support purposes.
Typically, a partition to collect diagnostic information, also called VMkernel core dump, is created on a local
storage device during ESXi installation. You can override this default behavior if, for example, you use
shared storage devices instead of local storage. To prevent automatic formatting of local devices, detach the
devices from the host before you install ESXi and power on the host for the first time. You can later set up a
location for collecting diagnostic information on a local or remote storage device.
When you use storage devices, you can select between two options of setting up core dump collection. You
can use a preconfigured diagnostic partition on a storage device or use a file on a VMFS datastore.
n
Set Up a Device Partition as Core Dump Location on page 174
Create a diagnostic partition for your ESXi host.
n
Set Up a File as Core Dump Location on page 175
If the size of your available core dump partition is insufficient, you can configure ESXi to generate core
dump as a file.
Set Up a Device Partition as Core Dump Location
Create a diagnostic partition for your ESXi host.
When you create a diagnostic partition, the following considerations apply:
n
You cannot create a diagnostic partition on an iSCSI LUN accessed through the software iSCSI or
dependent hardware iSCSI adapter. For more information about diagnostic partitions with iSCSI, see
“General Boot from iSCSI SAN Recommendations,” on page 103.
n
You cannot create a diagnostic partition on a software FCoE LUN.
n
Unless you are using diskless servers, set up a diagnostic partition on a local storage.
n
Each host must have a diagnostic partition of 2.5 GB. If multiple hosts share a diagnostic partition on a
SAN LUN, the partition should be large enough to accommodate core dumps of all hosts.
n
If a host that uses a shared diagnostic partition fails, reboot the host and extract log files immediately
after the failure. Otherwise, the second host that fails before you collect the diagnostic data of the first
host might not be able to save the core dump.
Procedure
1
174
Browse to the host in the vSphere Web Client navigator.
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2
Right-click the host, and select Add Diagnostic Partition.
If you do not see this option, the host already has a diagnostic partition.
3
Specify the type of diagnostic partition.
Option
Description
Private local
Creates the diagnostic partition on a local disk. This partition stores fault
information only for your host.
Private SAN storage
Creates the diagnostic partition on a non-shared SAN LUN. This partition
stores fault information only for your host.
Shared SAN storage
Creates the diagnostic partition on a shared SAN LUN. This partition is
accessed by multiple hosts and can store fault information for more than
one host.
4
Click Next.
5
Select the device to use for the diagnostic partition and click Next.
6
Review the partition configuration information and click Finish.
Verify a Diagnostic Partition
Use the esxcli command to verify whether a diagnostic partition is set.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
List partitions to verify that a diagnostic partition is set.
esxcli --server=server_name system coredump partition list
If a diagnostic partition is set, the command displays information about it. Otherwise, the command shows
that no partition is activated and configured.
What to do next
To mange the host’s diagnostic partition, use the vCLI commands. See vSphere Command-Line Interface
Concepts and Examples.
Set Up a File as Core Dump Location
If the size of your available core dump partition is insufficient, you can configure ESXi to generate core
dump as a file.
Typically, a core dump partition of 2.5 GB is created during ESXi installation. For upgrades from ESXi 5.0
and earlier, the core dump partition is limited to 100 MB. For this type of upgrade, during the boot process
the system might create a core dump file on a VMFS datastore. If it does not create a core dump file, you can
manually create the file.
Note Software iSCSI and software FCoE are not supported for core dump file locations.
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Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Create a VMFS datastore core dump file by running the following command:
esxcli system coredump file add
The command takes the following options, but they are not required and can be omitted:
2
Option
Description
--datastore | -d datastore_UUID or
datastore_name
If not provided, the system selects a datastore of sufficient size.
--file | -f file_name
If not provided, the system specifies a unique name for the core dump file.
--size |-s file_size_MB
If not provided, the system creates a file of the size appropriate for the
memory installed in the host.
Verify that the file has been created:
esxcli system coredump file list
You can see the output similar to the following:
Path
Active Configured Size
------------------------------------------------ ------ ---------- --------/vmfs/volumes/52b021c3-.../vmkdump/test.dumpfile false false
104857600
3
Activate the core dump file for the host:
esxcli system coredump file set
The command takes the following options:
Option
Description
--path | -p
The path of the core dump file to use. This must be a pre-allocated file.
--smart | -s
This flag can be used only with --enable | -e=true. It will cause the file to be
selected using the smart selection algorithm.
For example,
esxcli system coredump file set --smart --enable true
4
Verify that the core dump file is active and configured:
esxcli system coredump file list
The output similar to the following indicates that the core dump file is active and configured:
Path
Active Configured Size
------------------------------------------------ ------ ---------- --------/vmfs/volumes/52b021c3-.../vmkdump/test.dumpfile True
True
104857600
What to do next
For information about other commands you can use to manage the core dump files, see the vSphere
Command-Line Interface Reference documentation.
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Deactivate and Delete a Core Dump File
Deactivate a configured core dump file and, if needed, remove it from the VMFS datastore.
You can temporarily deactivate the core dump file. If you do not plan to use the deactivated file, you can
remove it from the VMFS datastore. To remove the file that has not been deactivated, you can use the system
coredump file remove with the --force | -F option.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Deactivate the core dump file by running the following command:
esxcli system coredump file set --unconfigure | -u
2
Remove the file from the VMFS datastore:
system coredump file remove --file | -f file_name
The command takes the following options:
Option
Description
--file | -f
Specify the file name of the dump file to be removed. If you do not specify
the file name, the configured core dump file will be removed.
--force | -F
Deactivate and unconfigure the dump file being removed. This option is
required if the file has not been previously deactivated and is active.
The core dump file becomes disabled and is removed from the VMFS datastore.
Checking Metadata Consistency with VOMA
Use vSphere On-disk Metadata Analyzer (VOMA) to identify incidents of metadata corruption that affect
file systems or underlying logical volumes.
Problem
You can check metadata consistency when you experience problems with a VMFS datastore or a virtual flash
resource. For example, perform a metadata check if one of the following occurs:
n
You experience storage outages.
n
After you rebuild RAID or perform a disk replacement.
n
You see metadata errors in the vmkernel.log file similar to the following:
cpu11:268057)WARNING: HBX: 599: Volume 50fd60a3-3aae1ae2-3347-0017a4770402
("<Datastore_name>") may be damaged on disk. Corrupt heartbeat detected at offset 3305472:
[HB state 0 offset 6052837899185946624 gen 15439450 stampUS 5 $
n
You are unable to access files on a VMFS.
n
You see corruption being reported for a datastore in events tabs of vCenter Server.
Solution
To check metadata consistency, run VOMA from the CLI of an ESXi host. VOMA can be used to check and
fix minor inconsistency issues for a VMFS datastore or a virtual flash resource. To resolve errors reported by
VOMA, consult VMware Support.
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Follow these guidelines when you use the VOMA tool:
n
Make sure that the VMFS datastore you analyze does not span multiple extents. You can run VOMA
only against a single-extent datastore.
n
Power off any virtual machines that are running or migrate them to a different datastore.
The following example demonstrates how to use VOMA to check VMFS metadata consistency.
1
Obtain the name and partition number of the device that backs the VMFS datastore that you want to
check.
#esxcli storage vmfs extent list
The Device Name and Partition columns in the output identify the device. For example:
Volume Name
1TB_VMFS5
2
XXXXXXXX
XXXXXXXX
Device Name
naa.00000000000000000000000000000703
Partition
3
Check for VMFS errors.
Provide the absolute path to the device partition that backs the VMFS datastore, and provide a partition
number with the device name. For example:
# voma -m vmfs -f check -d /vmfs/devices/disks/naa.00000000000000000000000000000703:3
The output lists possible errors. For example, the following output indicates that the heartbeat address
is invalid.
XXXXXXXXXXXXXXXXXXXXXXX
Phase 2: Checking VMFS heartbeat region
ON-DISK ERROR: Invalid HB address
Phase 3: Checking all file descriptors.
Phase 4: Checking pathname and connectivity.
Phase 5: Checking resource reference counts.
Total Errors Found:
1
Command options that the VOMA tool takes include the following.
Table 16‑7. VOMA Command Options
Command Option
Description
-m | --module
The modules to run include the following:
-f | --func
-d | --device
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vmfs
If you do not specify the name of the module, this
option is used by default.
You can check VMFS3, VMFS5, and VMFS6 file
systems, as well as file systems that back virtual
flash resources. If you specify this module,
minimal checks are performed for LVM as well.
lvm
Check logical volumes that back VMFS datastores.
ptck
Check and validate VMFS partitions, such as MBR
or GPT. If no partition exists, determine whether
partitions should exist.
Functions to be performed include the following:
query
List functions supported by module.
check
Check for errors.
Device or disk to be inspected. Make sure to provide the absolute path to the device
partition backing the VMFS datastore. For example, /vmfs/devices/disks/naa.
00000000000000000000000000:1.
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Table 16‑7. VOMA Command Options (Continued)
Command Option
Description
-s | --logfile
Specify the log file to output the results.
-v | --version
Display the version of VOMA.
-h | --help
Display the help message for the VOMA command.
For more details, see the VMware Knowledge Base article 2036767.
Configuring VMFS Pointer Block Cache
You can use advanced VMFS parameters to configure the pointer block cache.
As the size of the virtual machine files on the VMFS datastores increases, the number of pointer blocks used
by those files also increases. The pointer blocks are used to address file blocks in the large virtual machine
files and virtual disks on the VMFS datastore.
You can configure the minimum and maximum sizes of the pointer block cache on each ESXi host. When the
size of the pointer block cache approaches the configured maximum size, an eviction mechanism removes
some pointer block entries from the cache.
Base the maximum size of the pointer block cache on the working size of all open virtual disk files that
reside on VMFS datastores. All VMFS datastores on the host use a single pointer block cache.
The minimum value is based on the minimum guaranteed memory that the system can allocate to the cache.
1 TB of open file space requires approximately 4 MB of memory.
To configure the minimum and maximum values for the pointer block cache, use the Advanced System
Settings dialog box of the vSphere Web Client
Table 16‑8. Advanced Parameters to Regulate Pointer Block Cache
Parameter
Values
Description
VMFS3.MaxAddressableSpaceTB
Default value is 32 (in TB).
Maximum size of all open files that
VMFS cache supports before eviction
starts.
VMFS3.MinAddressableSpaceTB
Default value is 10 (in TB).
Minimum size of all open files that
VMFS cache guarantees to support.
You can use the esxcli storage vmfs pbcache command to obtain information about the size of the pointer
block cache and other statistics. This information assists you in adjusting minimum and maximum sizes of
the pointer block cache, so that you can get maximum performance.
Set Advanced Host Attributes
You can set advanced attributes for a host.
Caution Changing advanced options is considered unsupported unless VMware technical support or a KB
article instruct you to do so. In all other cases, changing these options is considered unsupported. In most
cases, the default settings produce the optimum result.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
In Advanced System Settings, select the appropriate item.
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5
Click the Edit button to edit the value.
6
Click OK.
Obtain Information for VMFS Pointer Block Cache
You can get information about VMFS pointer block cache usage. This information helps you understand
how much space the pointer block cache consumes. You can also determine whether you must adjust the
minimum and maximum sizes of the pointer block cache.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To obtain or reset the pointer block cache statistics, use the following command:
esxcli storage vmfs pbcache
Option
Description
get
Get VMFS pointer block cache statistics.
reset
Reset the VMFS pointer block cache statistics.
Example: Getting Statistics for Pointer Block Cache
#esxcli storage vmfs pbcache get
Cache Capacity Miss Ratio: 0 %
Cache Size: 0 MiB
Cache Size Max: 132 MiB
Cache Usage: 0 %
Cache Working Set: 0 TiB
Cache Working Set Max: 32 TiB
Vmfs Heap Overhead: 0 KiB
Vmfs Heap Size: 23 MiB
Vmfs Heap Size Max: 256 MiB
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Understanding Multipathing and
Failover
17
To maintain a constant connection between a host and its storage, ESXi supports multipathing. Multipathing
is a technique that lets you use more than one physical path that transfers data between the host and an
external storage device.
In case of a failure of any element in the SAN network, such as an adapter, switch, or cable, ESXi can switch
to another physical path, which does not use the failed component. This process of path switching to avoid
failed components is known as path failover.
In addition to path failover, multipathing provides load balancing. Load balancing is the process of
distributing I/O loads across multiple physical paths. Load balancing reduces or removes potential
bottlenecks.
Note Virtual machine I/O might be delayed for up to sixty seconds while path failover takes place. These
delays allow the SAN to stabilize its configuration after topology changes. In general, the I/O delays might
be longer on active-passive arrays and shorter on active-active arrays.
This chapter includes the following topics:
n
“Failover with Fibre Channel,” on page 181
n
“Host-Based Failover with iSCSI,” on page 182
n
“Array-Based Failover with iSCSI,” on page 184
n
“Path Failover and Virtual Machines,” on page 185
n
“Managing Multiple Paths,” on page 186
n
“VMware Multipathing Module,” on page 187
n
“Path Scanning and Claiming,” on page 189
n
“Managing Storage Paths and Multipathing Plug-Ins,” on page 192
n
“Scheduling Queues for Virtual Machine I/Os,” on page 200
Failover with Fibre Channel
To support multipathing, your host typically has two or more HBAs available. This configuration
supplements the SAN multipathing configuration that generally provides one or more switches in the SAN
fabric and one or more storage processors on the storage array device itself.
In the following illustration, multiple physical paths connect each server with the storage device. For
example, if HBA1 or the link between HBA1 and the FC switch fails, HBA2 takes over and provides the
connection between the server and the switch. The process of one HBA taking over for another is called
HBA failover.
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Figure 17‑1. Multipathing and Failover with Fibre Channel
Host 2
Host 1
HBA2
HBA1
HBA3
HBA4
switch
switch
SP1
SP2
storage array
Similarly, if SP1 fails or the links between SP1 and the switches breaks, SP2 takes over and provides the
connection between the switch and the storage device. This process is called SP failover. VMware ESXi
supports both HBA and SP failovers with its multipathing capability.
Host-Based Failover with iSCSI
When setting up your ESXi host for multipathing and failover, you can use multiple iSCSI HBAs or multiple
NICs depending on the type of iSCSI adapters on your host.
For information on different types of iSCSI adapters, see “iSCSI Initiators,” on page 65.
When you use multipathing, specific considerations apply.
n
ESXi does not support multipathing when you combine an independent hardware adapter with
software iSCSI or dependent iSCSI adapters in the same host.
n
Multipathing between software and dependent adapters within the same host is supported.
n
On different hosts, you can mix both dependent and independent adapters.
The following illustration shows multipathing setups possible with different types of iSCSI initiators.
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Figure 17‑2. Host-Based Path Failover
hardware
iSCSI
software
iSCSI
host 1
host 2
software
adapter
HBA2
HBA1
NIC2
NIC1
IP network
SP
iSCSI storage
Failover with Hardware iSCSI
With hardware iSCSI, the host typically has two or more hardware iSCSI adapters available, from which the
storage system can be reached using one or more switches. Alternatively, the setup might include one
adapter and two storage processors so that the adapter can use a different path to reach the storage system.
On the Host-Based Path Failover illustration, Host1 has two hardware iSCSI adapters, HBA1 and HBA2, that
provide two physical paths to the storage system. Multipathing plug-ins on your host, whether the
VMkernel NMP or any third-party MPPs, have access to the paths by default and can monitor health of each
physical path. If, for example, HBA1 or the link between HBA1 and the network fails, the multipathing
plug-ins can switch the path over to HBA2.
Failover with Software iSCSI
With software iSCSI, as shown on Host 2 of the Host-Based Path Failover illustration, you can use multiple
NICs that provide failover and load balancing capabilities for iSCSI connections between your host and
storage systems.
For this setup, because multipathing plug-ins do not have direct access to physical NICs on your host, you
first need to connect each physical NIC to a separate VMkernel port. You then associate all VMkernel ports
with the software iSCSI initiator using a port binding technique. As a result, each VMkernel port connected
to a separate NIC becomes a different path that the iSCSI storage stack and its storage-aware multipathing
plug-ins can use.
For information on how to configure multipathing for software iSCSI, see “Setting Up iSCSI Network,” on
page 81.
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Array-Based Failover with iSCSI
Some iSCSI storage systems manage path use of their ports automatically and transparently to ESXi.
When using one of these storage systems, your host does not see multiple ports on the storage and cannot
choose the storage port it connects to. These systems have a single virtual port address that your host uses to
initially communicate. During this initial communication, the storage system can redirect the host to
communicate with another port on the storage system. The iSCSI initiators in the host obey this reconnection
request and connect with a different port on the system. The storage system uses this technique to spread
the load across available ports.
If the ESXi host loses connection to one of these ports, it automatically attempts to reconnect with the virtual
port of the storage system, and should be redirected to an active, usable port. This reconnection and
redirection happens quickly and generally does not disrupt running virtual machines. These storage
systems can also request that iSCSI initiators reconnect to the system, to change which storage port they are
connected to. This allows the most effective use of the multiple ports.
The Port Redirection illustration shows an example of port redirection. The host attempts to connect to the
10.0.0.1 virtual port. The storage system redirects this request to 10.0.0.2. The host connects with 10.0.0.2 and
uses this port for I/O communication.
Note The storage system does not always redirect connections. The port at 10.0.0.1 could be used for
traffic, also.
Figure 17‑3. Port Redirection
“Connect to storage at 10.0.0.1”
Host 1
10.0.0.1
“Reconnect to 10.0.0.2”
10.0.0.2
storage
iSCSI storage traffic
Host 2
10.0.0.1
10.0.0.2
storage
If the port on the storage system that is acting as the virtual port becomes unavailable, the storage system
reassigns the address of the virtual port to another port on the system. Port Reassignment shows an example
of this type of port reassignment. In this case, the virtual port 10.0.0.1 becomes unavailable and the storage
system reassigns the virtual port IP address to a different port. The second port responds to both addresses.
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Figure 17‑4. Port Reassignment
10.0.0.1
10.0.0.2
storage
10.0.0.1
10.0.0.1
10.0.0.2
storage
With this form of array-based failover, you can have multiple paths to the storage only if you use multiple
ports on the ESXi host. These paths are active-active. For additional information, see “iSCSI Session
Management,” on page 99.
Path Failover and Virtual Machines
Path failover occurs when the active path to a LUN is changed from one path to another, usually because of
a SAN component failure along the current path.
When a path fails, storage I/O might pause for 30 to 60 seconds until your host determines that the link is
unavailable and completes failover. If you attempt to display the host, its storage devices, or its adapters, the
operation might appear to stall. Virtual machines with their disks installed on the SAN can appear
unresponsive. After failover is complete, I/O resumes normally and the virtual machines continue to run.
However, when failovers take a long time to complete, a Windows virtual machine might interrupt the I/O
and eventually fail. To avoid the failure, set the disk timeout value for the Windows virtual machine to at
least 60 seconds.
Set Timeout on Windows Guest OS
Increase the standard disk timeout value on a Windows guest operating system to avoid disruptions during
a path failover.
This procedure explains how to change the timeout value by using the Windows registry.
Prerequisites
Back up the Windows registry.
Procedure
1
Select Start > Run.
2
Type regedit.exe, and click OK.
3
In the left-panel hierarchy view, double-click HKEY_LOCAL_MACHINE > System >
CurrentControlSet > Services > Disk.
4
Double-click TimeOutValue.
5
Set the value data to 0x3c (hexadecimal) or 60 (decimal) and click OK.
After you make this change, Windows waits at least 60 seconds for delayed disk operations to complete
before it generates errors.
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6
Reboot guest OS for the change to take effect.
Managing Multiple Paths
To manage storage multipathing, ESXi uses a collection of Storage APIs, also called the Pluggable Storage
Architecture (PSA). The PSA is an open, modular framework that coordinates the simultaneous operation of
multiple multipathing plug-ins (MPPs). The PSA allows 3rd party software developers to design their own
load balancing techniques and failover mechanisms for particular storage array, and insert their code
directly into the ESXi storage I/O path.
Topics discussing path management use the following acronyms.
Table 17‑1. Multipathing Acronyms
Acronym
Definition
PSA
Pluggable Storage Architecture
NMP
Native Multipathing Plug-In. Generic VMware
multipathing module.
PSP
Path Selection Plug-In, also called Path Selection Policy.
Handles path selection for a given device.
SATP
Storage Array Type Plug-In, also called Storage Array Type
Policy. Handles path failover for a given storage array.
The VMkernel multipathing plug-in that ESXi provides by default is the VMware Native Multipathing PlugIn (NMP). The NMP is an extensible module that manages sub plug-ins. There are two types of NMP sub
plug-ins, Storage Array Type Plug-Ins (SATPs), and Path Selection Plug-Ins (PSPs). SATPs and PSPs can be
built-in and provided by VMware, or can be provided by a third party.
If more multipathing functionality is required, a third party can also provide an MPP to run in addition to,
or as a replacement for, the default NMP.
When coordinating the VMware NMP and any installed third-party MPPs, the PSA performs the following
tasks:
n
Loads and unloads multipathing plug-ins.
n
Hides virtual machine specifics from a particular plug-in.
n
Routes I/O requests for a specific logical device to the MPP managing that device.
n
Handles I/O queueing to the logical devices.
n
Implements logical device bandwidth sharing between virtual machines.
n
Handles I/O queueing to the physical storage HBAs.
n
Handles physical path discovery and removal.
n
Provides logical device and physical path I/O statistics.
As the Pluggable Storage Architecture illustration shows, multiple third-party MPPs can run in parallel with
the VMware NMP. When installed, the third-party MPPs replace the behavior of the NMP and take
complete control of the path failover and the load-balancing operations for specified storage devices.
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Figure 17‑5. Pluggable Storage Architecture
VMkernel
pluggable storage architecture
third-party
MPP
third-party
MPP
VMware NMP
VMware SATP
VMware PSP
VMware SATP
VMware PSP
VMware SATP
third-party SATP
third-party PSP
The multipathing modules perform the following operations:
n
Manage physical path claiming and unclaiming.
n
Manage creation, registration, and deregistration of logical devices.
n
Associate physical paths with logical devices.
n
Support path failure detection and remediation.
n
Process I/O requests to logical devices:
n
n
Select an optimal physical path for the request.
n
Depending on a storage device, perform specific actions necessary to handle path failures and I/O
command retries.
Support management tasks, such as reset of logical devices.
VMware Multipathing Module
By default, ESXi provides an extensible multipathing module called the Native Multipathing Plug-In
(NMP).
Generally, the VMware NMP supports all storage arrays listed on the VMware storage HCL and provides a
default path selection algorithm based on the array type. The NMP associates a set of physical paths with a
specific storage device, or LUN. The specific details of handling path failover for a given storage array are
delegated to a Storage Array Type Plug-In (SATP). The specific details for determining which physical path
is used to issue an I/O request to a storage device are handled by a Path Selection Plug-In (PSP). SATPs and
PSPs are sub plug-ins within the NMP module.
With ESXi, the appropriate SATP for an array you use will be installed automatically. You do not need to
obtain or download any SATPs.
VMware SATPs
Storage Array Type Plug-Ins (SATPs) run in conjunction with the VMware NMP and are responsible for
array-specific operations.
ESXi offers a SATP for every type of array that VMware supports. It also provides default SATPs that
support non-specific active-active and ALUA storage arrays, and the local SATP for direct-attached devices.
Each SATP accommodates special characteristics of a certain class of storage arrays and can perform the
array-specific operations required to detect path state and to activate an inactive path. As a result, the NMP
module itself can work with multiple storage arrays without having to be aware of the storage device
specifics.
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After the NMP determines which SATP to use for a specific storage device and associates the SATP with the
physical paths for that storage device, the SATP implements the tasks that include the following:
n
Monitors the health of each physical path.
n
Reports changes in the state of each physical path.
n
Performs array-specific actions necessary for storage fail-over. For example, for active-passive devices, it
can activate passive paths.
VMware PSPs
Path Selection Plug-Ins (PSPs) are sub plug-ins of the VMware NMP and are responsible for choosing a
physical path for I/O requests.
The VMware NMP assigns a default PSP for each logical device based on the SATP associated with the
physical paths for that device. You can override the default PSP. For information, see “Path Scanning and
Claiming,” on page 189.
By default, the VMware NMP supports the following PSPs:
VMW_PSP_MRU
The host selects the path that it used most recently. When the path becomes
unavailable, the host selects an alternative path. The host does not revert to
the original path when that path becomes available again. There is no
preferred path setting with the MRU policy. MRU is the default policy for
most active-passive storage devices.
The VMW_PSP_MRU ranking capability allows you to assign ranks to
individual paths. To set ranks to individual paths, use the esxcli storage
nmp psp generic pathconfig set command. For details, see the VMware
knowledge base article at http://kb.vmware.com/kb/2003468.
The policy is displayed in the client as the Most Recently Used (VMware)
path selection policy.
VMW_PSP_FIXED
The host uses the designated preferred path, if it has been configured.
Otherwise, it selects the first working path discovered at system boot time. If
you want the host to use a particular preferred path, specify it manually.
Fixed is the default policy for most active-active storage devices.
Note If the host uses a default preferred path and the path's status turns to
Dead, a new path is selected as preferred. However, if you explicitly
designate the preferred path, it will remain preferred even when it becomes
inaccessible.
Displayed in the client as the Fixed (VMware) path selection policy.
VMW_PSP_RR
The host uses an automatic path selection algorithm rotating through all
active paths when connecting to active-passive arrays, or through all
available paths when connecting to active-active arrays. RR is the default for
a number of arrays and can be used with both active-active and activepassive arrays to implement load balancing across paths for different LUNs.
Displayed in the client as the Round Robin (VMware) path selection policy.
VMware NMP Flow of I/O
When a virtual machine issues an I/O request to a storage device managed by the NMP, the following
process takes place.
1
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The NMP calls the PSP assigned to this storage device.
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Chapter 17 Understanding Multipathing and Failover
2
The PSP selects an appropriate physical path on which to issue the I/O.
3
The NMP issues the I/O request on the path selected by the PSP.
4
If the I/O operation is successful, the NMP reports its completion.
5
If the I/O operation reports an error, the NMP calls the appropriate SATP.
6
The SATP interprets the I/O command errors and, when appropriate, activates the inactive paths.
7
The PSP is called to select a new path on which to issue the I/O.
Path Scanning and Claiming
When you start your ESXi host or rescan your storage adapter, the host discovers all physical paths to
storage devices available to the host. Based on a set of claim rules, the host determines which multipathing
plug-in (MPP) should claim the paths to a particular device and become responsible for managing the
multipathing support for the device.
By default, the host performs a periodic path evaluation every 5 minutes causing any unclaimed paths to be
claimed by the appropriate MPP.
The claim rules are numbered. For each physical path, the host runs through the claim rules starting with
the lowest number first. The attributes of the physical path are compared to the path specification in the
claim rule. If there is a match, the host assigns the MPP specified in the claim rule to manage the physical
path. This continues until all physical paths are claimed by corresponding MPPs, either third-party
multipathing plug-ins or the native multipathing plug-in (NMP).
For the paths managed by the NMP module, a second set of claim rules is applied. These rules determine
which Storage Array Type Plug-In (SATP) should be used to manage the paths for a specific array type, and
which Path Selection Plug-In (PSP) is to be used for each storage device.
Use the vSphere Web Client to view which SATP and PSP the host is using for a specific storage device and
the status of all available paths for this storage device. If needed, you can change the default VMware PSP
using the client. To change the default SATP, you need to modify claim rules using the vSphere CLI.
You can find some information about modifying claim rules in “Managing Storage Paths and Multipathing
Plug-Ins,” on page 192.
For more information about the commands available to manage PSA, see Getting Started with vSphere
Command-Line Interfaces.
For a complete list of storage arrays and corresponding SATPs and PSPs, see the SAN Array Model
Reference section of the vSphere Compatibility Guide.
Viewing the Paths Information
You can review the storage array type policy (SATP) and path selection policy (PSP) that the ESXi host uses
for a specific storage device and the status of all available paths for this storage device. You can access the
path information from both the Datastores and Devices views. For datastores, you review the paths that
connect to the device the datastore is deployed on.
The path information includes the SATP assigned to manage the device, the PSP, a list of paths, and the
status of each path. The following path status information can appear:
Active
Paths available for issuing I/O to a LUN. A single or multiple working paths
currently used for transferring data are marked as Active (I/O).
Standby
If active paths fail, the path can quickly become operational and can be used
for I/O.
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Disabled
The path is disabled and no data can be transferred.
Dead
The software cannot connect to the disk through this path.
If you are using the Fixed path policy, you can see which path is the preferred path. The preferred path is
marked with an asterisk (*) in the Preferred column.
For each path you can also display the path's name. The name includes parameters that describe the path:
adapter ID, target ID, and device ID. Usually, the path's name has the format similar to the following:
fc.adapterID-fc.targetID-naa.deviceID
Note When you use the host profiles editor to edit paths, you must specify all three parameters that
describe a path, adapter ID, target ID, and device ID.
View Datastore Paths
Review the paths that connect to storage devices backing your datastores.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the datastore to display its information.
3
Click the Configure tab.
4
Click Connectivity and Multipathing.
5
If the datastore is shared, select a host to view multipathing details for its devices.
6
Under Multipathing Details, review the multipathing policies and paths for the storage device that
backs your datastore.
View Storage Device Paths
View which multipathing policies the host uses for a specific storage device and the status of all available
paths for this storage device.
Procedure
190
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
Select the storage device whose paths you want to view.
5
Click the Properties tab and review details under Multipathing Policies.
6
Click the Paths tab to review all paths available for the storage device.
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Chapter 17 Understanding Multipathing and Failover
Setting a Path Selection Policy
For each storage device, the ESXi host sets the path selection policy based on the claim rules.
By default, VMware supports the following path selection policies. If you have a third-party PSP installed
on your host, its policy also appears on the list.
Fixed (VMware)
The host uses the designated preferred path, if it has been configured.
Otherwise, it selects the first working path discovered at system boot time. If
you want the host to use a particular preferred path, specify it manually.
Fixed is the default policy for most active-active storage devices.
Note If the host uses a default preferred path and the path's status turns to
Dead, a new path is selected as preferred. However, if you explicitly
designate the preferred path, it will remain preferred even when it becomes
inaccessible.
Most Recently Used
(VMware)
The host selects the path that it used most recently. When the path becomes
unavailable, the host selects an alternative path. The host does not revert to
the original path when that path becomes available again. There is no
preferred path setting with the MRU policy. MRU is the default policy for
most active-passive storage devices.
Round Robin (VMware)
The host uses an automatic path selection algorithm rotating through all
active paths when connecting to active-passive arrays, or through all
available paths when connecting to active-active arrays. RR is the default for
a number of arrays and can be used with both active-active and activepassive arrays to implement load balancing across paths for different LUNs.
Change the Path Selection Policy
Generally, you do not need to change the default multipathing settings your host uses for a specific storage
device. However, if you want to make any changes, you can use the Edit Multipathing Policies dialog box to
modify a path selection policy and specify the preferred path for the Fixed policy. You can also use this
dialog box to change multipathing for SCSI-based protocol endpoints.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices or Protocol Endpoints.
4
Select the item whose paths you want to change and click the Properties tab.
5
Under Multipathing Policies, click Edit Multipathing.
6
Select a path policy.
By default, VMware supports the following path selection policies. If you have a third-party PSP
installed on your host, its policy also appears on the list.
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n
Fixed (VMware)
n
Most Recently Used (VMware)
n
Round Robin (VMware)
For the fixed policy, specify the preferred path.
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8
Click OK to save your settings and exit the dialog box.
Disable Storage Paths
You can temporarily disable paths for maintenance or other reasons.
You disable a path using the Paths panel. You have several ways to access the Paths panel, from a datastore,
a storage device, or an adapter view. This task explains how to disable a path using a storage device view.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Storage Devices.
4
Select the storage device whose paths you want to disable and click the Paths tab.
5
Select the path to disable and click Disable.
Managing Storage Paths and Multipathing Plug-Ins
Use the esxcli commands to manage the PSA multipathing plug-ins and storage paths assigned to them.
You can display all multipathing plug-ins available on your host. You can list any third-party MPPs, as well
as your host's NMP and SATPs and review the paths they claim. You can also define new paths and specify
which multipathing plug-in should claim the paths.
For more information about commands available to manage PSA, see the Getting Started with vSphere
Command-Line Interfaces.
Multipathing Considerations
Specific considerations apply when you manage storage multipathing plug-ins and claim rules.
The following considerations help you with multipathing:
192
n
If no SATP is assigned to the device by the claim rules, the default SATP for iSCSI or FC devices is
VMW_SATP_DEFAULT_AA. The default PSP is VMW_PSP_FIXED.
n
When the system searches the SATP rules to locate a SATP for a given device, it searches the driver
rules first. If there is no match, the vendor/model rules are searched, and finally the transport rules are
searched. If no match occurs, NMP selects a default SATP for the device.
n
If VMW_SATP_ALUA is assigned to a specific storage device, but the device is not ALUA-aware, no
claim rule match occurs for this device. The device is claimed by the default SATP based on the device's
transport type.
n
The default PSP for all devices claimed by VMW_SATP_ALUA is VMW_PSP_MRU. The
VMW_PSP_MRU selects an active/optimized path as reported by the VMW_SATP_ALUA, or an
active/unoptimized path if there is no active/optimized path. This path is used until a better path is
available (MRU). For example, if the VMW_PSP_MRU is currently using an active/unoptimized path
and an active/optimized path becomes available, the VMW_PSP_MRU will switch the current path to
the active/optimized one.
n
While VMW_PSP_MRU is typically selected for ALUA arrays by default, certain ALUA storage arrays
need to use VMW_PSP_FIXED. To check whether your storage array requires VMW_PSP_FIXED, see
the VMware Compatibility Guide or contact your storage vendor. When using VMW_PSP_FIXED with
ALUA arrays, unless you explicitly specify a preferred path, the ESXi host selects the most optimal
working path and designates it as the default preferred path. If the host selected path becomes
unavailable, the host selects an alternative available path. However, if you explicitly designate the
preferred path, it will remain preferred no matter what its status is.
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Chapter 17 Understanding Multipathing and Failover
n
By default, the PSA claim rule 101 masks Dell array pseudo devices. Do not delete this rule, unless you
want to unmask these devices.
List Multipathing Claim Rules for the Host
Use the esxcli command to list available multipathing claim rules.
Claim rules indicate which multipathing plug-in, the NMP or any third-party MPP, manages a given
physical path. Each claim rule identifies a set of paths based on the following parameters:
n
Vendor/model strings
n
Transportation, such as SATA, IDE, Fibre Channel, and so on
n
Adapter, target, or LUN location
n
Device driver, for example, Mega-RAID
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
Run the esxcli --server=server_name storage core claimrule list --claimrule-class=MP command
to list the multipathing claim rules.
Example: Sample Output of the esxcli storage core claimrule list Command
Rule Class
MP
MP
MP
MP
MP
MP
MP
MP
MP
MP
MP
MP
MP
Rule
0
1
2
3
4
101
101
200
200
201
201
202
202
Class
runtime
runtime
runtime
runtime
runtime
runtime
file
runtime
file
runtime
file
runtime
file
Type
transport
transport
transport
transport
transport
vendor
vendor
vendor
vendor
location
location
driver
driver
Plugin
NMP
NMP
NMP
NMP
NMP
MASK_PATH
MASK_PATH
MPP_1
MPP_1
MPP_2
MPP_2
MPP_3
MPP_3
Matches
transport=usb
transport=sata
transport=ide
transport=block
transport=unknown
vendor=DELL model=Universal Xport
vendor=DELL model=Universal Xport
vendor=NewVend model=*
vendor=NewVend model=*
adapter=vmhba41 channel=* target=* lun=*
adapter=vmhba41 channel=* target=* lun=*
driver=megaraid
driver=megaraid
MP
65535
runtime
vendor
NMP
vendor=* model=*
This example indicates the following:
n
The NMP claims all paths connected to storage devices that use the USB, SATA, IDE, and Block SCSI
transportation.
n
You can use the MASK_PATH module to hide unused devices from your host. By default, the PSA
claim rule 101 masks Dell array pseudo devices with a vendor string of DELL and a model string of
Universal Xport.
n
The MPP_1 module claims all paths connected to any model of the NewVend storage array.
n
The MPP_3 module claims the paths to storage devices controlled by the Mega-RAID device driver.
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n
Any paths not described in the previous rules are claimed by NMP.
n
The Rule Class column in the output describes the category of a claim rule. It can be MP (multipathing
plug-in), Filter, or VAAI.
n
The Class column shows which rules are defined and which are loaded. The file parameter in the Class
column indicates that the rule is defined. The runtime parameter indicates that the rule has been loaded
into your system. For a user-defined claim rule to be active, two lines with the same rule number should
exist, one line for the rule with the file parameter and another line with runtime. Several low
numbered rules, have only one line with the Class of runtime. These are system-defined claim rules that
you cannot modify.
Display Multipathing Modules
Use the esxcli command to list all multipathing modules loaded into the system. Multipathing modules
manage physical paths that connect your host with storage.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To list multipathing modules, run the following command:
esxcli --server=server_name storage core plugin list --plugin-class=MP
This command typically shows the NMP and, if loaded, the MASK_PATH module. If any third-party MPPs
have been loaded, they are listed as well.
Display SATPs for the Host
Use the esxcli command to list VMware NMP SATPs loaded into the system. Display information about the
SATPs.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To list VMware SATPs, run the following command:
esxcli --server=server_name storage nmp satp list
For each SATP, the output displays information that shows the type of storage array or system this SATP
supports and the default PSP for any LUNs using this SATP. Placeholder (plugin not loaded) in the
Description column indicates that the SATP is not loaded.
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Display NMP Storage Devices
Use the esxcli command to list all storage devices controlled by the VMware NMP and display SATP and
PSP information associated with each device.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To list all storage devices, run the following command:
esxcli --server=server_name storage nmp device list
Use the --device | -d=device_ID option to filter the output of this command to show a single device.
Add Multipathing Claim Rules
Use the esxcli commands to add a new multipathing PSA claim rule to the set of claim rules on the system.
For the new claim rule to be active, you first define the rule and then load it into your system.
You add a new PSA claim rule when, for example, you load a new multipathing plug-in (MPP) and need to
define which paths this module should claim. You may need to create a claim rule if you add new paths and
want an existing MPP to claim them.
Caution When creating new claim rules, be careful to avoid a situation where different physical paths to
the same LUN are claimed by different MPPs. Unless one of the MPPs is the MASK_PATH MPP, this
configuration will cause performance problems.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
To define a new claim rule, run the following command:
esxcli --server=server_name storage core claimrule add
The command takes the following options:
VMware, Inc.
Option
Description
-A|--adapter=<str>
Indicate the adapter of the paths to use in this operation.
-u|--autoassign
The system will auto assign a rule ID.
-C|--channel=<long>
Indicate the channel of the paths to use in this operation.
-c|--claimrule-class=<str>
Indicate the claim rule class to use in this operation.
Valid values are: MP, Filter, VAAI.
-d|--device=<str>
Indicate the device Uid to use for this operation.
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2
Option
Description
-D|--driver=<str>
Indicate the driver of the paths to use in this operation.
-f|--force
Force claim rules to ignore validity checks and install the rule anyway.
--if-unset=<str>
Execute this command if this advanced user variable is not set to 1.
-i|--iqn=<str>
Indicate the iSCSI Qualified Name for the target to use in this operation.
-L|--lun=<long>
Indicate the LUN of the paths to use in this operation.
-M|--model=<str>
Indicate the model of the paths to use in this operation.
-P|--plugin=<str>
Indicate which PSA plugin to use for this operation. (required)
-r|--rule=<long>
Indicate the rule ID to use for this operation.
-T|--target=<long>
Indicate the target of the paths to use in this operation.
-R|--transport=<str>
Indicate the transport of the paths to use in this operation.
Valid values are: block, fc, iscsi, iscsivendor, ide, sas, sata, usb, parallel,
unknown.
-t|--type=<str>
Indicate which type of matching is used for claim/unclaim or claimrule.
Valid values are: vendor, location, driver, transport, device, target.
(required)
-V|--vendor=<str>
Indicate the vendor of the paths to user in this operation.
--wwnn=<str>
Indicate the World-Wide Node Number for the target to use in this
operation.
--wwpn=<str>
Indicate the World-Wide Port Number for the target to use in this
operation.
To load the new claim rule into your system, run the following command:
esxcli --server=server_name storage core claimrule load
This command loads all newly created multipathing claim rules from your system's configuration file.
Example: Defining Multipathing Claim Rules
In the following example, you add and load rule # 500 to claim all paths with the NewMod model string and
the NewVend vendor string for the NMP plug-in.
# esxcli --server=server_name storage core claimrule add -r 500 -t vendor -V NewVend -M NewMod -P
NMP
# esxcli --server=server_name storage core claimrule load
After you run the esxcli --server=server_name storage core claimrule list command, you can see the
new claim rule appearing on the list.
Note The two lines for the claim rule, one with the Class of runtime and another with the Class of file,
indicate that the new claim rule has been loaded into the system and is active.
Rule Class
MP
MP
MP
MP
MP
MP
MP
MP
MP
196
Rule
0
1
2
3
4
101
101
500
500
Class
runtime
runtime
runtime
runtime
runtime
runtime
file
runtime
file
Type
transport
transport
transport
transport
transport
vendor
vendor
vendor
vendor
Plugin
NMP
NMP
NMP
NMP
NMP
MASK_PATH
MASK_PATH
NMP
NMP
Matches
transport=usb
transport=sata
transport=ide
transport=block
transport=unknown
vendor=DELL model=Universal Xport
vendor=DELL model=Universal Xport
vendor=NewVend model=NewMod
vendor=NewVend model=NewMod
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Chapter 17 Understanding Multipathing and Failover
Delete Multipathing Claim Rules
Use the esxcli commands to remove a multipathing PSA claim rule from the set of claim rules on the
system.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Delete a claim rule from the set of claim rules.
esxcli --server=server_name storage core claimrule remove
Note By default, the PSA claim rule 101 masks Dell array pseudo devices. Do not delete this rule,
unless you want to unmask these devices.
The command takes the following options:
Option
Description
-c|--claimrule-class=<str>
Indicate the claim rule class to use in this operation (MP, Filter, VAAI).
-P|--plugin=<str>
Indicate the plugin to use for this operation.
-r|--rule=<long>
Indicate the rule ID to use for this operation.
This step removes the claim rule from the File class.
2
Remove the claim rule from the system.
esxcli --server=server_name storage core claimrule load
This step removes the claim rule from the Runtime class.
Mask Paths
You can prevent the host from accessing storage devices or LUNs or from using individual paths to a LUN.
Use the esxcli commands to mask the paths. When you mask paths, you create claim rules that assign the
MASK_PATH plug-in to the specified paths.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Check what the next available rule ID is.
esxcli --server=server_name storage core claimrule list
The claim rules that you use to mask paths should have rule IDs in the range of 101 – 200. If this
command shows that rule 101 and 102 already exist, you can specify 103 for the rule to add.
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2
Assign the MASK_PATH plug-in to a path by creating a new claim rule for the plug-in.
esxcli --server=server_name storage core claimrule add -P MASK_PATH
3
Load the MASK_PATH claim rule into your system.
esxcli --server=server_name storage core claimrule load
4
Verify that the MASK_PATH claim rule was added correctly.
esxcli --server=server_name storage core claimrule list
5
If a claim rule for the masked path exists, remove the rule.
esxcli --server=server_name storage core claiming unclaim
6
Run the path claiming rules.
esxcli --server=server_name storage core claimrule run
After you assign the MASK_PATH plug-in to a path, the path state becomes irrelevant and is no longer
maintained by the host. As a result, commands that display the masked path's information might show the
path state as dead.
Example: Masking a LUN
In this example, you mask the LUN 20 on targets T1 and T2 accessed through storage adapters vmhba2 and
vmhba3.
1
#esxcli --server=server_name storage core claimrule list
2
#esxcli --server=server_name
vmhba2 -C 0 -T 1 -L 20
#esxcli --server=server_name
vmhba3 -C 0 -T 1 -L 20
#esxcli --server=server_name
vmhba2 -C 0 -T 2 -L 20
#esxcli --server=server_name
vmhba3 -C 0 -T 2 -L 20
storage core claimrule add -P MASK_PATH -r 109 -t location -A
storage core claimrule add -P MASK_PATH -r 110 -t location -A
storage core claimrule add -P MASK_PATH -r 111 -t location -A
storage core claimrule add -P MASK_PATH -r 112 -t location -A
3
#esxcli --server=server_name storage core claimrule load
4
#esxcli --server=server_name storage core claimrule list
5
#esxcli --server=server_name storage core claiming unclaim -t location -A vmhba2
#esxcli --server=server_name storage core claiming unclaim -t location -A vmhba3
6
#esxcli --server=server_name storage core claimrule run
Unmask Paths
When you need the host to access the masked storage device, unmask the paths to the device.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Note When you run an unclaim operation using a device property, for example, device ID, vendor, or
model, the paths claimed by the MASK_PATH plugin are not unclaimed. The MASK_PATH plugin does not
keep track of any device property of the paths that it claims.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
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Procedure
1
Delete the MASK_PATH claim rule.
esxcli --server=server_name storage core claimrule remove -r rule#
2
Verify that the claim rule was deleted correctly.
esxcli --server=server_name storage core claimrule list
3
Reload the path claiming rules from the configuration file into the VMkernel.
esxcli --server=server_name storage core claimrule load
4
Run the esxcli --server=server_name storage core claiming unclaim command for each path to the
masked storage device.
For example:
esxcli --server=server_name storage core claiming unclaim -t location -A vmhba0 -C 0 -T 0 -L
149
5
Run the path claiming rules.
esxcli --server=server_name storage core claimrule run
Your host can now access the previously masked storage device.
Define NMP SATP Rules
The NMP SATP claim rules specify which SATP should manage a particular storage device. Usually you do
not need to modify the NMP SATP rules. If you need to do so, use the esxcli commands to add a rule to the
list of claim rules for the specified SATP.
You might need to create a SATP rule when you install a third-party SATP for a specific storage array.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
To add a claim rule for a specific SATP, run the
esxcli --server=server_name storage nmp satp rule add command. The command takes the
following options.
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Option
Description
-b|--boot
This is a system default rule added at boot time. Do not modify esx.conf or
add to host profile.
-c|--claim-option=string
Set the claim option string when adding a SATP claim rule.
-e|--description=string
Set the claim rule description when adding a SATP claim rule.
-d|--device=string
Set the device when adding SATP claim rules. Device rules are mutually
exclusive with vendor/model and driver rules.
-D|--driver=string
Set the driver string when adding a SATP claim rule. Driver rules are
mutually exclusive with vendor/model rules.
-f|--force
Force claim rules to ignore validity checks and install the rule anyway.
-h|--help
Show the help message.
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Option
Description
-M|--model=string
Set the model string when adding SATP a claim rule. Vendor/Model rules
are mutually exclusive with driver rules.
-o|--option=string
Set the option string when adding a SATP claim rule.
-P|--psp=string
Set the default PSP for the SATP claim rule.
-O|--psp-option=string
Set the PSP options for the SATP claim rule.
-s|--satp=string
The SATP for which a new rule will be added.
-R|--transport=string
Set the claim transport type string when adding a SATP claim rule.
-t|--type=string
Set the claim type when adding a SATP claim rule.
-V|--vendor=string
Set the vendor string when adding SATP claim rules. Vendor/Model rules
are mutually exclusive with driver rules.
Note When searching the SATP rules to locate a SATP for a given device, the NMP searches the driver
rules first. If there is no match, the vendor/model rules are searched, and finally the transport rules. If
there is still no match, NMP selects a default SATP for the device.
2
Reboot your host.
Example: Defining an NMP SATP Rule
The following sample command assigns the VMW_SATP_INV plug-in to manage storage arrays with
vendor string NewVend and model string NewMod.
# esxcli --server=server_name storage nmp satp rule add -V NewVend -M NewMod -s VMW_SATP_INV
If you run the esxcli --server=server_name storage nmp satp list -s VMW_SATP_INV command, you can
see the new rule added to the list of VMW_SATP_INV rules.
Scheduling Queues for Virtual Machine I/Os
By default, vSphere provides a mechanism that creates scheduling queues for every virtual machine file.
Each file, for example .vmdk, gets its own bandwidth controls.
This mechanism ensures that I/O for a particular virtual machine file, such as .vmdk, goes into its own
separate queue and does not interfere with I/Os from other files.
This capability is enabled by default. If you need to turn it off, you can do this by adjusting the
VMkernel.Boot.isPerFileSchedModelActive parameter in the advanced system settings.
Edit Per File I/O Scheduling
The advanced VMkernel.Boot.isPerFileSchedModelActive parameter controls the per file I/O scheduling
mechanism. The mechanism is enabled by default.
Procedure
200
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
Under Advanced System Settings, select the VMkernel.Boot.isPerFileSchedModelActive parameter
and click the Edit icon.
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5
Select one of the following options:
n
To disable the per file scheduling mechanism, change the value to No.
Note After you turn off the per file I/O scheduling model, your host reverts to a legacy
scheduling mechanism that uses a single I/O queue. The host maintains the single I/O queue for
each virtual machine and storage device pair. All I/Os between the virtual machine and its virtual
disks stored on the storage device are moved into this queue. As a result, I/Os from different
virtual disks might interfere with each other in sharing the bandwidth and affect each others
performance.
n
6
To reenable the per file scheduling mechanism, change the value to Yes.
Reboot the host for the changes to take effect.
Use esxcli Commands to Enable or Disable Per File I/O Scheduling
You can use the esxcli commands to change to I/O scheduling capability. The capability is enabled by
default.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
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To enable or disable per file I/O scheduling, run the following commands:
Option
Description
esxcli system settings kernel set -s
isPerFileSchedModelActive -v
FALSE
Disable per file I/O scheduling
esxcli system settings kernel set -s
isPerFileSchedModelActive -v TRUE
Enable per file I/O scheduling
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Raw Device Mapping
18
Raw device mapping (RDM) provides a mechanism for a virtual machine to have direct access to a LUN on
the physical storage subsystem.
The following topics contain information about RDMs and provide instructions on how to create and
manage RDMs.
This chapter includes the following topics:
n
“About Raw Device Mapping,” on page 203
n
“Raw Device Mapping Characteristics,” on page 206
n
“Create Virtual Machines with RDMs,” on page 208
n
“Manage Paths for a Mapped LUN,” on page 209
About Raw Device Mapping
An RDM is a mapping file in a separate VMFS volume that acts as a proxy for a raw physical storage device.
The RDM allows a virtual machine to directly access and use the storage device. The RDM contains
metadata for managing and redirecting disk access to the physical device.
The file gives you some of the advantages of direct access to a physical device while keeping some
advantages of a virtual disk in VMFS. As a result, it merges VMFS manageability with raw device access.
RDMs can be described in terms such as mapping a raw device into a datastore, mapping a system LUN, or
mapping a disk file to a physical disk volume. All these terms refer to RDMs.
Figure 18‑1. Raw Device Mapping
Virtual
machine
reads,
writes
opens
VMFS volume
mapping file
address
resolution
mapped device
Although VMware recommends that you use VMFS datastores for most virtual disk storage, on certain
occasions, you might need to use raw LUNs or logical disks located in a SAN.
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For example, you need to use raw LUNs with RDMs in the following situations:
n
When SAN snapshot or other layered applications run in the virtual machine. The RDM better enables
scalable backup offloading systems by using features inherent to the SAN.
n
In any MSCS clustering scenario that spans physical hosts — virtual-to-virtual clusters as well as
physical-to-virtual clusters. In this case, cluster data and quorum disks should be configured as RDMs
rather than as virtual disks on a shared VMFS.
Think of an RDM as a symbolic link from a VMFS volume to a raw LUN. The mapping makes LUNs appear
as files in a VMFS volume. The RDM, not the raw LUN, is referenced in the virtual machine configuration.
The RDM contains a reference to the raw LUN.
Using RDMs, you can:
n
Use vMotion to migrate virtual machines using raw LUNs.
n
Add raw LUNs to virtual machines using the vSphere Web Client.
n
Use file system features such as distributed file locking, permissions, and naming.
Two compatibility modes are available for RDMs:
n
Virtual compatibility mode allows an RDM to act exactly like a virtual disk file, including the use of
snapshots.
n
Physical compatibility mode allows direct access of the SCSI device for those applications that need
lower level control.
Benefits of Raw Device Mapping
An RDM provides a number of benefits, but it should not be used in every situation. In general, virtual disk
files are preferable to RDMs for manageability. However, when you need raw devices, you must use the
RDM.
RDM offers several benefits.
User-Friendly Persistent
Names
Provides a user-friendly name for a mapped device. When you use an RDM,
you do not need to refer to the device by its device name. You refer to it by
the name of the mapping file, for example:
/vmfs/volumes/myVolume/myVMDirectory/myRawDisk.vmdk
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Dynamic Name
Resolution
Stores unique identification information for each mapped device. VMFS
associates each RDM with its current SCSI device, regardless of changes in
the physical configuration of the server because of adapter hardware
changes, path changes, device relocation, and so on.
Distributed File Locking
Makes it possible to use VMFS distributed locking for raw SCSI devices.
Distributed locking on an RDM makes it safe to use a shared raw LUN
without losing data when two virtual machines on different servers try to
access the same LUN.
File Permissions
Makes file permissions possible. The permissions of the mapping file are
enforced at file-open time to protect the mapped volume.
File System Operations
Makes it possible to use file system utilities to work with a mapped volume,
using the mapping file as a proxy. Most operations that are valid for an
ordinary file can be applied to the mapping file and are redirected to operate
on the mapped device.
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Chapter 18 Raw Device Mapping
Snapshots
Makes it possible to use virtual machine snapshots on a mapped volume.
Snapshots are not available when the RDM is used in physical compatibility
mode.
vMotion
Lets you migrate a virtual machine with vMotion. The mapping file acts as a
proxy to allow vCenter Server to migrate the virtual machine by using the
same mechanism that exists for migrating virtual disk files.
Figure 18‑2. vMotion of a Virtual Machine Using Raw Device Mapping
Host 1
Host 2
VMotion
VM1
VM2
VMFS volume
mapping file
address
resolution
mapped device
SAN Management
Agents
Makes it possible to run some SAN management agents inside a virtual
machine. Similarly, any software that needs to access a device by using
hardware-specific SCSI commands can be run in a virtual machine. This kind
of software is called SCSI target-based software. When you use SAN
management agents, select a physical compatibility mode for the RDM.
N-Port ID Virtualization
(NPIV)
Makes it possible to use the NPIV technology that allows a single Fibre
Channel HBA port to register with the Fibre Channel fabric using several
worldwide port names (WWPNs). This ability makes the HBA port appear as
multiple virtual ports, each having its own ID and virtual port name. Virtual
machines can then claim each of these virtual ports and use them for all
RDM traffic.
Note You can use NPIV only for virtual machines with RDM disks.
VMware works with vendors of storage management software to ensure that their software functions
correctly in environments that include ESXi. Some applications of this kind are:
n
SAN management software
n
Storage resource management (SRM) software
n
Snapshot software
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n
Replication software
Such software uses a physical compatibility mode for RDMs so that the software can access SCSI devices
directly.
Various management products are best run centrally (not on the ESXi machine), while others run well on the
virtual machines. VMware does not certify these applications or provide a compatibility matrix. To find out
whether a SAN management application is supported in an ESXi environment, contact the SAN
management software provider.
RDM Considerations and Limitations
Certain considerations and limitations exist when you use RDMs.
n
The RDM is not available for direct-attached block devices or certain RAID devices. The RDM uses a
SCSI serial number to identify the mapped device. Because block devices and some direct-attach RAID
devices do not export serial numbers, they cannot be used with RDMs.
n
If you are using the RDM in physical compatibility mode, you cannot use a snapshot with the disk.
Physical compatibility mode allows the virtual machine to manage its own, storage-based, snapshot or
mirroring operations.
Virtual machine snapshots are available for RDMs with virtual compatibility mode.
n
You cannot map to a disk partition. RDMs require the mapped device to be a whole LUN.
n
If you use vMotion to migrate virtual machines with RDMs, make sure to maintain consistent LUN IDs
for RDMs across all participating ESXi hosts.
n
Flash Read Cache does not support RDMs in physical compatibility. Virtual compatibility RDMs are
supported with Flash Read Cache.
Raw Device Mapping Characteristics
An RDM is a special mapping file in a VMFS volume that manages metadata for its mapped device. The
mapping file is presented to the management software as an ordinary disk file, available for the usual filesystem operations. To the virtual machine, the storage virtualization layer presents the mapped device as a
virtual SCSI device.
Key contents of the metadata in the mapping file include the location of the mapped device (name
resolution), the locking state of the mapped device, permissions, and so on.
RDM Virtual and Physical Compatibility Modes
You can use RDMs in virtual compatibility or physical compatibility modes. Virtual mode specifies full
virtualization of the mapped device. Physical mode specifies minimal SCSI virtualization of the mapped
device, allowing the greatest flexibility for SAN management software.
In virtual mode, the VMkernel sends only READ and WRITE to the mapped device. The mapped device
appears to the guest operating system exactly the same as a virtual disk file in a VMFS volume. The real
hardware characteristics are hidden. If you are using a raw disk in virtual mode, you can realize the benefits
of VMFS such as advanced file locking for data protection and snapshots for streamlining development
processes. Virtual mode is also more portable across storage hardware than physical mode, presenting the
same behavior as a virtual disk file.
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In physical mode, the VMkernel passes all SCSI commands to the device, with one exception: the REPORT
LUNs command is virtualized so that the VMkernel can isolate the LUN to the owning virtual machine.
Otherwise, all physical characteristics of the underlying hardware are exposed. Physical mode is useful to
run SAN management agents or other SCSI target-based software in the virtual machine. Physical mode also
allows virtual-to-physical clustering for cost-effective high availability.
VMFS5 and VMFS6 support greater than 2 TB disk size for RDMs in virtual and physical modes.
Dynamic Name Resolution
The RDM file supports dynamic name resolution when a path to a raw device changes.
VMFS uniquely identifies all mapped storage devices, and the identification is stored in its internal data
structures. Any change in the path to a raw device, such as a Fibre Channel switch failure or the addition of
a new HBA, can change the device name. Dynamic name resolution resolves these changes and
automatically associates the original device with its new name.
Raw Device Mapping with Virtual Machine Clusters
Use an RDM with virtual machine clusters that need to access the same raw LUN for failover scenarios. The
setup is similar to that of a virtual machine cluster that accesses the same virtual disk file, but an RDM
replaces the virtual disk file.
Figure 18‑3. Access from Clustered Virtual Machines
Host 3
Host 4
VM3
VM4
“shared” access
mapping file
address
resolutiion
mapped
device
VMFS volume
Comparing Available SCSI Device Access Modes
The ways of accessing a SCSI-based storage device include a virtual disk file on a VMFS datastore, virtual
mode RDM, and physical mode RDM.
To help you choose among the available access modes for SCSI devices, the following table provides a quick
comparison of features available with the different modes.
Table 18‑1. Features Available with Virtual Disks and Raw Device Mappings
ESXi Features
Virtual Disk File
Virtual Mode RDM
Physical Mode RDM
SCSI Commands Passed
Through
No
No
Yes
REPORT LUNs is not passed
through
vCenter Server Support
Yes
Yes
Yes
Snapshots
Yes
Yes
No
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Table 18‑1. Features Available with Virtual Disks and Raw Device Mappings (Continued)
ESXi Features
Virtual Disk File
Virtual Mode RDM
Physical Mode RDM
Distributed Locking
Yes
Yes
Yes
Clustering
Cluster-in-a-box only
Cluster-in-a-box
cluster-across-boxes
Physical-to-virtual clustering
cluster-across-boxes
SCSI Target-Based Software
No
No
Yes
VMware recommends that you use virtual disk files for the cluster-in-a-box type of clustering. If you plan to
reconfigure your cluster-in-a-box clusters as cluster-across-boxes clusters, use virtual mode RDMs for the
cluster-in-a-box clusters.
Create Virtual Machines with RDMs
When you give your virtual machine direct access to a raw SAN LUN, you create an RDM disk that resides
on a VMFS datastore and points to the LUN. You can create the RDM as an initial disk for a new virtual
machine or add it to an existing virtual machine. When creating the RDM, you specify the LUN to be
mapped and the datastore on which to put the RDM.
Although the RDM disk file has the same.vmdk extension as a regular virtual disk file, the RDM contains
only mapping information. The actual virtual disk data is stored directly on the LUN.
This procedure assumes that you are creating a new virtual machine. For information, see the vSphere Virtual
Machine Administration documentation.
Procedure
1
Right-click any inventory object that is a valid parent object of a virtual machine, such as a data center,
folder, cluster, resource pool, or host, and select New Virtual Machine.
2
Select Create a new virtual machine and click Next.
3
Follow the steps required to create a virtual machine.
4
On the Customize Hardware page, click the Virtual Hardware tab.
5
(Optional) To delete the default virtual hard disk that the system created for your virtual machine,
move your cursor over the disk and click the Remove icon.
6
From the New drop-down menu at the bottom of the page, select RDM Disk and click Add.
7
From the list of SAN devices or LUNs, select a raw LUN for your virtual machine to access directly and
click OK.
The system creates an RDM disk that maps your virtual machine to the target LUN. The RDM disk is
shown on the list of virtual devices as a new hard disk.
8
Click the New Hard Disk triangle to expand the properties for the RDM disk.
9
Select a location for the RDM disk.
You can place the RDM on the same datastore where your virtual machine configuration files reside, or
select a different datastore.
Note To use vMotion for virtual machines with enabled NPIV, make sure that the RDM files and the
virtual machine files are located on the same datastore. You cannot perform Storage vMotion when
NPIV is enabled.
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10
11
Select a compatibility mode.
Option
Description
Physical
Allows the guest operating system to access the hardware directly.
Physical compatibility is useful if you are using SAN-aware applications
on the virtual machine. However, a virtual machine with a physical
compatibility RDM cannot be cloned, made into a template, or migrated if
the migration involves copying the disk.
Virtual
Allows the RDM to behave as if it were a virtual disk, so you can use such
features as taking snapshots, cloning, and so on. When you clone the disk
or make a template out of it, the contents of the LUN are copied into
a .vmdk virtual disk file. When you migrate a virtual compatibility mode
RDM, you can migrate the mapping file or copy the contents of the LUN
into a virtual disk.
If you selected virtual compatibility mode, select a disk mode.
Disk modes are not available for RDM disks using physical compatibility mode.
12
Option
Description
Dependent
Dependent disks are included in snapshots.
Independent - Persistent
Disks in persistent mode behave like conventional disks on your physical
computer. All data written to a disk in persistent mode are written
permanently to the disk.
Independent - Nonpersistent
Changes to disks in nonpersistent mode are discarded when you power off
or reset the virtual machine. With nonpersistent mode, you can restart the
virtual machine with a virtual disk in the same state every time. Changes
to the disk are written to and read from a redo log file that is deleted when
you power off or reset.
Click OK.
Manage Paths for a Mapped LUN
When you use virtual machines with RDMs, you can manage paths for mapped raw LUNs.
Procedure
1
In the vSphere Web Client, browse to the virtual machine.
2
Right-click the virtual machine and select Edit Settings.
3
Click the Virtual Hardware tab and click Hard Disk to expand the disk options menu.
4
Click Manage Paths.
5
Use the Edit Multipathing Policies dialog box to enable or disable paths, set multipathing policy, and
specify the preferred path.
For information on managing paths, see Chapter 17, “Understanding Multipathing and Failover,” on
page 181.
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Storage Policy Based Management
19
Storage Policy Based Management (SPBM) is a storage policy framework that provides a single unified
control pane across a broad range of data services and storage solutions. The framework helps to align
storage with application demands of your virtual machines.
SPBM enables the following mechanisms:
n
Advertisement of storage capabilities and data services that storage arrays and other entities, such as
I/O filters, offer.
n
Bidirectional communications between ESXi and vCenter Server on one side, and storage arrays and
entities on the other.
n
Virtual machine provisioning based on VM storage policies.
As an abstraction layer, SPBM abstracts storage services delivered by Virtual Volumes, Virtual SAN, I/O
filters, or other storage entities. Multiple partners and vendors can provide Virtual Volumes, Virtual SAN, or
I/O filters support. Rather than integrating with each individual vendor or type of storage and data service,
SPBM provides a universal framework for many types of storage solutions and entities.
UI
API/SDK
CLI
Storage Policy-Based Management (SPBM)
vSphere APIs for IO Filtering (VAIO)
I/O Filter
Vendors
Virtual
SAN
Virtual
Volumes
Traditional
(VMFS, NFS)
Storage
Vendors
Storage
Vendors
Storage
Vendors
This chapter includes the following topics:
n
“Virtual Machine Storage Policies,” on page 212
n
“Working with Virtual Machine Storage Policies,” on page 212
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n
“Populating the VM Storage Policies Interface,” on page 213
n
“Default Storage Policies,” on page 216
n
“Creating and Managing VM Storage Policies,” on page 218
n
“Storage Policies and Virtual Machines,” on page 227
Virtual Machine Storage Policies
One of the aspects of SPBM is virtual machine storage policies, which are essential to virtual machine
provisioning. The policies control which type of storage is provided for the virtual machine and how the
virtual machine is placed within storage. They also determine data services that the virtual machine can use.
vSphere offers default storage policies. In addition, you can define policies and assign them to the virtual
machines.
You use the VM Storage Policies interface to create a storage policy. When you define the policy, you specify
various storage requirements for applications that run on the virtual machines. You can also use storage
policies to request specific data services, such as caching or replication, for virtual disks.
You apply the storage policy when you create, clone, or migrate the virtual machine. After you apply the
storage policy, the SPBM mechanism assists you with placing the virtual machine in a matching datastore. In
certain storage environments, SPBM determines how the virtual machine storage objects are provisioned
and allocated within the storage resource to guarantee the required level of service. The SPBM also enables
requested data services for the virtual machine and helps you to monitor policy compliance.
Working with Virtual Machine Storage Policies
The entire process of creating and managing storage policies typically includes several steps. Whether you
must perform a specific step might depend on the type of storage or data services that your environment
offers.
1
Populate the VM Storage Policies interface with appropriate data.
The VM Storage Policies interface is populated with information about datastores and data services that
are available in your storage environment. This information is obtained from storage providers and
datastore tags.
a
For entities represented by storage providers, verify that an appropriate provider is registered.
Entities that use the storage provider include Virtual SAN, Virtual Volumes, and I/O filters.
Depending on the type of storage entity, some providers are self-registered. Other providers must
be manually registered. See “View Storage Provider Information,” on page 236 and “Register
Storage Providers for Virtual Volumes,” on page 250.
b
Tag datastores that are not represented by storage providers. You can also use tags to indicate a
property that is not communicated through the storage provider, such as geographical location or
administrative group.
See “Assign Tags to Datastores,” on page 215.
2
Create predefined storage policy components.
See “Create Storage Policy Components,” on page 221.
3
Create storage policies by defining requirements for applications that run on the virtual machine.
See “Define a Storage Policy for a Virtual Machine,” on page 223.
4
Apply the VM storage policy to the virtual machine.
You can apply the storage policy when deploying the virtual machine or configuring its virtual disks.
See “Assign Storage Policies to Virtual Machines,” on page 228.
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5
Verify that the virtual machine uses the datastore that is compliant with the assigned storage policy.
See “Check Compliance for a VM Storage Policy,” on page 230.
Populating the VM Storage Policies Interface
To define a VM storage policy, you use the VM Storage Policy interface. Before you can use the VM Storage
Policies interface, you must populate it with information about storage entities and data services that are
available in your storage environment.
This information is obtained from storage providers, also called VASA providers. Another source are
datastore tags.
Storage Capabilities and Data Services
Certain datastores, for example, Virtual Volumes and Virtual SAN, are represented by the storage providers.
Through the storage providers, the datastores can advertise their capabilities in the VM Storage Policy
interface. The lists of datastore capabilities, data services, and other characteristics with ranges of values
populate the VM Storage Policy interface.
You use these characteristics when you define capability-based placement rules for your storage policy.
The storage providers also represent I/O filters installed on your hosts. Through the storage provider,
information about the filter services automatically populates the VM Storage Policy interface. You include a
specific data service in a common rule of a VM storage policy. Unlike storage-specific placement rules,
common rules do not define storage placement and storage requirements for the virtual machine. Instead,
they activate the requested I/O filter data services for the virtual machine.
Tags
Generally, VMFS and NFS datastores are not represented by a storage provider and do not display their
capabilities and data services in the VM Storage Polices interface. You can use tags to encode information
about these datastores. For example, you can tag your VMFS datastores as VMFS-Gold and VMFS-Silver to
represent different levels of service.
You can also use tags to encode information that is not advertised by the storage provider, such as
geographical location (Palo Alto), or administrative group (Accounting).
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Similar to the storage capabilities and characteristics, all tags associated with the datastores appear in the
VM Storage Policies interface. You can use the tags when you define the tag-based placement rules.
Use Storage Providers to Populate the VM Storage Policies Interface
For entities represented by storage (VASA) providers, verify that an appropriate provider is registered. After
the storage providers are registered, the VM Storage Policies interface becomes populated with information
about datastores and data services that the providers represent.
Entities that use the storage provider include Virtual SAN, Virtual Volumes, and I/O filters. Depending on
the type of the entity, some providers are self-registered. Other providers, for example, the Virtual Volumes
storage provider, must be manually registered. After the storage providers are registered, they deliver the
following data to the VM Storage Policies interface:
n
Storage capabilities and characteristics for such datastores as Virtual Volumes and Virtual SAN
n
I/O filter characteristics
Prerequisites
Register the storage providers that require manual registration. For more information, see the appropriate
documentation:
n
Administering VMware Virtual SAN
n
Chapter 21, “Working with Virtual Volumes,” on page 239
n
Chapter 22, “Filtering Virtual Machine I/O,” on page 265
Procedure
1
Browse to vCenter Server in the vSphere Web Client navigator.
2
Click the Configure tab, and click Storage Providers.
3
In the Storage Providers list, view the storage providers registered with vCenter Server.
The list shows general information including the name of the storage provider, its URL and status,
storage entities that the provider represents, and so on.
4
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To display more details, select a specific storage provider or its component from the list.
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Assign Tags to Datastores
Use tags to encode information about a datastore. The tags are helpful when your datastore is not
represented by a storage provider and does not advertise its capabilities and data services in the VM Storage
Polices interface. You can also use the tags to indicate a property that is not communicated through a storage
provider, such as a geographical location or administrative group.
You can apply a new tag that contains general storage information to a datastore. For more details about the
tags, their categories, and how to manage the tags, see the vCenter Server and Host Management
documentation.
Prerequisites
Required privileges:
n
vSphere Tagging.Create vSphere Tag on the root vCenter Server instance
n
vSphere Tagging.Create vSphere Tag Category on the root vCenter Server instance
n
vSphere Tagging.Assign or Unassign vSphere Tag on the root vCenter Server instance
Procedure
1
Create a category for storage tags.
a
From the vSphere Web Client Home, click Tags & Custom Attributes.
b
Click the Tags tab and click Categories.
c
d
e
2
).
Specify the category options. See the following example.
Category Property
Example
Category Name
Storage Location
Description
Category for tags related to location of storage
Cardinality
Many tags per object
Associable Object Types
Datastore and Datastore Cluster
Click OK.
Create a storage tag.
a
b
c
d
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Click the New Category icon (
On the Tags tab, click Tags.
Click the New Tag icon (
).
Specify the properties for the tag. See the following example.
Tag Property
Example
Name
Texas
Description
Datastore located in Texas
Category
Storage Location
Click OK.
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3
Apply the tag to the datastore.
a
Browse to the datastore in the vSphere Web Client navigator.
b
Right-click the datastore, and selectTags & Custom Attributes > Assign Tag.
c
From the Categories drop-down menu, select the Storage Location category.
d
Select an appropriate tag, for example Texas, and click Assign.
The new tag is assigned to the datastore and appears on the datastore Summary tab in the Tags pane.
What to do next
When creating a VM storage policy, you can reference the tag to include the tagged datastore in the list of
compatible storage resources. See “Create Storage-Specific Rules for a VM Storage Policy,” on page 225.
Or you can exclude the tagged datastore from the VM storage policy. For example, your VM storage policy
can include Virtual Volumes datastores located in Taxes and California, but exclude datastores located in
Nevada.
Watch the following video to learn more about how to use tags in VM storage policies.
Using Tags in Storage Policies in the vSphere Web Client
(http://link.brightcove.com/services/player/bcpid2296383276001?
bctid=ref:video_tags_in_datastores_webclient)
Default Storage Policies
When you provision a virtual machine on an object-based datastore, you must assign to the virtual machine
a compatible virtual machine storage policy. The object-based datastores include Virtual SAN or Virtual
Volumes. This assignment guarantees the optimum placement for the virtual machine objects within the
object-based storage. If you do not explicitly assign the storage policy to the virtual machine, the system
uses a default storage policy that is associated with the datastore. The default policy is also used when the
policy that you assign does not include rules specific to Virtual Volumes or Virtual SAN.
VMware providers the default storage policies for Virtual SAN and Virtual Volumes. Alternatively, you can
define the default policy. VMFS and NFS datastores do not have default policies.
Default Policies Provided by VMware
VMware provides default storage policies for Virtual SAN and Virtual Volumes datastores.
Virtual SAN Default Storage Policy
When you do not select any Virtual SAN policy, the system applies the default storage policy to all virtual
machine objects that are provisioned on a Virtual SAN datastore.
The default Virtual SAN policy that VMware provides has the following characteristics:
216
n
You cannot delete the policy.
n
The policy is editable. To edit the policy, you must have the storage policy privileges that include the
view and update privileges.
n
When editing the policy, you cannot change the name of the policy or the Virtual SAN storage provider
specification. All other parameters including rules are editable.
n
You can clone the default policy and use the copy as a template to create another storage policy.
n
The Virtual SAN default policy is compatible only with Virtual SAN datastores.
n
You can create a VM storage policy for Virtual SAN and designate it as the default.
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Virtual Volumes Default Storage Policy
For Virtual Volumes, VMware provides a default storage policy that contains no rules or storage
requirements, called VVol No Requirements Policy. As with Virtual SAN, this policy is applied to the VM
objects when you do not specify another policy for the virtual machine on the Virtual Volumes datastore.
With the No Requirements policy, storage arrays can determine the optimum placement for the VM objects.
The default No Requirements policy that VMware provides has the following characteristics:
n
You cannot delete, edit, or clone this policy.
n
The policy is compatible only with the Virtual Volumes datastores.
n
You can create a VM storage policy for Virtual Volumes and designate it as the default.
User-Defined Default Policies for Virtual Machine Storage
You can create a VM storage policy that is compatible with Virtual SAN or Virtual Volumes. You can then
designate this policy as the default for Virtual SAN and Virtual Volumes datastores. The user-defined
default policy replaces the default storage policy that VMware provides.
Each Virtual SAN and Virtual Volumes datastore can have only one default policy at a time. However, you
can create a single storage policy with multiple rule sets, so that it matches multiple Virtual SAN and Virtual
Volumes datastores. You can designate this policy as the default policy for all datastores.
When the VM storage policy becomes the default policy for a datastore, you cannot delete the policy unless
you disassociate it from the datastore.
Change the Default Storage Policy for a Datastore
For Virtual Volumes and Virtual SAN datastores, VMware provides storage policies that are used as the
default during the virtual machine provisioning. You can change the default storage policy for a selected
Virtual Volumes or Virtual SAN datastore.
Note A storage policy that contains replication rules should not be specified as a default storage policy.
Otherwise, the policy prevents you from selecting replication groups.
Prerequisites
Create a storage policy that is compatible with Virtual Volumes or Virtual SAN. You can create a policy that
matches both types of storage.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the datastore.
3
Click the Configure tab.
4
Under Settings, click General.
5
Click Edit in the Default Storage Policy pane.
6
From the list of available storage policies, select a policy to designate as the default and click OK.
The selected storage policy becomes the default policy for the datastore. vSphere assigns this policy to any
virtual machine objects that you provision on the datastore when no other policy is selected.
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Creating and Managing VM Storage Policies
To create and manage storage policies for your virtual machines, you use the VM Storage Policies interface
of the vSphere Web Client.
After the VM Storage Policies interface is populated with the appropriate data, you can start creating your
storage policies. When you create a storage policy, you define placement and data service rules. The rules
are the basic element of the VM storage policy. Within the policy, the rules are grouped in collections of
rules, or rule sets.
In certain cases, you can prepackage the rules in storage policy components. The components are modular
building blocks that you define in advance and can reference in multiple storage policies.
After you create the storage policy, you can edit or clone it, or delete any unused policies.
About Datastore-Specific and Common Rule Sets
After the VM Storage Policies interface is populated with the appropriate data, you can start defining your
storage policies. A basic element of a VM storage policy is a rule. Each individual rule is a statement that
describes a single requirement for virtual machine storage and data services. Within the policy, rules are
grouped in collections of rules. Two types of collections exist, regular rule sets and common rule sets.
Regular Rule Sets
Regular rule sets are datastore-specific. Each rule set must include placement
rules that describe requirements for virtual machine storage resources. All
placement rules within a single rule set represent a single storage entity.
These rules can be based on tags or storage capabilities. In addition, the
regular rule set can include optional storage policy components that describe
data services to provide for the virtual machine.
To define the storage policy, one regular rule set is required. Additional rule
sets are optional. A single policy can use multiple rule sets to define
alternative storage placement parameters, often from several storage
providers.
Common Rule Sets
Unlike datastore-specific regular rule sets, common rule sets do not define
storage placement for the virtual machine, and do not include placement
rules. Common rule sets are generic for all types of storage and do not
depend on the datastore. These rule sets activate data services for the virtual
machine. Common rule sets include rules or storage policy components that
describe particular data services, such as encryption, replication, and so on.
Table 19‑1. Structure of a VM Storage Policy
Common Rules
Regular Rule Sets
Rules or predefined storage policy components to activate
data services installed on ESXi hosts. For example,
replication by I/O filters.
Placement rules that describe requirements for virtual
machine storage resources. For example, Virtual Volumes
placement.
Rules or predefined storage policy components that
activate data services provided by storage. For example,
caching by Virtual Volumes.
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Relationships Between Rules and Rule Sets
The Boolean operator OR defines the relationship between the regular rule sets within the policy. The AND
operator defines the relationship between all rules within a single rule set. The policy can contain only
common rules, or only datastore-specific rule sets, or both. If common rules are not present, meeting all the
rules of a single regular rule set is sufficient to satisfy the entire policy. When common rules are present, the
policy matches the datastore that can satisfy all common rules and all rules in at least one of the regular rule
sets.
Virtual machine storage policy
Common rules
rule 1 and rule 2
Rule set 1
Rule set 2
Rule set 3
rule 1_1
rule 2_1
rule 3_1
rule 1_2
or
rule 2_2
rule 1_3
or
rule 3_2
rule 3_3
About Rules
Rules are the basic elements of a VM storage policy. Each individual rule is a statement that describes a
single requirement for virtual machine storage and data services.
Typically, rules can be in one of the following categories: placement rules, including capability-based and
tag-based, and data services rules. Within a storage policy, individual rules are organized into collections of
rules, or rule sets.
Placement Rules: Capability-Based
Placement rules specify a particular storage requirement for the VM and enable SPBM to distinguish
compatible datastores among all datastores in the inventory. These rules also describe how the virtual
machine storage objects are allocated within the datastore to receive the required level of service. For
example, the rules can list Virtual Volumes as a destination and define the maximum recovery point
objective (RPO) for the Virtual Volumes objects. When you provision the virtual machine, these rules guide
the decision that SPBM makes about the virtual machine placement. SPBM finds the Virtual Volumes
datastores that can match the rules and satisfy the storage requirements of the virtual machine.
Placement Rules: Tag-Based
Tag-based rules reference datastore tags. These rules can define your VM placement, for example, request as
a target all datastores with the VMFS-Gold tag. You can also use the tag-based rules to fine-tune your VM
placement request further. For example, exclude datastores with the Palo Alto tag from the list of your
Virtual Volumes datastores.
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Data Service Rules
Unlike the placement rules, the data service rules do not define storage placement and storage requirements
for the virtual machine. Instead, these rules activate specific data services for the virtual machine, for
example, caching and replication. Storage systems or other entities can provide these services. They can also
be installed on your hosts and vCenter Server. You include the data service rules in the storage policy
components. If the data service is provided by a storage system, you add the components to the regular rule
sets. If the data service is provided by I/O filters, the component is added to the common rule set.
About Storage Policy Components
A VM storage policy can include one or several reusable and interchangeable building blocks, called storage
policy components. Each component describes a particular data service to be provided for the virtual
machine. You can define the policy components in advance and associate them with multiple VM storage
policies.
You cannot assign the predefined component directly to a virtual machine or virtual disk. Instead, you must
add the component to the VM storage policy, and assign the policy to the virtual machine.
The component describes one type of service from one service provider. The services can vary depending on
the providers that you use, but generally belong in one of the following categories.
n
Compression
n
Caching
n
Encryption
n
Replication
When you create the storage policy component, you define the rules for one specific type and grade of
service.
The following example shows that virtual machines VM1 and VM2 have identical placement requirements,
but must have different grades of replication services. You can create the storage policy components with
different replication parameters and add these components to the related storage policies.
Table 19‑2. Storage Policy Components
Virtual Machine
VM Storage Policy
Storage Policy Component
VM1 requires replication every 2 hours
SP1
2-hour Replication
VM2 requires replication every 4 hours
SP2 (clone of SP1)
4-hour Replication
The provider of the service can be a storage system, an I/O filter, or another entity. If the component
references an I/O filter, the component is added to the common rule set of the storage policy. Components
that reference entities other than the I/O filters, for example, a storage system, are added to regular rule sets
with placement rules.
When you work with the components, follow these guidelines:
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n
Each component can include only one set of rules. All characteristics in this rule set belong to a single
provider of the data services.
n
If the component is referenced in the VM storage policy, you cannot delete the component. Before
deleting the component, you must remove it from the storage policy or delete the storage policy.
n
When you add components to the policy, you can use only one component from the same category, for
example caching, per a set of rules.
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Create Storage Policy Components
A storage policy component describes a single data service, such as replication, that must be provided for
the virtual machine. You can define the component in advance and associate it with multiple VM storage
policies. The components are reusable and interchangeable.
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the Storage Policy Components tab, and click the Create Storage Policy Component icon.
3
Select the vCenter Server instance.
4
Enter a name, for example, 4-hour Replication, and a description for the policy component.
Make sure that the name does not conflict with the names of other components or storage policies.
5
Select the category of the service, for example, Replication.
6
Select the service provider.
7
Define rules for the selected category.
For example, if you are configuring 4-hour replication, set the Recovery Point Objective (RPO) value to
4.
For encryption based on I/O filters, set the Allow I/O filters before encryption parameter. Encryption
provided by storage does not require this parameter.
8
Option
Description
False (default)
Does not allow the use of other I/O filters before the encryption filter.
True
Allows the use of other I/O filters before the encryption filter. Other filters,
such as replication, can analyze clear text data before it is encrypted.
Click OK.
The new component appears in the list of storage policy components.
What to do next
You can add the component to the VM storage policy. If the data service that the component references, such
as replication, is provided by the I/O filters, you add the component to the common rules set. If the data
service is provided by the storage system, you add the component to the regular rule set.
View Storage Policy Components
After you create a storage policy component, you can view its details and perform other management tasks.
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the Storage Policy Components tab.
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3
View the details for the selected storage policy component.
a
Select the component.
b
Switch between the following tabs.
Menu Item
Description
Content
Display rules and their related values.
Used In
List VM storage policies that reference the component.
What to do next
Use the Storage Policy Components tab to edit, clone, or delete the selected storage policy component.
Edit or Clone Storage Policy Components
You can modify the existing storage policy components. You can also create a copy of the existing
component by cloning it.
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the Storage Policy Components tab, and select the component to edit or clone.
3
Click one of the following icons:
4
n
Edit Settings
n
Clone
Modify appropriate values.
When editing, you cannot change the category of the data service and the provider. For example, if
original component references replication provided by I/O filters, these settings must remain
unchanged. When cloning, you can customize any settings of the original component.
5
To save your changes, click OK.
6
If a VM storage policy that is assigned to a virtual machine references the policy component you edit,
reapply the storage policy to the virtual machine.
Menu Item
Description
Manually later
If you select this option, the compliance status for all virtual disks and
virtual machine home objects associated with the storage policy changes to
Out of Date. To update configuration and compliance, manually reapply
the storage policy to all associated entities. See “Reapply Virtual Machine
Storage Policy,” on page 232.
Now
Update virtual machine and compliance status immediately after editing
the storage policy.
Delete Storage Policy Components
You can delete unused storage policy components.
Prerequisites
Verify that the component is not used in a VM storage policy. If it is used, either remove it from the policy or
delete the policy. The Used In tab of the component lists the VM storage policies that reference the
component.
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Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the Storage Policy Components tab, and select the component to delete from the list.
You can select several components.
3
Click the Delete icon and confirm that you want to delete the component.
The component is removed from the list of storage policy components.
Define a Storage Policy for a Virtual Machine
When you define storage policies for virtual machines, you specify storage requirements for applications
that run on the virtual machines.
A storage policy can reference storage capabilities that are advertised by a storage entity. Or it can reference
datastore tags. The policy can include components that enable data services, such as replication or caching,
provided by I/O filters, storage systems, or other entities.
Prerequisites
n
Make sure that the VM Storage Policies interface is populated with information about storage entities
and data services that are available in your storage environment. See “Populating the VM Storage
Policies Interface,” on page 213.
n
Define appropriate storage policy components. See “Create Storage Policy Components,” on page 221.
n
Required privileges: VM storage policies.Update and VM storage policies.View.
Procedure
1
Start VM Storage Policy Creation Process on page 223
To define a virtual machine storage policy, use the Create New VM Storage Policy wizard.
2
Define Common Rules for a VM Storage Policy on page 224
On the Common rules page, specify which data services to include in the VM storage policy. The data
services are provided by software components that are installed on your ESXi hosts and
vCenter Server. The VM storage policy that includes common rules activates specified data services for
the virtual machine.
3
Create Storage-Specific Rules for a VM Storage Policy on page 225
Use the Rule Set page to define storage placement rules. If your storage provides additional data
services, such as replication, use the page to specify which data services to include in the VM storage
policy.
4
Finish VM Storage Policy Creation on page 226
You can review the list of datastores that are compatible with the VM storage policy and change any
storage policy settings.
What to do next
You can apply this storage policy to virtual machines. If you use object-based storage, such as Virtual SAN
and Virtual Volumes, you can designate this storage policy as the default.
Start VM Storage Policy Creation Process
To define a virtual machine storage policy, use the Create New VM Storage Policy wizard.
Procedure
1
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From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
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2
Click the VM Storage Policies tab.
3
Click the Create a New VM Storage Policy icon.
4
Select the vCenter Server instance.
5
Type a name and a description for the storage policy.
Define Common Rules for a VM Storage Policy
On the Common rules page, specify which data services to include in the VM storage policy. The data
services are provided by software components that are installed on your ESXi hosts and vCenter Server. The
VM storage policy that includes common rules activates specified data services for the virtual machine.
The data services are generic for all types of storage and do not depend on a datastore. Depending on your
environment, the data services can belong to various categories, including encryption, caching, replication,
and so on. Certain data services, such as encryption, are provided by VMware. Others are offered by thirdparty I/O filters.
Prerequisites
n
For information about encrypting your virtual machines, see the vSphere Security documentation.
n
For information about I/O filters, see Chapter 22, “Filtering Virtual Machine I/O,” on page 265.
n
For information about storage policy components, see “About Storage Policy Components,” on
page 220.
Procedure
1
Enable common rules by selecting Use common rules in the VM storage policy.
2
Click the Add component (
example, Replication.
3
Define rules for the data service category by specifying an appropriate provider and values for the
rules. Or select the data service from the list of predefined components.
Option
Component Name
4
) icon and select a data service category from the drop-down menu, for
Description
This option is available if you have predefined storage policy components
in your database. If you know which component to use, select it from the
list to add to the VM storage policy.
See all
Review all component available for the category. To include a specific
component, select it from the list and click OK.
Custom
Define custom rules for the data service category by specifying an
appropriate provider and values for the rules.
Add more components to request other data services.
You can use only one component from the same category, for example caching, per a set of common or
regular rules.
5
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Create Storage-Specific Rules for a VM Storage Policy
Use the Rule Set page to define storage placement rules. If your storage provides additional data services,
such as replication, use the page to specify which data services to include in the VM storage policy.
Prerequisites
n
If your environment includes storage entities such as Virtual SAN or Virtual Volumes, review these
functionalities. For information, see the Administering VMware Virtual SAN documentation and
Chapter 21, “Working with Virtual Volumes,” on page 239.
n
To configure predefined storage policy components, see “About Storage Policy Components,” on
page 220.
Procedure
1
Make sure that the Use rule-sets in the storage policy check box is selected.
2
Define placement rules.
Placement rules request a specific storage entity as a destination for the virtual machine. They can be
capability-based or tag-based. Capability-based rules are based on data services that storage entities
such as Virtual SAN and Virtual Volumes advertise through storage (VASA) providers. Tag-based rules
reference tags that you assign to datastores.
Option
Description
Placement based on storage
capabilities
a
b
c
From the Storage Type drop-down menu, select a target storage entity,
for example, Virtual Volumes.
From theAdd rule drop-down menu, select a capability and specify its
value.
For example, you can specify the number of read operations per
second for Virtual Volumes objects. You can include as many rules as
you need for the selected storage entity. Verify that the values you
provide are within the range of values that the storage resource
advertises.
If you need to fine-tune your placement request further, add a tagbased rule.
Tag-based rules can include or exclude specific placement criteria. For
example, you can exclude datastores with the Palo Alto tag from the
list of your target Virtual Volumes datastores.
Placement based on tags
a
b
c
From the Storage Type drop-down menu, select Tags based
placement.
From theAdd rule drop-down menu, select Tags from category.
Define tag-based placement criteria.
For example, you can request as a target all datastores with the VMFSGold tag.
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3
(Optional) Select data services to include in the VM storage policy.
The data services that you reference on the Rule Set page are provided by the storage. The VM storage
policy that references the data services, requests them for the virtual machine.
a
Click the Add component (
for example, Replication.
b
Define rules for the data service category by specifying an appropriate provider and values for the
rules. Or select the data service from the list of predefined components.
) icon and select a data service category from the drop-down menu,
Option
Component Name
c
Description
This option is available if you have predefined storage policy
components in your database. If you know which component to use,
select it from the list to add to the VM storage policy.
See all
Review all component available for the category. To include a specific
component, select it from the list and click OK.
Custom
Define custom rules for the data service category by specifying an
appropriate provider and values for the rules.
Add more components to request other data services.
You can use only one component from the same category, for example caching, per a set of common
or regular rules.
4
(Optional) To define another rule set, click Add another rule set and repeat Step 2 through Step 3.
Multiple rule sets allow a single policy to define alternative storage placement parameters, often from
several storage providers.
5
Click Next.
Finish VM Storage Policy Creation
You can review the list of datastores that are compatible with the VM storage policy and change any storage
policy settings.
Procedure
1
On the Storage compatibility page, review the list of datastores that match this policy and click Next.
To be eligible, the datastore must satisfy at least one rule set and all rules within this set.
2
On the Ready to complete page, review the storage policy settings.
If you need to change any settings, click Back to go back to the relevant page.
3
Click Finish.
The VM storage policy appears in the list.
Delete a Virtual Machine Storage Policy
You can delete a storage policy if you are not planning to use it.
You cannot delete the VVols No Requirement Policy and Virtual SAN Default Policy.
Prerequisites
n
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If the policy you want to delete is used as the default, disassociate it from the datastore. See “Change
the Default Storage Policy for a Datastore,” on page 217.
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n
If the policy is used by a virtual machine, change the VM policy assignment. See “Change Storage
Policy Assignment for Virtual Machine Files and Disks,” on page 228.
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the VM Storage Policies tab.
3
Select the policy to delete and click the Delete icon ( ).
You can select multiple policies.
4
Click Yes to confirm your action.
The policy is removed from the inventory.
Edit or Clone a VM Storage Policy
If storage requirements for virtual machines and virtual disks change, you can modify the existing storage
policy. You can also create a copy of the existing VM storage policy by cloning it. While cloning, you can
optionally select to customize the original storage policy.
Prerequisites
Required privilege: StorageProfile.View
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the VM Storage Policies tab.
3
Select a storage policy, and click one of the following icons:
n
Edit a VM storage policy
n
Clone a VM storage policy
4
(Optional) Modify the policy and click OK.
5
If editing the storage policy that is used by a virtual machine, reapply the policy to the virtual machine.
Option
Description
Manually later
If you select this option, the compliance status for all virtual disks and
virtual machine home objects associated with the storage policy changes to
Out of Date. To update configuration and compliance, manually reapply
the storage policy to all associated entities. See “Reapply Virtual Machine
Storage Policy,” on page 232.
Now
Update virtual machine and compliance status immediately after editing
the storage policy.
Storage Policies and Virtual Machines
After you define a VM storage policy, you can apply it to a virtual machine. You apply the storage policy
when provisioning the virtual machine or configuring its virtual disks. Depending on its type and
configuration, the policy might serve different purposes. The policy can select the most appropriate
datastore for the virtual machine and enforce the required level of service. Or it can enable specific data
services for the virtual machine and its disks.
If you do not specify the storage policy, the system uses a default storage policy that is associated with the
datastore. If your storage requirements for the applications on the virtual machine change, you can modify
the storage policy that was originally applied to the virtual machine.
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Assign Storage Policies to Virtual Machines
You can assign a VM storage policy in an initial deployment of a virtual machine or when you perform other
virtual machine operations, such as cloning or migrating.
This topic describes how to assign the VM storage policy when you create a virtual machine. For
information about other deployment methods that include cloning, deployment from a template, and so on,
see the vSphere Virtual Machine Administration documentation.
You can apply the same storage policy to the virtual machine configuration file and all its virtual disks. If
storage requirements for your virtual disks and the configuration file are different, you can associate
different storage policies with the VM configuration file and the selected virtual disks.
Procedure
1
In the vSphere Web Client, start the virtual machine provisioning process and follow the appropriate
steps.
2
Assign the same storage policy to all virtual machine files and disks.
a
On the Select storage page, select a storage policy from the VM Storage Policy drop-down menu.
Based on its configuration, the storage policy separates all datastores into compatible and
incompatible sets. If the policy references data services offered by a specific storage entity, for
example, Virtual Volumes, the compatible list includes datastores that represent only that type of
storage.
b
Select an appropriate datastore from the list of compatible datastores.
The datastore becomes the destination storage resource for the virtual machine configuration file
and all virtual disks.
3
Change the VM storage policy for the virtual disk.
Use this option if requirements for storage placement are different for virtual disks. You can also use
this option to enable I/O filter services, such as caching and replication, for your virtual disks.
a
On the Customize hardware page, expand the New hard disk pane.
b
From the VM storage policy drop-down menu, select the storage policy to assign to the virtual
disk.
c
(Optional) Change the storage location of the virtual disk.
Use this option to store the virtual disk on a datastore other than the datastore where the VM
configuration file resides.
4
Complete the virtual machine provisioning process.
After you create the virtual machine, the Summary tab displays the assigned storage policies and their
compliance status.
What to do next
If storage placement requirements for the configuration file or the virtual disks change, you can later modify
the virtual policy assignment.
Change Storage Policy Assignment for Virtual Machine Files and Disks
If your storage requirements for the applications on the virtual machine change, you can edit the storage
policy that was originally applied to the virtual machine.
You can edit the storage policy for a powered-off or powered-on virtual machine.
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When changing the VM storage policy assignment, you can apply the same storage policy to the virtual
machine configuration file and all its virtual disks. If storage requirements for your virtual disks and the
configuration file are different, you can associate different storage policies with the VM configuration file
and the selected virtual disks.
Procedure
1
Browse to the virtual machine.
a
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
b
Click the storage policy you want to change.
c
Click the VMs tab and click Virtual Machines.
You can see the list of virtual machines that use this storage policy.
d
From the list, select the virtual machine whose policy you want to modify.
2
Click the Configure tab and click Policies.
3
Click Edit VM Storage Policies.
4
Specify the VM storage policy for your virtual machine.
5
Option
Actions
Apply the same storage policy to all
virtual machine objects.
a
b
Select the policy from the VM storage policy drop-down menu.
Click Apply to all.
Apply different storage policies to
the VM home object and virtual
disks.
a
b
Select the object.
In the VM Storage Policy column, select the policy from the dropdown menu.
If you use Virtual Volumes policy with replication, configure the replication group.
Replication groups indicate which VMs and virtual disks need to be replicated together to a target site.
a
Click Configure to open the Configure VM Replication Groups page.
b
Specify the replication group.
c
6
Option
Actions
Assign the same replication group
to all virtual machine objects.
Select Common replication gourp and select a preconfigured or
automatic group form the drop-down menu.
Assign different replication
groups to the VM home object and
virtual disks.
1
2
3
Select Replication gorup per storage object.
Select the object to modify.
In the Replication Group column, select the replication group from
the drop-down menu.
Click OK.
Click OK to save the VM storage policy changes.
The storage policy is assigned to the virtual machine and its disks.
Monitor Storage Compliance for Virtual Machines
When you associate a policy with virtual machine objects and select the datastores on which virtual
machines and virtual disks run, you can check whether virtual machines and virtual disks use datastores
that are compliant with the policy.
If you check the compliance of a virtual machine whose host or cluster has storage policies disabled, the
result of the check is Noncompliant because the feature is disabled.
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Prerequisites
To perform a compliance check for a storage policy, associate the policy with at least one virtual machine or
virtual disk.
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Double-click a storage policy.
3
Click the Monitor tab, and click VMs and Virtual Disks.
4
Click Trigger VM storage policy compliance check ( ) icon.
The Compliance Status column shows the storage compliance status for virtual machines and their
policies.
Compliance Status
Description
Compliant
The datastore that the virtual machine or virtual disk uses has the storage capabilities that are
required by the policy.
Noncompliant
The datastore supports specified storage requirements, but cannot currently satisfy the
virtual machine storage policy. For example, the status might become Not Compliant when
physical resources that back up the datastore are unavailable or exhausted. You can bring the
datastore into compliance by making changes in the physical configuration, for example, by
adding hosts or disks to the cluster. If additional resources satisfy the virtual machine storage
policy, the status changes to Compliant.
Out of Date
The status indicates that the policy has been edited, but the new requirements have not been
communicated to the datastore where the virtual machine objects reside. To communicate the
changes, reapply the policy to the objects that are out of date.
Not Applicable
This storage policy references datastore capabilities that are not supported by the datastore
where the virtual machine resides.
What to do next
When you cannot bring the noncompliant datastore into compliance, migrate the files or virtual disks to a
compatible datastore. See “Find Compatible Storage Resource for Noncompliant Virtual Machine,” on
page 231.
If the status is Out of Date, reapply the policy to the objects. See “Reapply Virtual Machine Storage Policy,”
on page 232.
Check Compliance for a VM Storage Policy
You can check whether a virtual machine uses a datastore that is compatible with the storage requirements
specified in the VM storage policy.
Prerequisites
Verify that the virtual machine has a storage policy that is associated with it.
Procedure
1
In the vSphere Web Client, browse to the virtual machine.
2
From the right-click menu, select VM Policies > Check VM Storage Policy Compliance.
The system verifies the compliance.
3
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Click the Summary tab for the virtual machine.
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4
View the compliance status in the VM Storage Policies pane.
Compliance Status
Description
Compliant
The datastore that the virtual machine or virtual disk uses has the storage capabilities that are
required by the policy.
Noncompliant
The datastore supports specified storage requirements, but cannot currently satisfy the
virtual machine storage policy. For example, the status might become Not Compliant when
physical resources that back up the datastore are unavailable or exhausted. You can bring the
datastore into compliance by making changes in the physical configuration, for example, by
adding hosts or disks to the cluster. If additional resources satisfy the virtual machine storage
policy, the status changes to Compliant.
Out of Date
The status indicates that the policy has been edited, but the new requirements have not been
communicated to the datastore where the virtual machine objects reside. To communicate the
changes, reapply the policy to the objects that are out of date.
Not Applicable
This storage policy references datastore capabilities that are not supported by the datastore
where the virtual machine resides.
What to do next
When you cannot bring the noncompliant datastore into compliance, migrate the files or virtual disks to a
compatible datastore. See “Find Compatible Storage Resource for Noncompliant Virtual Machine,” on
page 231.
If the status is Out of Date, reapply the policy to the objects. See “Reapply Virtual Machine Storage Policy,”
on page 232.
Find Compatible Storage Resource for Noncompliant Virtual Machine
Determine which datastore is compatible with the storage policy that is associated with your virtual
machine.
Occasionally, a storage policy that is assigned to a virtual machine can be in the noncompliant status. This
status indicates that the virtual machine or its disks use datastores that are incompatible with the policy. You
can migrate the virtual machine files and virtual disks to compatible datastores.
Use this task to determine which datastores satisfy the requirements of the policy.
Prerequisites
Verify that the VM Storage Policy Compliance field on the virtual machine Summary tab displays the Not
Compliant status.
Procedure
1
In the vSphere Web Client, browse to the virtual machine.
2
Click the Summary tab.
The VM Storage Policy Compliance panel on the VM Storage Policies pane shows the Not Compliant
status.
3
Click the policy link in the VM Storage Policies panel.
4
Click the Monitor tab and click VMs and Virtual Disks to determine which virtual machine files are
noncompliant.
5
Click Storage Compatibility.
The list of datastores that match the requirements of the policy appears.
What to do next
You can migrate the virtual machine or its disks to one of the datastores in the list.
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Reapply Virtual Machine Storage Policy
After you edit a storage policy that is already associated with a virtual machine object, you must reapply the
policy. By reapplying the policy, you communicate new storage requirements to the datastore where the
virtual machine object resides.
Prerequisites
The compliance status for a virtual machine is Out of Date. The status indicates that the policy has been
edited, but the new requirements have not been communicated to the datastore.
Procedure
232
1
In the vSphere Web Client, browse to the virtual machine.
2
Click the Configure tab and click Policies.
3
Verify that the compliance status is Out of Date.
4
Click the Reapply VM storage policy to all out of date entities icon (
5
Check the compliance status.
).
Compliance Status
Description
Compliant
The datastore that the virtual machine or virtual disk uses has the storage capabilities that the
policy requires.
Noncompliant
The datastore that the virtual machine or virtual disk uses does not have the storage
capabilities that the policy requires. You can migrate the virtual machine files and virtual
disks to compliant datastores.
When you cannot bring the noncompliant datastore into compliance, migrate the files or
virtual disks to a compatible datastore. See “Find Compatible Storage Resource for
Noncompliant Virtual Machine,” on page 231.
Not Applicable
This storage service level references datastore capabilities that are not supported by the
datastore where the virtual machine resides.
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Using Storage Providers
20
A storage provider is a software component that is either offered by VMware or is developed by a third
party through the vSphere APIs for Storage Awareness (VASA) program. The storage provider can also be
called VASA provider. The storage providers integrate with various storage entities that include external
physical storage and storage abstractions, such as Virtual SAN and Virtual Volumes. Storage providers can
also support software solutions, for example, I/O filters.
Generally, vCenter Server and ESXi use the storage providers to obtain information about storage
configuration, status, and storage data services offered in your environment. This information appears in the
vSphere Web Client. The information helps you to make appropriate decisions about virtual machine
placement, to set storage requirements, and to monitor your storage environment.
Storage providers that manage arrays and storage abstractions, are called persistence storage providers.
Providers that support Virtual Volumes or Virtual SAN belong to this category. In addition to storage,
persistence providers can provider other data services, such as replication.
Another category of providers is I/O filter storage providers, or data service providers. These providers offer
data services that include host based caching, compression, and encryption.
Built-in storage providers typically do not require registration. For example, the storage providers that
support I/O filters become registered automatically.
When a third party offers a storage provider, you typically must register the provider. An example of such a
provider is the Virtual Volumes provider. You use the vSphere Web Client to register and manage each
storage provider component.
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The following graphic illustrates how different types of storage providers facilitate communication between
vCenter Server and ESXi and other components of your storage environment, such as storage arrays, Virtual
Volumes storage, and I/O filters.
vCenter
Server
SPBM
I/O Filter
Storage
Provider
I/O
Filter
ESXi-1
X100 Array
Multi-Array
Storage
Provider
I/O
Filter
VVols
Storage
Provider
ESXi-2
X200 Array
Virtual
Volumes
Storage
This chapter includes the following topics:
n
“Storage Providers and Data Representation,” on page 234
n
“Storage Provider Requirements and Considerations,” on page 235
n
“Register Storage Providers,” on page 235
n
“View Storage Provider Information,” on page 236
n
“Unregister Storage Providers,” on page 236
n
“Update Storage Providers,” on page 237
n
“Refresh Storage Provider Certificates,” on page 237
Storage Providers and Data Representation
vCenter Server and ESXi communicate with the storage provider to obtain information that the storage
provider collects from underlying physical and software-defined storage, or from available I/O filters.
vCenter Server can then display the storage data in the vSphere Web Client.
Information that the storage provider supplies can be divided into the following categories:
n
Storage data services and capabilities. This type of information is essential for such functionalities as
Virtual SAN, Virtual Volumes, and I/O filters. The storage provider that represents these functionalities
integrates with the Storage Policy Based Management (SPBM) mechanism. The storage provider collects
information about data services that are offered by underlying storage entities or available I/O filters.
You reference these data services when you define storage requirements for virtual machines and
virtual disks in a storage policy. Depending on your environment, the SPBM mechanism ensures
appropriate storage placement for a virtual machine or enables specific data services for virtual disks.
For details, see “Creating and Managing VM Storage Policies,” on page 218.
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n
Storage status. This category includes reporting about status of various storage entities. It also includes
alarms and events for notifying about configuration changes.
This type of information can help you troubleshoot storage connectivity and performance problems. It
can also help you to correlate array-generated events and alarms to corresponding performance and
load changes on the array.
n
Storage DRS information for the distributed resource scheduling on block devices or file systems.
Storage providers supply additional information about the storage systems, so that decisions made by
Storage DRS are compatible with resource management decisions internal to the storage systems.
Storage Provider Requirements and Considerations
When you use the third-party storage providers, certain requirements and considerations apply.
Typically, vendors are responsible for supplying storage providers. The VMware VASA program defines an
architecture that integrates third-party storage providers into the vSphere environment, so that
vCenter Server and ESXi hosts can communicate with the storage providers.
To use storage providers, follow these requirements:
n
Make sure that every storage provider you use is certified by VMware and properly deployed. For
information about deploying the storage providers, contact your storage vendor.
n
Make sure that the storage provider is compatible with the vCenter Server and ESXi versions. See
VMware Compatibility Guide.
If your environment contains older versions of storage providers, existing functionality continues to
work. However, to be able to use new features, upgrade your storage provider to a new version.
n
Do not install the VASA provider on the same system as vCenter Server.
Register Storage Providers
To establish a connection between vCenter Server and a storage provider, you must register the storage
provider. Make sure to register a separate storage provider for each host in a cluster.
Note If you use Virtual SAN, the storage providers for Virtual SAN are registered and appear on the list of
storage providers automatically. Virtual SAN does not support manual registration of storage providers. See
the Administering VMware Virtual SAN documentation.
Prerequisites
Verify that the storage provider component is installed on the storage side and obtain its credentials from
your storage administrator.
Procedure
1
Browse to vCenter Server in the vSphere Web Client navigator.
2
Click the Configure tab, and click Storage Providers.
3
Click the Register a new storage provider icon (
4
Type connection information for the storage provider, including the name, URL, and credentials.
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5
Specify the security method.
Action
Description
Direct vCenter Server to the storage
provider certificate
Select the Use storage provider certificate option and specify the
certificate's location.
Use a thumbprint of the storage
provider certificate
If you do not direct vCenter Server to the provider certificate, the certificate
thumbprint is displayed. You can check the thumbprint and approve it.
vCenter Server adds the certificate to the truststore and proceeds with the
connection.
The storage provider adds the vCenter Server certificate to its truststore when vCenter Server first
connects to the provider.
6
Click OK to complete the registration.
vCenter Server registers the storage provider and establishes a secure SSL connection with it.
What to do next
If your storage provider fails to register, see the VMware Knowledge Base article
http://kb.vmware.com/kb/2079087.
View Storage Provider Information
After you register a storage provider component with vCenter Server, the storage provider appears on the
storage providers list. Certain storage providers are self-registered and automatically appear on the list after
you set up the entity they represent, for example, Virtual SAN or I/O filters.
View general storage provider information and details for each storage component.
Procedure
1
Browse to vCenter Server in the vSphere Web Client navigator.
2
Click the Configure tab, and click Storage Providers.
3
In the Storage Providers list, view the storage providers registered with vCenter Server.
The list shows general information including the name of the storage provider, its URL and status,
version of VASA APIs, storage entities the provider represents, and so on.
4
To display additional details, select a specific storage provider or its component from the list.
Note A single storage provider can support storage systems from multiple different vendors.
Unregister Storage Providers
Unregister storage providers that you do not need.
Note You cannot manually unregister storage certain providers supplied by VMware, for example, Virtual
SAN storage providers.
Procedure
1
Browse to vCenter Server in the vSphere Web Client navigator.
2
Click the Configure tab, and click Storage Providers.
3
From the list of storage providers, select the one you want to unregister and click the Unregister the
selected storage provider ( ) icon.
vCenter Server terminates the connection and removes the storage provider from its configuration.
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Update Storage Providers
vCenter Server periodically updates storage data in its database. The updates are partial and reflect only
those storage changes that storage providers communicate to vCenter Server. When needed, you can
perform a full database synchronisation for the selected storage provider.
Procedure
1
Browse to vCenter Server in the vSphere Web Client navigator.
2
Click the Configure tab, and click Storage Providers.
3
From the list, select the storage provider that you want to synchronise with and click the Rescan the
storage provider ( ) icon.
The vSphere Web Client updates the storage data for the provider.
Refresh Storage Provider Certificates
vCenter Server warns you when a certificate assigned to a storage provider is about to expire. You can
refresh the certificate to continue using the provider.
If you fail to refresh the certificate before it expires, vCenter Server discontinues using the provider.
Procedure
1
Browse to vCenter Server in the vSphere Web Client navigator.
2
Click the Configure tab, and click Storage Providers.
3
From the list, select the storage provider and click the Refresh the certificate ( ) icon.
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Working with Virtual Volumes
21
The Virtual Volumes functionality changes the storage management paradigm from managing space inside
datastores to managing abstract storage objects handled by storage arrays. With Virtual Volumes, an
individual virtual machine, not the datastore, becomes a unit of storage management, while storage
hardware gains complete control over virtual disk content, layout, and management.
Historically, vSphere storage management used a datastore-centric approach. With this approach, storage
administrators and vSphere administrators discuss in advance the underlying storage requirements for
virtual machines. The storage administrator then sets up LUNs or NFS shares and presents them to ESXi
hosts. The vSphere administrator creates datastores based on LUNs or NFS, and uses these datastores as
virtual machine storage. Typically, the datastore is the lowest granularity level at which data management
occurs from a storage perspective. However, a single datastore contains multiple virtual machines, which
might have different requirements. With the traditional approach, it is difficult to meet the requirements of
an individual virtual machine.
The Virtual Volumes functionality helps to improve granularity. It helps you to differentiate virtual machine
services on a per application level by offering a new approach to storage management. Rather than
arranging storage around features of a storage system, Virtual Volumes arranges storage around the needs
of individual virtual machines, making storage virtual-machine centric.
Virtual Volumes maps virtual disks and their derivatives, clones, snapshots, and replicas, directly to objects,
called virtual volumes, on a storage system. This mapping allows vSphere to offload intensive storage
operations such as snapshot, cloning, and replication to the storage system.
By creating a volume for each virtual disk, you can set policies at the optimum level. You can decide in
advance what the storage requirements of an application are, and communicate these requirements to the
storage system. The storage system creates an appropriate virtual disk based on these requirements. For
example, if your virtual machine requires an active-active storage array, you no longer must select a
datastore that supports the active-active model. Instead, you create an individual virtual volume that is
automatically placed to the active-active array.
This chapter includes the following topics:
n
“Virtual Volumes Concepts,” on page 240
n
“Virtual Volumes and Storage Protocols,” on page 244
n
“Virtual Volumes Architecture,” on page 246
n
“Virtual Volumes and VMware Certificate Authority,” on page 247
n
“Snapshots and Virtual Volumes,” on page 248
n
“Before You Enable Virtual Volumes,” on page 248
n
“Configure Virtual Volumes,” on page 249
n
“Provision Virtual Machines on Virtual Volumes Datastores,” on page 252
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n
“Virtual Volumes and Replication,” on page 256
n
“Best Practices for Working with vSphere Virtual Volumes,” on page 260
Virtual Volumes Concepts
With Virtual Volumes, abstract storage containers replace traditional storage volumes based on LUNs or
NFS shares. In vCenter Server, the storage containers are represented by Virtual Volumes datastores. Virtual
Volumes datastores store virtual volumes, objects that encapsulate virtual machine files.
Watch the video to learn more about different components of the Virtual Volumes functionality.
Virtual Volumes Part 1: Concepts
(http://link.brightcove.com/services/player/bcpid2296383276001?
bctid=ref:video_vvols_part1_concepts)
n
Virtual Volumes on page 240
Virtual volumes are encapsulations of virtual machine files, virtual disks, and their derivatives.
n
Virtual Volumes and Storage Providers on page 241
A Virtual Volumes storage provider, also called a VASA provider, is a software component that acts as
a storage awareness service for vSphere. The provider mediates out-of-band communication between
vCenter Server and ESXi hosts on one side and a storage system on the other.
n
Storage Containers on page 242
Unlike traditional LUN and NFS-based storage, the Virtual Volumes functionality does not require
preconfigured volumes on a storage side. Instead, Virtual Volumes uses a storage container. It is a pool
of raw storage capacity or an aggregation of storage capabilities that a storage system can provide to
virtual volumes.
n
Protocol Endpoints on page 242
Although storage systems manage all aspects of virtual volumes, ESXi hosts have no direct access to
virtual volumes on the storage side. Instead, ESXi hosts use a logical I/O proxy, called the protocol
endpoint, to communicate with virtual volumes and virtual disk files that virtual volumes
encapsulate. ESXi uses protocol endpoints to establish a data path on demand from virtual machines
to their respective virtual volumes.
n
Binding and Unbinding Virtual Volumes to Protocol Endpoints on page 243
At the time of creation, a virtual volume is a passive entity and is not immediately ready for I/O. To
access the virtual volume, ESXi or vCenter Server send a bind request.
n
Virtual Volumes Datastores on page 243
A Virtual Volumes (VVol) datastore represents a storage container in vCenter Server and the
vSphere Web Client.
n
Virtual Volumes and VM Storage Policies on page 244
A virtual machine that runs on a Virtual Volumes datastore requires a VM storage policy.
Virtual Volumes
Virtual volumes are encapsulations of virtual machine files, virtual disks, and their derivatives.
Virtual volumes are stored natively inside a storage system that is connected to your ESXi hosts through
Ethernet or SAN. They are exported as objects by a compliant storage system and are managed entirely by
hardware on the storage side. Typically, a unique GUID identifies a virtual volume. Virtual volumes are not
preprovisioned, but created automatically when you perform virtual machine management operations.
These operations include a VM creation, cloning, and snapshotting. ESXi and vCenter Server associate one
or more virtual volumes to a virtual machine.
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The system creates the following types of virtual volumes for the core elements that make up the virtual
machine:
n
Data-VVol. A data virtual volume that corresponds directly to each virtual disk .vmdk file. As virtual
disk files on traditional datastores, virtual volumes are presented to virtual machines as SCSI disks.
Data-VVols can be either thick or thin provisioned.
n
Config-VVol. A configuration virtual volume, or a home directory, represents a small directory that
contains metadata files for a virtual machine. The files include a .vmx file, descriptor files for virtual
disks, log files, and so forth. The configuration virtual volume is formatted with a file system. When
ESXi uses the SCSI protocol to connect to storage, configuration virtual volumes are formatted with
VMFS. With NFS protocol, configuration virtual volumes are presented as an NFS directory. Typically, it
is thin provisioned.
n
Swap-VVol. Created when a VM is first powered on. It is a virtual volume to hold copies of VM
memory pages that cannot be retained in memory. Its size is determined by the VM’s memory size. It is
thick provisioned by default.
n
Snapshot-VVol. A virtual memory volume to hold the contents of virtual machine memory for a
snapshot. Thick provisioned.
n
Other. A virtual volume for specific features. For example, a digest virtual volume is created for
Content-Based Read Cache (CBRC).
Typically, a VM creates a minimum of three virtual volumes, data-VVol, config-VVol, and swap-VVol. The
maximum depends on how many virtual disks and snapshots reside on the VM.
For example, the following SQL server has six virtual volumes:
n
Config-VVol
n
Data-VVol for the operating system
n
Data-VVol for the database
n
Data-VVol for the log
n
Swap-VVol when powered on
n
Snapshot-VVol
By using different virtual volumes for different VM components, you can apply and manipulate storage
policies at the finest granularity level. For example, a virtual volume that contains a virtual disk can have a
richer set of data services than the virtual volume for the VM boot disk. Similarly, a snapshot virtual volume
can use a different storage tier compared to a current virtual volume.
Virtual Volumes and Storage Providers
A Virtual Volumes storage provider, also called a VASA provider, is a software component that acts as a
storage awareness service for vSphere. The provider mediates out-of-band communication between
vCenter Server and ESXi hosts on one side and a storage system on the other.
The storage provider is implemented through VMware APIs for Storage Awareness (VASA) and is used to
manage all aspects of Virtual Volumes storage. The storage provider integrates with the Storage Monitoring
Service (SMS), shipped with vSphere, to communicate with vCenter Server and ESXi hosts.
The storage provider delivers information from the underlying storage container. The storage container
capabilities appear in vCenter Server and the vSphere Web Client. Then, in turn, the storage provider
communicates virtual machine storage requirements, which you can define in the form of a storage policy, to
the storage layer. This integration process ensures that a virtual volume created in the storage layer meets
the requirements outlined in the policy.
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Typically, vendors are responsible for supplying storage providers that can integrate with vSphere and
provide support to Virtual Volumes. Every storage provider must be certified by VMware and properly
deployed. For information about deploying and upgrading the Virtual Volumes storage provider to a
version compatible with current ESXi release, contact your storage vendor.
After you deploy the storage provider, you must register it in vCenter Server, so that it can communicate
with vSphere through the SMS.
Storage Containers
Unlike traditional LUN and NFS-based storage, the Virtual Volumes functionality does not require
preconfigured volumes on a storage side. Instead, Virtual Volumes uses a storage container. It is a pool of
raw storage capacity or an aggregation of storage capabilities that a storage system can provide to virtual
volumes.
A storage container is a part of the logical storage fabric and is a logical unit of the underlying hardware.
The storage container logically groups virtual volumes based on management and administrative needs. For
example, the storage container can contain all virtual volumes created for a tenant in a multitenant
deployment, or a department in an enterprise deployment. Each storage container serves as a virtual volume
store and virtual volumes are allocated out of the storage container capacity.
Typically, a storage administrator on the storage side defines storage containers. The number of storage
containers, their capacity, and their size depend on a vendor-specific implementation. At least one container
for each storage system is required.
Note A single storage container cannot span different physical arrays.
After you register a storage provider associated with the storage system, vCenter Server discovers all
configured storage containers along with their storage capability profiles, protocol endpoints, and other
attributes. A single storage container can export multiple capability profiles. As a result, virtual machines
with diverse needs and different storage policy settings can be a part of the same storage container.
Initially, all discovered storage containers are not connected to any specific host, and you cannot see them in
the vSphere Web Client. To mount a storage container, you must map it to a Virtual Volumes datastore.
Protocol Endpoints
Although storage systems manage all aspects of virtual volumes, ESXi hosts have no direct access to virtual
volumes on the storage side. Instead, ESXi hosts use a logical I/O proxy, called the protocol endpoint, to
communicate with virtual volumes and virtual disk files that virtual volumes encapsulate. ESXi uses
protocol endpoints to establish a data path on demand from virtual machines to their respective virtual
volumes.
Each virtual volume is bound to a specific protocol endpoint. When a virtual machine on the host performs
an I/O operation, the protocol endpoint directs the I/O to the appropriate virtual volume. Typically, a storage
system requires just a few protocol endpoints. A single protocol endpoint can connect to hundreds or
thousands of virtual volumes.
On the storage side, a storage administrator configures protocol endpoints, one or several per storage
container. The protocol endpoints are a part of the physical storage fabric. The storage system exports the
protocol endpoints with associated storage containers through the storage provider. After you map the
storage container to a Virtual Volumes datastore, the ESXi host discovers the protocol endpoints and they
become visible in the vSphere Web Client. The protocol endpoints can also be discovered during a storage
rescan. Multiple hosts can discover and mount the protocol endpoints.
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In the vSphere Web Client, the list of available protocol endpoints looks similar to the host storage devices
list. Different storage transports can be used to expose the protocol endpoints to ESXi. When the SCSI-based
transport is used, the protocol endpoint represents a proxy LUN defined by a T10-based LUN WWN. For
the NFS protocol, the protocol endpoint is a mount-point, such as an IP address (or DNS name) and a share
name. You can configure multipathing on the SCSI-based protocol endpoint, but not on the NFS-based
protocol endpoint. No matter which protocol you use, the storage array can provide multiple protocol
endpoints for availability purposes.
Protocol endpoints are managed per array. ESXi and vCenter Server assume that all protocol endpoints
reported for an array are associated with all containers on that array. For example, if an array has two
containers and three protocol endpoints, ESXi assumes that virtual volumes on both containers can be
bound to all three protocol points.
Binding and Unbinding Virtual Volumes to Protocol Endpoints
At the time of creation, a virtual volume is a passive entity and is not immediately ready for I/O. To access
the virtual volume, ESXi or vCenter Server send a bind request.
The storage system replies with a protocol endpoint ID that becomes an access point to the virtual volume.
The protocol endpoint accepts all I/O requests to the virtual volume. This binding exists until ESXi sends an
unbind request for the virtual volume.
For later bind requests on the same virtual volume, the storage system can return different protocol
endpoint IDs.
When receiving concurrent bind requests to a virtual volume from multiple ESXi hosts, the storage system
can return the same or different endpoint bindings to each requesting ESXi host. In other words, the storage
system can bind different concurrent hosts to the same virtual volume through different endpoints.
The unbind operation removes the I/O access point for the virtual volume. The storage system might unbind
the virtual volume from its protocol endpoint immediately, or after a delay, or take some other action. A
bound virtual volume cannot be deleted until it is unbound.
Virtual Volumes Datastores
A Virtual Volumes (VVol) datastore represents a storage container in vCenter Server and the
vSphere Web Client.
After vCenter Server discovers storage containers exported by storage systems, you must mount them as
Virtual Volumes datastores to be able to use them. The Virtual Volumes datastores are not formatted in a
traditional way. You must still create them because all vSphere functionalities, including FT, HA, DRS, and
so on, require the datastore construct to function properly.
You use the datastore creation wizard in the vSphere Web Client to map a storage container to a Virtual
Volumes datastore. The Virtual Volumes datastore that you create corresponds directly to the specific
storage container. The datastore represents the container in vCenter Server and the vSphere Web Client.
From a vSphere administrator prospective, the Virtual Volumes datastore is similar to any other datastore
and is used to hold virtual machines. Like other datastores, the Virtual Volumes datastore can be browsed
and lists virtual volumes by virtual machine name. Like traditional datastores, the Virtual Volumes
datastore supports unmounting and mounting. However, such operations as upgrade and resize are not
applicable to the Virtual Volumes datastore. The Virtual Volumes datastore capacity is configurable by the
storage administrator outside of vSphere.
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You can use the Virtual Volumes datastores with traditional VMFS and NFS datastores and with Virtual
SAN.
Note The size of a virtual volume must be a multiple of 1 MB, with a minimum size of 1 MB. As a result,
all virtual disks that you provision on a Virtual Volumes datastore must be an even multiple of 1 MB. If the
virtual disk you migrate to the Virtual Volumes datastore is not an even multiple of 1 MB, extend the disk to
the nearest even multiple of 1 MB.
Virtual Volumes and VM Storage Policies
A virtual machine that runs on a Virtual Volumes datastore requires a VM storage policy.
A VM storage policy is a set of rules that contains placement and quality-of-service requirements for a
virtual machine. The policy enforces appropriate placement of the virtual machine within Virtual Volumes
storage and guarantees that storage can satisfy virtual machine requirements.
You use the VM Storage Policies interface to create a Virtual Volumes storage policy. When you assign the
new policy to the virtual machine, the policy enforces that the Virtual Volumes storage meets the
requirements.
If you do not create the VM storage policy compatible with the Virtual Volumes datastore, the system uses
default No Requirements policy. The No Requirements policy is a generic Virtual Volumes policy that
contains no rules or storage specifications. The policy allows Virtual Volumes storage arrays to determine
the most appropriate placement for the VM objects.
Virtual Volumes and Storage Protocols
A virtual volumes-based storage system provides protocol endpoints that are discoverable on the physical
storage fabric. ESXi hosts use the protocol endpoints to connect to virtual volumes on the storage. Operation
of the protocol endpoints depends on storage protocols that expose the endpoints to ESXi hosts.
Virtual Volumes supports NFS version 3, iSCSI, Fibre Channel, and FCoE.
No matter which storage protocol is used, protocol endpoints provide uniform access to both SAN and NAS
storage. A virtual volume, like a file on other traditional datastore, is presented to a virtual machine as a
SCSI disk.
Note A storage container is dedicated to SCSI or NAS and cannot be shared across those protocol types.
An array can present one storage container with SCSI protocol endpoints and a different container with NFS
protocol endpoints. The container cannot use a combination of SCSI and NFS protocol endpoints.
Virtual Volumes and SCSI-Based Transports
On disk arrays, virtual volumes support Fibre Channel, FCoE, and iSCSI protocols.
When the SCSI-based protocol is used, the protocol endpoint represents a proxy LUN defined by a T10based LUN WWN.
As any block-based LUNs, the protocol endpoints are discovered using standard LUN discovery
commands. The ESXi host periodically rescans for new devices and asynchronously discovers block-based
protocol endpoints. The protocol endpoint can be accessible by multiple paths. Traffic on these paths follows
well-known path selection policies, as is typical for LUNs.
On SCSI-based disk arrays at VM creation time, ESXi makes a virtual volume and formats it as VMFS. This
small virtual volume stores all VM metadata files and is called the config-VVol. The config-VVol functions as
a VM storage locator for vSphere.
Virtual volumes on disk arrays support the same set of SCSI commands as VMFS and use ATS as a locking
mechanism.
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Virtual Volumes and NFS Transports
With NAS storage, a protocol endpoint is an NFS share that the ESXi host mounts using IP address or DNS
name and a share name. Virtual Volumes supports NFS version 3 to access NAS storage.
No matter which version you use, a storage array can provide multiple protocol endpoints for availability
purposes.
Virtual volumes on NAS devices support the same NFS Remote Procedure Calls (RPCs) that ESXi hosts use
when connecting to NFS mount points.
On NAS devices, a config-VVol is a directory subtree that corresponds to a config-VVolID. The config-VVol
must support directories and other operations that are necessary for NFS.
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Virtual Volumes Architecture
An architectural diagram provides an overview of how all components of the Virtual Volumes functionality
interact with each other.
Data center
VM storage policies
Bronze
VM
VM
Silver
Gold
VM
VM
Storage
Monitoring
Service
VM
VM
VMware vSphere
(corresponds to
storage container 1)
Virtual
datastore 1
Virtual
datastore 2
(corresponds to
storage container 2)
VASA APIs
Fibre Channel, FCoE,
iSCSI, NFS
Protocol endpoints
Virtual
volume
Virtual
volume
Virtual
volume
Virtual
volume
Storage container 1
Virtual
volume
Virtual
volume
Storage container 2
VASA
provider
Storage array
Virtual volumes are objects exported by a compliant storage system and typically correspond one-to-one
with a virtual machine disk and other VM-related files. A virtual volume is created and manipulated out-ofband, not in the data path, by a VASA provider.
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A VASA provider, or a storage provider, is developed through vSphere APIs for Storage Awareness. The
storage provider enables communication between the ESXi hosts, vCenter Server, and the
vSphere Web Client on one side, and the storage system on the other. The VASA provider runs on the
storage side and integrates with the vSphere Storage Monitoring Service (SMS) to manage all aspects of
Virtual Volumes storage. The VASA provider maps virtual disk objects and their derivatives, such as clones,
snapshots, and replicas, directly to the virtual volumes on the storage system.
The ESXi hosts have no direct access to the virtual volumes storage. Instead, the hosts access the virtual
volumes through an intermediate point in the data path, called the protocol endpoint. The protocol
endpoints establish a data path on demand from the virtual machines to their respective virtual volumes.
The protocol endpoints serve as a gateway for direct in-band I/O between ESXi hosts and the storage
system. ESXi can use Fibre Channel, FCoE, iSCSI, and NFS protocols for in-band communication.
The virtual volumes reside inside storage containers that logically represent a pool of physical disks on the
storage system. On the vCenter Server and ESXi side, storage containers are presented as Virtual Volumes
datastores. A single storage container can export multiple storage capability sets and provide different levels
of service to different virtual volumes.
Watch the video for information about Virtual Volumes architecture.
Virtual Volumes Part 2: Architecture
(http://link.brightcove.com/services/player/bcpid2296383276001?
bctid=ref:video_vvols_part2_architecture)
Virtual Volumes and VMware Certificate Authority
vSphere includes the VMware Certificate Authority (VMCA). By default, the VMCA creates all internal
certificates used in vSphere environment. It generates certificates for newly added ESXi hosts and storage
VASA providers that manage or represent Virtual Volumes storage systems.
Communication with the VASA provider is protected by SSL certificates. These certificates can come from
the VASA provider or from the VMCA.
n
Certificates can be directly provided by the VASA provider for long-term use. They can be either selfgenerated and self-signed, or derived from an external Certificate Authority.
n
Certificates can be generated by the VMCA for use by the VASA provider.
When a host or VASA provider is registered, VMCA follows these steps automatically, without involvement
from the vSphere administrator.
1
When a VASA provider is first added to the vCenter Server storage management service (SMS), it
produces a self-signed certificate.
2
After verifying the certificate, the SMS requests a Certificate Signing Request (CSR) from the VASA
provider.
3
After receiving and validating the CSR, the SMS presents it to the VMCA on behalf of the VASA
provider, requesting a CA signed certificate.
The VMCA can be configured to function as a standalone CA, or as a subordinate to an enterprise CA.
If you set up the VMCA as a subordinate CA, the VMCA signs the CSR with the full chain.
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The signed certificate with the root certificate is passed to the VASA provider. The VASA provider can
authenticate all future secure connections originating from the SMS on vCenter Server and on ESXi
hosts.
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Snapshots and Virtual Volumes
Snapshots preserve the state and data of a virtual machine at the time you take the snapshot. Snapshots are
useful when you must revert repeatedly to the same virtual machine state, but you do not want to create
multiple virtual machines. Virtual volumes snapshots serve many purposes. For example, to create a
quiesced copy for backup or archival purposes, create a test and rollback environment for applications,
instantly provision application images, and so on.
In Virtual Volumes environment, snapshots are managed by ESXi and vCenter Server, but are performed by
the storage array.
Each snapshot creates an extra virtual volume object, snapshot, or memory, virtual volume, that holds the
contents of virtual machine memory. Original VM data is copied to this object, and it remains read-only,
which prevents the guest operating system from writing to snapshot. You cannot resize the snapshot virtual
volume. And it can be read only when the VM is reverted to a snapshot. Typically, when you replicate the
VM, its snapshot virtual volume is also replicated.
Storage Container
Snap-001VVol
Base VVol
Snap-002 VVol
Read Only
Read Write
Read Only
The base virtual volume remains active, or read-write. When another snapshot is created, it preserves the
new state and data of the virtual machine at the time you take the snapshot.
Deleting snapshots leaves the base virtual volume that represents the most current state of the virtual
machine. Snapshot virtual volumes are discarded. Unlike snapshots on the traditional datastores, virtual
volumes snapshots do not need to commit their contents to the base virtual volume.
Storage Container
Base VVol
Read Write
For information about creating and managing snapshots, see the vSphere Virtual Machine Administration
documentation.
Before You Enable Virtual Volumes
To work with Virtual Volumes, you must make sure that your storage and vSphere environment are set up
correctly.
Prepare Storage System for Virtual Volumes
To prepare your storage system environment for Virtual Volumes, follow these guidelines. For additional
information, contact your storage vendor.
n
248
The storage system or storage array that you use must support Virtual Volumes and integrate with the
vSphere components through vSphere APIs for Storage Awareness (VASA). The storage array must
support thin provisioning and snapshotting.
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n
The Virtual Volumes storage provider must be deployed.
n
The following components must be configured on the storage side:
n
Protocol endpoints
n
Storage containers
n
Storage profiles
n
Replication configurations if you plan to use Virtual Volumes with replication. See “Requirements
for Replication with Virtual Volumes,” on page 256.
Prepare vSphere Environment
n
Make sure to follow appropriate setup guidelines for the type of storage you use, Fibre Channel, FCoE,
iSCSI, or NFS. If necessary, install and configure storage adapters on your ESXi hosts.
n
n
If you use iSCSI, activate the software iSCSI adapters on your ESXi hosts. Configure Dynamic
Discovery and enter the IP address of your Virtual Volumes storage system. See “Configure the
Software iSCSI Adapter,” on page 78.
Synchronize all components in the storage array with vCenter Server and all ESXi hosts. Use Network
Time Protocol (NTP) to do this synchronization.
For more information, contact your vendor and see VMware Compatibility Guide
Synchronize vSphere Storage Environment with a Network Time Server
If you use Virtual Volumes, configure Network Time Protocol (NTP) to make sure all ESXi hosts on the
vSphere network are synchronized.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, select Time Configuration.
4
Click Edit and set up the NTP server.
5
a
Select Use Network Time Protocol (Enable NTP client).
b
Set the NTP Service Startup Policy.
c
Enter the IP addresses of the NTP server to synchronize with.
d
Click Start or Restart in the NTP Service Status section.
Click OK.
The host synchronizes with the NTP server.
Configure Virtual Volumes
To configure your Virtual Volumes environment, follow several steps.
Prerequisites
Follow guidelines in “Before You Enable Virtual Volumes,” on page 248.
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Procedure
1
Register Storage Providers for Virtual Volumes on page 250
Your Virtual Volumes environment must include storage providers, also called VASA providers.
Typically, third-party vendors develop storage providers through the VMware APIs for Storage
Awareness (VASA). Storage providers facilitate communication between vSphere and the storage side.
You must register the storage provider in vCenter Server to be able to work with Virtual Volumes.
2
Create a Virtual Volumes Datastore on page 251
You use the New Datastore wizard to create a Virtual Volumes datastore.
3
Review and Manage Protocol Endpoints on page 251
ESXi hosts use a logical I/O proxy, called protocol endpoint, to communicate with virtual volumes and
virtual disk files that virtual volumes encapsulate. Protocol endpoints are exported, along with
associated storage containers, by the storage system through a storage provider. Protocol endpoints
become visible in the vSphere Web Client after you map a storage container to a Virtual Volumes
datastore. You can review properties of protocol endpoints and modify specific settings.
4
(Optional) Change the Path Selection Policy for a Protocol Endpoint on page 252
If your ESXi host uses SCSI-based transport to communicate with protocol endpoints representing a
storage array, you can modify default multipathing policies assigned to protocol endpoints. Use the
Edit Multipathing Policies dialog box to change a path selection policy.
What to do next
You can now provision virtual machines on the Virtual Volumes datastore. For information on creating
virtual machines, see the vSphere Virtual Machine Administration documentation.
For troubleshooting information, see the vSphere Troubleshooting documentation.
Register Storage Providers for Virtual Volumes
Your Virtual Volumes environment must include storage providers, also called VASA providers. Typically,
third-party vendors develop storage providers through the VMware APIs for Storage Awareness (VASA).
Storage providers facilitate communication between vSphere and the storage side. You must register the
storage provider in vCenter Server to be able to work with Virtual Volumes.
After registration, the Virtual Volumes provider communicates with vCenter Server. The provider reports
characteristics of underlying storage and data services, such as replication, that the storage system provides.
The characteristics appear in the VM Storage Policies interface and can be used to create a VM storage policy
compatible with the Virtual Volumes datastore. After you apply this storage policy to a virtual machine, the
policy is pushed to Virtual Volumes storage. The policy enforces optimal placement of the virtual machine
within Virtual Volumes storage and guarantees that storage can satisfy virtual machine requirements. If
your storage provides extra services, such as caching or replication, the policy enables these services for the
virtual machine.
Prerequisites
Verify that an appropriate version of the Virtual Volumes storage provider is installed on the storage side.
Obtain credentials of the storage provider.
Procedure
250
1
Browse to vCenter Server in the vSphere Web Client navigator.
2
Click the Configure tab, and click Storage Providers.
3
Click the Register a new storage provider icon (
4
Type connection information for the storage provider, including the name, URL, and credentials.
).
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Specify the security method.
Action
Description
Direct vCenter Server to the storage
provider certificate
Select the Use storage provider certificate option and specify the
certificate's location.
Use a thumbprint of the storage
provider certificate
If you do not direct vCenter Server to the provider certificate, the certificate
thumbprint is displayed. You can check the thumbprint and approve it.
vCenter Server adds the certificate to the truststore and proceeds with the
connection.
The storage provider adds the vCenter Server certificate to its truststore when vCenter Server first
connects to the provider.
6
To complete the registration, click OK.
vCenter Server discovers and registers the Virtual Volumes storage provider.
Create a Virtual Volumes Datastore
You use the New Datastore wizard to create a Virtual Volumes datastore.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the New Datastore icon.
3
Specify the placement location for the datastore.
4
Select VVol as the datastore type.
5
From the list of storage containers, select a backing storage container and type the datastore name.
Make sure to use the name that does not duplicate another datastore name in your data center
environment.
If you mount the same Virtual Volumes datastore to several hosts, the name of the datastore must be
consistent across all hosts.
6
Select the hosts that require access to the datastore.
7
Review the configuration options and click Finish.
What to do next
After you create the Virtual Volumes datastore, you can perform such datastore operations as renaming the
datastore, browsing datastore files, unmounting the datastore, and so on.
You cannot add the Virtual Volumes datastore to a datastore cluster.
Review and Manage Protocol Endpoints
ESXi hosts use a logical I/O proxy, called protocol endpoint, to communicate with virtual volumes and
virtual disk files that virtual volumes encapsulate. Protocol endpoints are exported, along with associated
storage containers, by the storage system through a storage provider. Protocol endpoints become visible in
the vSphere Web Client after you map a storage container to a Virtual Volumes datastore. You can review
properties of protocol endpoints and modify specific settings.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
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3
Under Storage, click Protocol Endpoints.
4
To view details for a specific item, select this item from the list.
5
Use tabs under Protocol Endpoint Details to access additional information and modify properties for
the selected protocol endpoint.
Tab
Description
Properties
View the item properties and characteristics. For SCSI (block) items, view
and edit multipathing policies.
Paths (SCSI protocol endpoints
only)
Display paths available for the protocol endpoint. Disable or enable a
selected path. Change the Path Selection Policy.
Datastores
Display a corresponding Virtual Volumes datastore. Perform datastore
management operations.
(Optional) Change the Path Selection Policy for a Protocol Endpoint
If your ESXi host uses SCSI-based transport to communicate with protocol endpoints representing a storage
array, you can modify default multipathing policies assigned to protocol endpoints. Use the Edit
Multipathing Policies dialog box to change a path selection policy.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under Storage, click Protocol Endpoints.
4
Select the protocol endpoint whose paths you want to change and click the Properties tab.
5
Under Multipathing Policies, click Edit Multipathing.
6
Select a path policy.
The path policies available for your selection depend on the storage vendor support.
n
Fixed (VMware)
n
Most Recently Used (VMware)
n
Round Robin (VMware)
7
For the fixed policy, specify the preferred path.
8
Click OK to save your settings and exit the dialog box.
Provision Virtual Machines on Virtual Volumes Datastores
You can provision virtual machines on a Virtual Volumes datastore.
Note All virtual disks that you provision on a Virtual Volumes datastore must be an even multiple of 1
MB.
A virtual machine that runs on a Virtual Volumes datastore requires an appropriate VM storage policy.
After you provision the virtual machine, you can perform typical VM management tasks. For information,
see the vSphere Virtual Machine Administration documentation.
For troubleshooting information, see the vSphere Troubleshooting documentation.
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Procedure
1
Define a VM Storage Policy for Virtual Volumes on page 253
VMware provides a default No Requirements storage policy for Virtual Volumes. If you need, you can
create a custom storage policy compatible with Virtual Volumes.
2
Assign the Virtual Volumes Storage Policy to Virtual Machines on page 254
To guarantee that the Virtual Volumes datastore fulfills specific storage requirements when allocating
a virtual machine, associate the Virtual Volumes storage policy with the virtual machine.
3
Change Default Storage Policy for a Virtual Volumes Datastore on page 255
For virtual machines provisioned on Virtual Volumes datastores, VMware provides a default No
Requirements policy. You cannot edit this policy, but you can designate a newly created policy as
default.
Define a VM Storage Policy for Virtual Volumes
VMware provides a default No Requirements storage policy for Virtual Volumes. If you need, you can
create a custom storage policy compatible with Virtual Volumes.
Prerequisites
n
Verify that the Virtual Volumes storage provider is available and active. See “Register Storage Providers
for Virtual Volumes,” on page 250.
n
Make sure that the VM Storage Policies interface is populated with information about storage entities
and data services that are available in your storage environment. See “Populating the VM Storage
Policies Interface,” on page 213.
n
Define appropriate storage policy components. See “Create Storage Policy Components,” on page 221.
n
Required privileges: VM storage policies.Update and VM storage policies.View.
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the VM Storage Policies tab.
3
Click the Create a New VM Storage Policy icon.
4
Select the vCenter Server instance.
5
Type a name and a description for the storage policy.
6
On the Rule Set page, define placement rules.
a
From the Storage Type drop-down menu, select a target storage entity, for example, Virtual
Volumes.
b
From theAdd rule drop-down menu, select a capability and specify its value.
For example, you can specify the number of read operations per second for the Virtual Volumes
objects. You can include as many rules as you need for the selected storage entity. Verify that the
values you provide are within the range of values that the storage resource advertises.
c
(Optional) To fine-tune your placement request further, add a tag-based rule.
Tag-based rules can include or exclude specific placement criteria. For example, you can exclude
datastores with the Palo Alto tag from the list of your target Virtual Volumes datastores.
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7
(Optional) Select data services to include in the VM storage policy.
The data services that you reference on the Rule Set page are provided by the storage. The VM storage
policy that references the data services, requests them for the virtual machine.
a
Click the Add component (
for example, Replication.
b
Define rules for the data service category by specifying an appropriate provider and values for the
rules. Or select the data service from the list of predefined components.
Option
Component Name
c
) icon and select a data service category from the drop-down menu,
Description
This option is available if you have predefined storage policy
components in your database. If you know which component to use,
select it from the list to add to the VM storage policy.
See all
Review all component available for the category. To include a specific
component, select it from the list and click OK.
Custom
Define custom rules for the data service category by specifying an
appropriate provider and values for the rules.
Add more components to request other data services.
You can use only one component from the same category, for example caching, per a set of common
or regular rules.
8
Complete the creation of the storage policy and click Finish.
The new VM storage policy compatible with Virtual Volumes appears on the list.
What to do next
You can now associate this policy with a virtual machine, or designate the policy as default.
Assign the Virtual Volumes Storage Policy to Virtual Machines
To guarantee that the Virtual Volumes datastore fulfills specific storage requirements when allocating a
virtual machine, associate the Virtual Volumes storage policy with the virtual machine.
You can assign the Virtual Volumes storage policy during an initial deployment of a virtual machine, or
when performing other virtual machine operations, such as cloning or migrating. This topic describes how
to assign the Virtual Volumes storage policy when you create a new virtual machine. For information about
other VM provisioning methods, see the vSphere Virtual Machine Administration documentation.
You can apply the same storage policy to the virtual machine configuration file and all its virtual disks. If
storage requirements for your virtual disks and the configuration file are different, you can associate
different storage policies with the VM configuration file and the selected virtual disks.
Procedure
1
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In the vSphere Web Client, start the virtual machine provisioning process and follow appropriate steps.
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2
Assign the same storage policy to all virtual machine files and disks.
a
On the Select Storage page, select the storage policy compatible with Virtual Volumes, for example
VVols Silver, from the VM Storage Policy drop-down menu.
b
Select the Virtual Volumes datastore from the list of available datastores.
c
If you use the replication service with Virtual Volumes, specify the replication group.
Replication groups indicate which VMs and virtual disks must be replicated together to a target
site.
Option
Description
Preconfigured replication group
Replication groups that are configured in advance on the storage side.
vCenter Server and ESXi discover the replication groups, but do not
manage their life cycle.
Automatic replication group
Virtual Volumes creates a replication group and assigns all VM objects
to this group.
The datastore becomes the destination storage resource for the virtual machine configuration file and all
virtual disks.
3
Change the storage policy for the virtual disk.
Use this option if requirements for storage placement are different for virtual disks.
4
a
On the Customize Hardware page, expand the New hard disk pane.
b
From the VM storage policy drop-down menu, select the appropriate storage policy, for example
VVols Gold, that you want to assign to the virtual disk.
c
For replication, specify or modify the replication group. If you use the automatic replication group
for the virtual machine, you cannot change it to the preconfigured group for the virtual disk.
Complete the virtual machine provisioning process.
After you create the virtual machine, the Summary tab displays the assigned storage policies and their
compliance status.
What to do next
If storage placement requirements for the configuration file or the virtual disks change, you can later modify
the virtual policy assignment. See “Change Storage Policy Assignment for Virtual Machine Files and Disks,”
on page 228.
Change Default Storage Policy for a Virtual Volumes Datastore
For virtual machines provisioned on Virtual Volumes datastores, VMware provides a default No
Requirements policy. You cannot edit this policy, but you can designate a newly created policy as default.
Prerequisites
Create a storage policy compatible with Virtual Volumes.
Procedure
1
Browse to the Virtual Volumes datastore whose default storage policy you want to change.
2
Click the Configure tab.
3
Under Settings, click General.
4
Click Edit in the Default Storage Policy pane.
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5
From the list of available storage policies, select a policy to designate as the default and click OK.
The selected storage policy becomes the default policy for the Virtual Volumes datastore. vSphere assigns
this policy to any virtual machine objects that you provision on the Virtual Volumes datastore when no
other policy is explicitly selected.
Virtual Volumes and Replication
Virtual Volumes supports replication and disaster recovery. Replication with Virtual Volumes allows you to
off-load replication of virtual machines to your storage array and use full replication capabilities of the array.
You can replicate a single VM object, such as a virtual disk, or group several VM objects or virtual machines
to replicate them as a single unit.
Array-based replication is policy driven. After you configure your Virtual Volumes storage for replication,
information about replication capabilities and replication groups, delivered from the array by the storage
provider, shows in the VM Storage Policy interface of vCenter Server.
You use the VM storage policy to describe replication requirements for your virtual machines. The
parameters that you specify in the storage policy depend on how your array implements replication. For
example, your VM storage policy might include such parameters as the replication schedule, replication
frequency, or recovery point objective (RPO). The policy might also indicate the replication target, a
secondary site where your virtual machines are replicated, or specify whether replicas must be deleted.
By assigning the replication policy during VM provisioning, you request replication services for your virtual
machine. After that, the array takes over the management of all replication schedules and processes.
ESXi Host
ESXi Host
Array based
replication
config swap
data
DB1
DB2
DB3
config swap
data
DB1
Virtual Volumes
Virtual Volumes
Site 1
Site 2
DB2
DB3
Requirements for Replication with Virtual Volumes
When you enable Virtual Volumes with replication, in addition to general Virtual Volumes requirements,
your environment must satisfy several specific prerequisites.
For general Virtual Volumes requirements, see “Before You Enable Virtual Volumes,” on page 248.
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Storage Requirements
Implementation of Virtual Volumes replication depends on your array and might be different for storage
vendors. Generally, the following requirements apply to all vendors.
n
The storage arrays that you use to implement replication must be compatible with Virtual Volumes.
n
The arrays must integrate with the version of the storage (VASA) provider compatible with Virtual
Volumes replication.
n
The storage arrays must be replication capable and configured to use vendor-provided replication
mechanisms. Typical configurations usually involve one or two replication targets. Any required
configurations, such as pairing of the replicated site and the target site, must be also performed on the
storage side.
n
When applicable, replication groups and fault domains for Virtual Volumes must be preconfigured on
the storage side.
For more information, contact your vendor and see VMware Compatibility Guide.
vSphere Requirements
n
Use the vCenter Server and ESXi versions that support Virtual Volumes storage replication.
vCenter Server and ESXi hosts that are older than 6.5 release do not support replicated Virtual Volumes
storage. Any attempts to create a replicated VM on an incompatible host fail with an error. For
information, see VMware Compatibility Guide.
n
If you plan to migrate a virtual machine, make sure that target resources, such as the ESXi hosts and
Virtual Volumes datastores, support storage replication.
Virtual Volumes and Replication Groups
When your storage offers replication services, in addition to storage containers and protocol endpoints, your
storage administrator can configure replication groups on the storage side.
vCenter Server and ESXi can discover replication groups, but do not manage their life cycle. Replication
groups, also called consistency groups, indicate which VMs and virtual disks must be replicated together to
a target site. You can assign components of the same virtual machine, such as the VM configuration file and
virtual disks, to different preconfigured replication groups. Or exclude certain VM components from
replication.
Storage Container
Replication Group A
Replication Group B
If no preconfigured groups are available, Virtual Volumes can use an automatic method. With the automatic
method, Virtual Volumes creates a replication group on demand and associates this group with a Virtual
Volumes object being provisioned. If you use the automatic replication group, all components of a virtual
machine are assigned to the group. You cannot mix preconfigured and automatic replication groups for
components of the same virtual machine.
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Virtual Volumes and Fault Domains
In the context of Virtual Volumes replication, fault domains define how specific replication groups must be
combined when being replicated from a source to a target site.
Fault domains are configured and reported by the storage array, and are not exposed in the
vSphere Web Client. The Storage Policy Based Management (SPBM) mechanism discovers fault domains
and uses them for validation purposes during virtual machine creation.
For example, provision a VM with two disks, one associated with replication group Anaheim:B, the second
associated with replication group Anaheim:C. SPBM validates the provisioning because both disks are
replicated to the same target fault domains.
Source
Target
Fault Domain: “Anaheim”
Fault Domain: “Boulder”
Repl. Group:”Anaheim:A”
Repl. Group:”Boulder:A”
Repl. Group:”Anaheim:B”
Repl. Group:”Boulder:B”
Repl. Group:”Anaheim:C”
Repl. Group:”Boulder:C”
Repl. Group:”Anaheim:D”
Fault Domain: “New-York”
Repl. Group:”Anaheim:E”
Repl. Group:”New-York:A”
Repl. Group:”New-York:B”
Repl. Group:”New-York:C”
Repl. Group:”New-York:D”
Valid Configuration
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Now provision a VM with two disks, one associated with replication group Anaheim:B, the second
associated with replication group Anaheim:D. This configuration is invalid. Both replication groups
replicate to the New-York fault domain, however, only one replicates to the Boulder fault domain.
Source
Target
Fault Domain: “Anaheim”
Fault Domain: “Boulder”
Repl. Group:”Anaheim:A”
Repl. Group:”Boulder:A”
Repl. Group:”Anaheim:B”
Repl. Group:”Boulder:B”
Repl. Group:”Anaheim:C”
Repl. Group:”Boulder:C”
Repl. Group:”Anaheim:D”
Fault Domain: “New-York”
Repl. Group:”Anaheim:E”
Repl. Group:”New-York:A”
Repl. Group:”New-York:B”
Repl. Group:”New-York:C”
Repl. Group:”New-York:D”
Invalid Configuration
Virtual Volumes Replication Workflow
If information about replication capabilities of the Virtual Volumes storage array shows in vCenter Server,
you can activate replication for your virtual machines.
The workflow to activate replication for your virtual machines includes steps typical for the virtual machine
provisioning on Virtual Volumes storage.
1
Define the VM storage policy compatible with replication storage. The policy must include the
replication component on the Rule Set page. See “Define a VM Storage Policy for Virtual Volumes,” on
page 253.
After you configure the storage policy that includes replication, vCenter Server discovers available
replication groups.
2
Assign the replication policy to your virtual machine. If configured, select a compatible replication
group, or use the automatic assignment. See “Assign the Virtual Volumes Storage Policy to Virtual
Machines,” on page 254.
Replication Guidelines and Considerations
When you use replication with Virtual Volumes, specific considerations apply.
n
VMware, Inc.
You can apply the replication storage policy only to a configuration virtual volume and a data virtual
volume. Other VM objects inherit the replication policy in the following way:
n
The memory virtual volume inherits the policy of the configuration virtual volume.
n
The digest virtual volume inherits the policy of the data virtual volume.
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n
The swap virtual volume, which exists while a virtual machine is powered on, is excluded from
replication.
n
If you do not apply the replication policy to a VM disk, the disk is not replicated.
n
The replication storage policy should not be used as a default storage policy for a datastore. Otherwise,
the policy prevents you from selecting replication groups.
n
Replication preserves snapshot history. If a snapshot was created and replicated, you can recover to the
application consistent snapshot.
n
You can replicate a linked clone. If a linked clone is replicated without its parent, it becomes a full clone.
n
If a descriptor file belongs to a virtual disk of one VM, but resides in the VM home of another VM, both
VMs must be in the same replication group. If the VMs are located in different replication groups, both
of these replication groups must be failed over at the same time. Otherwise, the descriptor might
become unavailable after the failover. As a result, the VM might fail to power on.
n
In your Virtual Volumes with replication environment, you might periodically run a test failover
workflow to ensure that the recovered workloads are functional after a failover.
The resulting test VMs that are created during the test failover are fully functional and suitable for
general administrative operations. However, certain considerations apply:
n
All VMs created during the test failover must be deleted before the test failover stops. The deletion
ensures that any snapshots or snapshot-related virtual volumes that are part of the VM, such as the
snapshot virtual volume, do not interfere with stopping of the test failover.
n
You can create full clones of the test VMs.
n
You can create fast clones only if the policy applied to the new VM contains the same replication
group ID as the VM being cloned. Attempts to place the child VM outside of the replication group
of the parent VM fail.
Best Practices for Working with vSphere Virtual Volumes
Observe the following best practices when you use Virtual Volumes with ESXi and vCenter Server.
n
Guidelines and Limitations in Using vSphere Virtual Volumes on page 260
For the best experience with vSphere Virtual Volumes functionality, you must follow specific
guidelines.
n
Best Practices for Storage Container Provisioning on page 261
Follow these best practices when provisioning storage containers on the vSphere Virtual Volumes
array side.
n
Best Practices for vSphere Virtual Volumes Performance on page 262
To ensure optimal vSphere Virtual Volumes performance results, follow these best practices.
Guidelines and Limitations in Using vSphere Virtual Volumes
For the best experience with vSphere Virtual Volumes functionality, you must follow specific guidelines.
Virtual Volumes supports the following capabilities, features, and VMware products:
n
260
With Virtual Volumes, you can use advanced storage services that include replication, encryption,
deduplication, and compression on individual virtual disks. Check with your storage vendor for
information about services they support with Virtual Volumes.
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n
Virtual Volumes functionality supports backup software that uses vSphere APIs - Data Protection.
Virtual volumes are modeled on virtual disks. Backup products that use vSphere APIs - Data Protection
are as fully supported on virtual volumes as they are on VMDK files on a LUN. Snapshots that are
created by backup software using vSphere APIs - Data Protection look as non-VVols snapshots to
vSphere and the backup software.
Note vSphere Virtual Volumes does not support SAN transport mode. vSphere APIs - Data Protection
automatically selects an alternative data transfer method.
For more information about integration with the vSphere Storage APIs - Data Protection, consult your
backup software vendor.
n
Virtual Volumes supports such vSphere features as vSphere vMotion, Storage vMotion, snapshots,
linked clones, Flash Read Cache, and DRS.
n
You can use clustering products, such as Oracle Real Application Clusters, with Virtual Volumes. To use
these products, you activate the multiwrite setting for a virtual disk stored on the VVol datastore.
For more details, see the knowledge base article at http://kb.vmware.com/kb/2112039. For a complete list of
features and products that Virtual Volumes functionality supports, see VMware Product Interoperability
Matrixes.
vSphere Virtual Volumes Limitations
Improve your experience with vSphere Virtual Volumes by knowing the following limitations:
Because the Virtual Volumes environment requires vCenter Server, you cannot use Virtual Volumes
n
with a standalone host.
n
Virtual Volumes functionality does not support RDMs.
n
A Virtual Volumes storage container cannot span multiple physical arrays. Some vendors present
multiple physical arrays as a single array. In such cases, you still technically use one logical array.
n
Host profiles that contain Virtual Volumes datastores are vCenter Server specific. After you extract this
type of host profile, you can attach it only to hosts and clusters managed by the same vCenter Server as
the reference host.
Best Practices for Storage Container Provisioning
Follow these best practices when provisioning storage containers on the vSphere Virtual Volumes array
side.
Creating Containers Based on Your Limits
Because storage containers apply logical limits when grouping virtual volumes, the container must match
the boundaries that you want to apply.
Examples might include a container created for a tenant in a multitenant deployment, or a container for a
department in an enterprise deployment.
Organizations or departments, for example, Human Resources and Finance
n
n
Groups or projects, for example, Team A and Red Team
n
Customers
Putting All Storage Capabilities in a Single Container
Storage containers are individual datastores. A single storage container can export multiple storage
capability profiles. As a result, virtual machines with diverse needs and different storage policy settings can
be a part of the same storage container.
Changing storage profiles must be an array-side operation, not a storage migration to another container.
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Avoiding Over-Provisioning Your Storage Containers
When you provision a storage container, the space limits that you apply as part of the container
configuration are only logical limits. Do not provision the container larger than necessary for the anticipated
use. If you later increase the size of the container, you do not need to reformat or repartition it.
Using Storage-Specific Management UI to Provision Protocol Endpoints
Every storage container needs protocol endpoints (PEs) that are accessible to ESXi hosts.
When you use block storage, the PE represents a proxy LUN defined by a T10-based LUN WWN. For NFS
storage, the PE is a mount point, such as an IP address or DNS name, and a share name.
Typically, configuration of PEs is array-specific. When you configure PEs, you might need to associate them
with specific storage processors, or with certain hosts. To avoid errors when creating PEs, do not configure
them manually. Instead, when possible, use storage-specific management tools.
No Assignment of IDs Above Disk.MaxLUN to Protocol Endpoint LUNs
By default, an ESXi host can access LUN IDs that are within the range of 0 to 1023. If the ID of the protocol
endpoint LUN that you configure is 1024 or greater, the host might ignore the PE.
If your environment uses LUN IDs that are greater than 1023, change the number of scanned LUNs through
the Disk.MaxLUN parameter. See “Change the Number of Scanned Storage Devices,” on page 122.
Best Practices for vSphere Virtual Volumes Performance
To ensure optimal vSphere Virtual Volumes performance results, follow these best practices.
Using Different VM Storage Policies for Individual Virtual Volumes
By default, all components of a virtual machine in the Virtual Volumes environment get a single VM storage
policy. However, different components might have different performance characteristics, for example, a
database virtual disk and a corresponding log virtual disk. Depending on performance requirements, you
can assign different VM storage policies to individual virtual disks and to the VM home file, or config-VVol.
When you use vSphere Web Client, you cannot change the VM storage policy assignment for swap-VVol,
memory-VVol, or snapshot-VVol.
See “Assign the Virtual Volumes Storage Policy to Virtual Machines,” on page 254.
Getting a Host Profile with Virtual Volumes
The best way to get a host profile with Virtual Volumes is to configure a reference host and extract its profile.
If you manually edit an existing host profile in the vSphere Web Client and attach the edited profile to a new
host, you might trigger compliance errors and other unpredictable problems. For more details, see the
VMware Knowledge Base article 2146394.
Monitoring I/O Load on Individual Protocol Endpoint
262
n
All virtual volume I/O goes through protocol endpoints (PEs). Arrays select protocol endpoints from
several PEs that are accessible to an ESXi host. Arrays can do load balancing and change the binding
path that connects the virtual volume and the PE. See “Binding and Unbinding Virtual Volumes to
Protocol Endpoints,” on page 243.
n
On block storage, ESXi gives a large queue depth to I/Os because of a potentially high number of virtual
volumes. The Scsi.ScsiVVolPESNRO parameter controls the number of I/Os that can be queued for PEs.
You can configure the parameter on the Advanced System Settings page of the vSphere Web Client. See
“Set Advanced Host Attributes,” on page 179.
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Monitoring Array Limitations
A single VM might occupy multiple virtual volumes. See “Virtual Volumes,” on page 240.
Suppose that your VM has two virtual disks, and you take two snapshots with memory. Your VM might
occupy up to 10 VVol objects: a config-VVol, a swap-VVol, 2 data-VVols, 4 snapshot-VVols, and 2 memory
snapshot-VVols.
Ensuring that Storage Provider Is Available
To access vSphere Virtual Volumes storage, your ESXi host requires a storage provider (VASA provider). To
ensure that the storage provider is always available, follow these guidelines:
n
Do not migrate a storage provider VM to Virtual Volumes storage.
n
Back up your storage provider VM.
n
When appropriate, use vSphere HA or Site Recovery Manager to protect the storage provider VM.
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Filtering Virtual Machine I/O
22
I/O filters are software components that can be installed on ESXi hosts and can offer additional data services
to virtual machines. The filters process I/O requests, which move between the guest operating system of a
virtual machine and virtual disks.
The I/O filters can be offered by VMware or created by third parties through vSphere APIs for I/O Filtering
(VAIO).
This chapter includes the following topics:
n
“About I/O Filters,” on page 265
n
“Using Flash Storage Devices with Cache I/O Filters,” on page 268
n
“System Requirements for I/O Filters,” on page 268
n
“Configure I/O Filters in the vSphere Environment,” on page 269
n
“Managing I/O Filters,” on page 274
n
“I/O Filter Guidelines and Best Practices,” on page 275
About I/O Filters
I/O filters can gain direct access to the virtual machine I/O path. You can enable the I/O filter for an
individual virtual disk level. The I/O filters are independent of the storage topology.
VMware offers certain categories of I/O filters. In addition, third-party vendors can create the I/O filters.
Typically, they are distributed as packages that provide an installer to deploy the filter components on
vCenter Server and ESXi host clusters.
When I/O filters are deployed on the cluster, vCenter Server configures and registers an I/O filter storage
provider, also called a VASA provider, for each host in the cluster. The storage providers communicate with
vCenter Server and make data services offered by the I/O filter visible in the VM Storage Policies interface.
You can reference these data services when defining common rules for a VM policy. After you associate
virtual disks with this policy, the I/O filters are enabled on the virtual disks.
Datastore Support
I/O filters can support all datastore types including the following:
n
VMFS
n
NFS 3
n
NFS 4.1
n
Virtual Volumes (VVol)
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Virtual SAN
Types of I/O Filters
VMware provides certain categories of I/O filters that are installed on your ESXi hosts. In addition, VMware
partners can create the I/O filters through the vSphere APIs for I/O Filtering (VAIO) developer program. The
I/O filters can serve multiple purposes.
The supported types of filters include the following:
n
Replication. Replicates all write I/O operations to an external target location, such as another host or
cluster.
n
Encryption. Offered by VMware. Provides encryption mechanisms for virtual machines. For more
information, see the vSphere Security documentation.
n
Caching. Implements a cache for virtual disk data. The filter can use a local flash storage device to cache
the data and increase the IOPS and hardware utilization rates for the virtual disk. If you use the caching
filter, you might need to configure a Virtual Flash Resource.
n
Storage I/O control. Offered by VMware. Throttles the I/O load towards a datastore and controls the
amount of storage I/O that is allocated to virtual machines during periods of I/O congestion. For more
information, see the vSphere Resource Management documentation.
Note You can install several filters from the same category, such as caching, on your ESXi host. However,
you can have only one filter from the same category per virtual disk.
I/O Filtering Components
Several components are involved in the I/O filtering process.
The components of I/O filtering include the following:
VAIO Filter Framework
A combination of user world and VMkernel infrastructure provided by ESXi
that allows to add filter plug-ins to the I/O path to and from virtual disks.
The infrastructure includes an I/O filter storage provider (VASA provider).
The provider integrates with the Storage Policy Based Management (SPBM)
system and exports filter capabilities to vCenter Server.
I/O Filter Plug-In
A software component provided by VMware or developed by VMware
partners that intercepts and filters I/O data in transit between virtual disks
and guest operating systems.
CIM Provider
If VMware partners develop the I/O filters, the partners can provide an
optional component that configures and manages I/O filter plug-ins.
vSphere Web Client
Plug-In
When developing I/O filters, VMware partners can include this optional
plug-in. The plug-in provides vSphere administrators with methods for
communication with an I/O filter CIM provider to receive monitoring
information about the I/O filter status. It can also send configuration
commands to the CIM provider to configure its I/O filters.
I/O Filter Daemon
An optional component that VMware partners can develop. You can use it as
an additional service that interacts with the individual filter instances
running on a host. The service can establish cross-host network
communication channels.
The following figure illustrates the components of I/O filtering and the flow of I/Os between the guest OS
and the virtual disk.
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Virtual Machine
GuestOS
I/O Path
Filter 1
vCenter Server
Filter 2
3rd Party
CIM Provider
3rd Party Web
Client Extension
Plugin
Filter N
VAIO Filter Framework
I/O Path
Virtual Disk
Each Virtual Machine Executable (VMX) component of a virtual machine contains a Filter Framework that
manages the I/O filter plug-ins attached to the virtual disk. The Filter Framework invokes filters when the
I/O requests move between the guest operating system and the virtual disk. Also, the filter intercepts any
I/O access towards the virtual disk that happens outside of a running VM.
The filters execute sequentially in a specific order. For example, a replication filter executes before a cache
filter. More than one filter can filter the virtual disk, but only one for each category.
Once all filters for the particular disk verify the I/O request, the request moves to its destination, either the
VM or the virtual disk.
Because the filters run in user space, any filter failures impact only the VM, but do not affect the ESXi host.
Storage Providers for I/O Filters
When I/O filters are installed on ESXi hosts, the I/O filter framework configures and registers a storage
provider, also called a VASA provider, for each host in the cluster.
Storage providers for I/O filtering are software components that are offered by vSphere. They integrate with
I/O filters and report data service capabilities that I/O filters support to vCenter Server.
The capabilities populate the VM Storage Policies interface and can be referenced in a VM storage policy.
You then apply this policy to virtual disks, so that the I/O filters can process I/O for the disks.
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Using Flash Storage Devices with Cache I/O Filters
A cache I/O filter can use a local flash device to cache virtual machine data.
If your caching I/O filter uses local flash devices, you need to configure a virtual flash resource, also known
as VFFS volume. You configure the resource on your ESXi host before activating the filter. While processing
the virtual machine read I/Os, the filter creates a virtual machine cache and places it on the VFFS volume.
VM
I/O Path
Cache Filter
I/O Path
Virtual
Machine
Cache
Virtual Flash Resource (VFFS)
SSD
SSD
SSD
SSD
SSD
SSD
Flash
Storage
Devices
Flash
Storage
Devices
ESXi
To set up a virtual flash resource, you use flash devices that are connected to your host. To increase the
capacity of your virtual flash resource, you can add more flash drives. An individual flash drive must be
exclusively allocated to a virtual flash resource and cannot be shared with any other vSphere service, such
as Virtual SAN or VMFS.
Flash Read Cache and caching I/O filters are mutually exclusive because both functionalities use the virtual
flash resource on the host. You cannot enable Flash Read Cache on a virtual disk with the cache I/O filters.
Similarly, if a virtual machine has Flash Read Cache configured, it cannot use the cache I/O filters.
System Requirements for I/O Filters
To be able to use I/O filters in your environment, you must follow specific requirements.
The following requirements apply.
n
268
Use the latest version of ESXi and vCenter Server compatible with I/O filters. Older versions might not
support I/O filters, or provide only partial support.
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n
Check for any additional requirements that individual partner solutions might have. In specific cases,
your environment might need flash devices, extra physical memory, or network connectivity and
bandwidth. For information, contact your vendor or your VMware representative.
n
Web server to host partner packages for filter installation. The server must remain available after initial
installation. When a new host joins the cluster, the server pushes appropriate I/O filter components to
the host.
Configure I/O Filters in the vSphere Environment
To enable data services that the I/O filters provide for your virtual machines, follow several steps.
Prerequisites
n
Create a cluster that includes at least one ESXi host.
n
In addition to the I/O filters offered by VMware, you can use the filters that VMware partners create
through the vSphere APIs for I/O Filtering (VAIO) developer program. Typically, the filter packages are
distributed as vSphere Installation Bundles (VIBs) and can include I/O filter daemons, CIM providers,
and other associated components. For information, contact your vendor or your VMware
representative.
Procedure
1
Install I/O Filters in a Cluster on page 269
If you use I/O filters provided by third parties, install the I/O filters in an ESXi host cluster.
2
View I/O Filters and Storage Providers on page 270
You can review I/O filters available in your environment and verify that the I/O filter providers appear
as expected and are active.
3
Configure Virtual Flash Resource for Caching I/O Filters on page 270
If your caching I/O filter uses local flash devices, configure a virtual flash resource, also known as
VFFS volume. You configure the resource on your ESXi host before activating the filter.
4
Enable I/O Filter Data Services on Virtual Disks on page 271
Enabling data services that I/O filters provide is a two-step process. You create a virtual machine
policy based on data service capabilities that the I/O filters provide, and then attach this policy to a
virtual machine.
What to do next
For information about troubleshooting I/O filters, see the vSphere Troubleshooting documentation.
Install I/O Filters in a Cluster
If you use I/O filters provided by third parties, install the I/O filters in an ESXi host cluster.
VMware partners create I/O filters through the vSphere APIs for I/O Filtering (VAIO) developer program.
The filter packages are typically distributed as vSphere Installation Bundles (VIBs). The VIB package can
include I/O filter daemons, CIM providers, and other associated components.
Typically, to deploy the filters, you run installers provided by vendors. Installation is performed at an ESXi
cluster lever. You cannot install the filters on selected hosts.
Prerequisites
n
Required privileges: Host.Config.Patch.
n
Verify that the I/O filter solution integrates with vSphere ESX Agent Manager and is certified by
VMware.
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Procedure
u
Run the installer that the vendor provided.
The installer deploys the appropriate I/O filter extension on vCenter Server and the filter components
on all hosts within a cluster.
A storage provider, also called a VASA provider, is automatically registered for every ESXi host in the
cluster. Successful auto-registration of the I/O filter storage providers triggers an event at the host level.
If the storage providers fail to auto-register, the system raises alarms on the hosts.
View I/O Filters and Storage Providers
You can review I/O filters available in your environment and verify that the I/O filter providers appear as
expected and are active.
When you install a third-party I/O filter, a storage provider, also called VASA provider, is automatically
registered for every ESXi host in the cluster. Successful auto-registration of the I/O filter storage providers
triggers an event at the host level. If the storage providers fail to auto-register, the system raises alarms on
the hosts.
Procedure
1
Verify that the I/O filter storage providers appear as expected and are active.
a
Browse to vCenter Server in the vSphere Web Client navigator.
b
Click the Configure tab, and click Storage Providers.
c
Review the storage providers for I/O filters.
When the I/O filter providers are properly registered, capabilities and data services that the filters offer
populate the VM Storage Policies interface.
2
Verify that the I/O filter components are listed on your cluster and ESXi hosts.
Option
Actions
View I/O filters on a cluster
a
b
c
Navigate to the cluster.
Click the Configure tab.
Under Configuarion, click I/O Filters to review the filters installed in
the cluster.
View I/O filters on a host
a
b
c
Navigate to the host.
Click the Configure tab.
Under Storage, click I/O Filters to review the filters installed on the
host.
Configure Virtual Flash Resource for Caching I/O Filters
If your caching I/O filter uses local flash devices, configure a virtual flash resource, also known as VFFS
volume. You configure the resource on your ESXi host before activating the filter.
Prerequisites
To determine whether the virtual flash resource must be enabled, check with your I/O filter vendor.
Procedure
270
1
In the vSphere Web Client, navigate to the host.
2
Click the Configure tab.
3
Under Virtual Flash, select Virtual Flash Resource Management and click Add Capacity.
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4
From the list of available flash drives, select one or more drives to use for the virtual flash resource and
click OK.
The virtual flash resource is created. The Device Backing area lists all the drives that you use for the virtual
flash resource.
Enable I/O Filter Data Services on Virtual Disks
Enabling data services that I/O filters provide is a two-step process. You create a virtual machine policy
based on data service capabilities that the I/O filters provide, and then attach this policy to a virtual
machine.
Prerequisites
For the caching I/O filters, configure the virtual flash resource on your ESXi host.
Procedure
1
Define a VM Policy Based on I/O Filter Capabilities on page 271
To enable I/O filters for virtual machines, you must first create a virtual machine policy that lists data
service capabilities provided by the I/O filters.
2
Assign the I/O Filter Policy to Virtual Machines on page 273
To activate data services that I/O filters provide, associate the I/O filter policy with virtual disks. You
can assign the policy when you create or edit a virtual machine.
What to do next
If you later want to disable the I/O filter for a virtual machine, you can remove the filter rules from the VM
storage policy and re-apply the policy. See “Edit or Clone a VM Storage Policy,” on page 227. Or you can edit
the settings of the virtual machine and select a different storage policy that does not include the filter.
Define a VM Policy Based on I/O Filter Capabilities
To enable I/O filters for virtual machines, you must first create a virtual machine policy that lists data service
capabilities provided by the I/O filters.
The I/O filter capabilities are displayed on the Common rules page of the VM Storage Policies wizard. The
policy that enables I/O filters must include common rules. However, adding placement rules is optional.
Depending on the I/O filters installed in your environment, the data services can belong to various
categories, including caching, replication, and so on. By referencing the specific category in the storage
policy, you request the service for your virtual machine.
If your I/O filters and storage offer the same service category, for example, encryption, your policy can
request this service from both providers. As a result, the virtual machine data is encrypted twice, by the I/O
filter and your storage. However, replication provided by Virtual Volumes and replication provided by the
I/O filter cannot coexist in the same storage policy.
Prerequisites
n
Verify that the I/O filter storage provider is available and active. See “View I/O Filters and Storage
Providers,” on page 270.
n
Define appropriate storage policy components. See “Create Storage Policy Components,” on page 221.
n
Required privileges: VM storage policies.Update and VM storage policies.View.
Procedure
1
From the vSphere Web Client Home, click Policies and Profiles > VM Storage Policies.
2
Click the VM Storage Policies tab.
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3
Click the Create a New VM Storage Policy icon.
4
Select the vCenter Server instance.
5
Type a name, for example I/O Filters, and a description for the policy and click Next.
6
On the Common Rules page, define the I/O filters.
a
Select Use common rules in the storage policy.
b
Click the Add component (
for example, Replication.
c
Define rules for the data service category by specifying an appropriate provider and values for the
rules. Or select the data service from the list of predefined components.
Option
Component Name
) icon and select a data service category from the drop-down menu,
Description
This option is available if you have predefined storage policy
components in your database. If you know which component to use,
select it from the list to add to the VM storage policy.
See all
Review all component available for the category. To include a specific
component, select it from the list and click OK.
Custom
Define custom rules for the data service category by specifying an
appropriate provider and values for the rules.
Note If you use encryption with other I/O filters, set the Allow I/O filters before encryption
parameter to True, so that other filters, such as replication, can analyze clear text data before it is
encrypted.
d
Add more components to request other data services.
You can use only one component from the same category, for example caching, per a set of common
or regular rules.
e
7
Click Next.
If your policy includes placement rules, on the Rule Set page, specify storage placement requirements
and click Next.
Note If you plan to migrate the virtual machine with the I/O filters across different types of datastores,
make sure that the policy includes placement rules for every target datastore. For example, if you
migrate your virtual machine between the VMFS and Virtual Volumes datastores, create a mixed VM
storage policy. The policy must include tag-based rule for the VMFS datastore and rules for the Virtual
Volumes datastore.
8
On the Storage Compatibility page, review the list of available datastores and click Next.
To be compatible with the I/O filter policy, datastores must be connected to host with I/O filters and
satisfy storage requirements of the policy.
9
Complete the creation of the storage policy and click Finish.
The new policy is added to the list.
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Assign the I/O Filter Policy to Virtual Machines
To activate data services that I/O filters provide, associate the I/O filter policy with virtual disks. You can
assign the policy when you create or edit a virtual machine.
You can assign the I/O filter policy during an initial deployment of a virtual machine. This topic describes
how to assign the policy when you create a new virtual machine. For information about other deployment
methods, see the vSphere Virtual Machine Administration documentation.
Note You cannot change or assign the I/O filter policy when migrating or cloning a virtual machine.
Prerequisites
Verify that the I/O filter is installed on the ESXi host where the virtual machine runs.
Procedure
1
In the vSphere Web Client, start the virtual machine provisioning process and follow the appropriate
steps.
2
Assign the same storage policy to all virtual machine files and disks.
a
On the Select storage page, select a storage policy from the VM Storage Policy drop-down menu.
b
Select the datastore from the list of compatible datastores and click Next.
The datastore becomes the destination storage resource for the virtual machine configuration file
and all virtual disks. The policy also activates I/O filter services for the virtual disks.
3
Change the VM storage policy for the virtual disk.
Use this option to enable I/O filters just for your virtual disks.
a
On the Customize hardware page, expand the New hard disk pane.
b
From the VM storage policy drop-down menu, select the storage policy to assign to the virtual
disk.
c
(Optional) Change the storage location of the virtual disk.
Use this option to store the virtual disk on a datastore other than the datastore where the VM
configuration file resides.
4
Complete the virtual machine provisioning process.
After you create the virtual machine, the Summary tab displays the assigned storage policies and their
compliance status.
What to do next
You can later change the virtual policy assignment. See “Change Storage Policy Assignment for Virtual
Machine Files and Disks,” on page 228.
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Managing I/O Filters
You can run the installer provided by your vendor to install, uninstall, or upgrade I/O filters.
When you work with I/O filters, the following considerations apply:
n
vCenter Server uses ESX Agent Manager (EAM) to install and uninstall I/O filters. As an administrator,
never invoke EAM APIs directly for EAM agencies that are created or used by vCenter Server. All
operations related to I/O filters must go through VIM APIs. If you accidentally modify an EAM agency
that was created by vCenter Server, you must revert the changes. If you accidentally destroy an EAM
agency that is used by I/O filters, you must call Vim.IoFilterManager#uninstallIoFilter to uninstall
the affected I/O filters. After uninstalling, perform a fresh reinstall.
n
When a new host joins the cluster that has I/O filters, the filters installed on the cluster are deployed on
the host. vCenter Server registers the I/O filter storage provider for the host. Any cluster changes
become visible in the VM Storage Policies interface of the vSphere Web Client.
n
When you move a host out of a cluster or remove it from vCenter Server, the I/O filters are uninstalled
from the host. vCenter Server unregisters the I/O filter storage provider.
n
If you use a stateless ESXi host, it might lose its I/O filter VIBs during a reboot. vCenter Server checks
the bundles installed on the host after it reboots, and pushes the I/O filter VIBs to the host if necessary.
Uninstall I/O Filters from a Cluster
You can uninstall I/O filters deployed in an ESXi host cluster.
Prerequisites
n
Required privileges: Host.Config.Patch.
Procedure
1
Uninstall the I/O filter by running the installer that your vendor provides.
During uninstallation, vSphere ESX Agent Manager automatically places the hosts into maintenance
mode.
If the uninstallation is successful, the filter and any related components are removed from the hosts.
2
Verify that the I/O filter components are properly uninstalled from your ESXi hosts:
esxcli --server=server_name software vib list
The uninstalled filter no longer appears on the list.
Upgrade I/O Filters in a Cluster
Use installers provided by I/O filter vendors to upgrade I/O filters deployed in an ESXi host cluster.
An upgrade consists of uninstalling the old filter components and replacing them with the new filter
components. To determine whether an installation is an upgrade, vCenter Server checks the names and
versions of existing filters. If the existing filter names match the names of the new filters but have different
versions, the installation is considered an upgrade.
Prerequisites
n
274
Required privileges:Host.Config.Patch.
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Procedure
1
To upgrade the filter, run the vendor-provided installer.
During the upgrade, vSphere ESX Agent Manager automatically places the hosts into maintenance
mode.
The installer identifies any existing filter components and removes them before installing the new filter
components.
2
Verify that the I/O filter components are properly uninstalled from your ESXi hosts:
esxcli --server=server_name software vib list
After the upgrade, vSphere ESX Agent Manager places the hosts back into operational mode.
I/O Filter Guidelines and Best Practices
When you use I/O filters in your environment, follow specific guidelines and best practices.
n
Because I/O filters are datastore-agnostic, all types of datastores, including VMFS, NFS, Virtual
Volumes, and Virtual SAN, are compatible with I/O filters.
n
I/O filters support RDMs in virtual compatibility mode. No support is provided to RDMs in physical
compatibility mode.
n
Flash Read Cache and caching I/O filters are mutually exclusive because both functionalities use the
virtual flash resource on the host. You cannot enable Flash Read Cache on a virtual disk with the cache
I/O filters. Similarly, if a virtual machine has Flash Read Cache configured, it cannot use the cache I/O
filters.
n
You cannot change or assign the I/O filter policy while migrating or cloning a virtual machine. You can
change the policy after you complete the migration or cloning.
n
When you clone or migrate a virtual machine with I/O filter policy from one host to another, make sure
that the destination host has a compatible filter installed. This requirement applies to migrations
initiated by an administrator or by such functionalities as HA or DRS.
n
When you convert a template to a virtual machine, and the template is configured with I/O filter policy,
the destination host must have the compatible I/O filter installed.
n
If you use vCenter Site Recovery Manager to replicate virtual disks, the resulting disks on the recovery
site do not have the I/O filter policies. You must create the I/O filter policies in the recovery site and
reattach them to the replicated disks.
n
You can attach an encryption I/O filter to a new virtual disk when you create a virtual machine. You
cannot attach the encryption filter to an existing virtual disk.
n
If your virtual machine has a snapshot tree associated with it, you cannot add, change, or remove the
I/O filter policy for the virtual machine.
For information about troubleshooting I/O filters, see the vSphere Troubleshooting documentation.
Migrating Virtual Machines with I/O Filters
When you migrate a virtual machine with I/O filters, specific considerations apply.
If you use Storage vMotion to migrate a virtual machine with I/O filters, a destination datastore must be
connected to hosts with compatible I/O filters installed.
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You might need to migrate a virtual machine with I/O filters across different types of datastores, for example
between VMFS and Virtual Volumes. If you do so, make sure that the VM storage policy includes rule sets
for every type of datastore you are planning to use. For example, if you migrate your virtual machine
between the VMFS and Virtual Volumes datastores, create a mixed VM storage policy that includes the
following rules:
n
Common Rules for the I/O filters
n
Rule Set 1 for the VMFS datastore. Because Storage Policy Based Management does not offer an explicit
VMFS policy, the rule set must include tag-based rules for the VMFS datastore.
n
Rule Set 2 for the Virtual Volumes datastore
When Storage vMotion migrates the virtual machine, the correct rule set that corresponds to the target
datastore is selected. The I/O filter rules remain unchanged.
If you do not specify rules for datastores and define only Common Rules for the I/O filters, the system
applies default storage policies for the datastores.
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Storage Hardware Acceleration
23
The hardware acceleration functionality enables the ESXi host to integrate with compliant storage arrays
and offload specific virtual machine and storage management operations to storage hardware. With the
storage hardware assistance, your host performs these operations faster and consumes less CPU, memory,
and storage fabric bandwidth.
The hardware acceleration is supported by block storage devices, Fibre Channel and iSCSI, and NAS
devices.
For additional details, see the VMware knowledge base article at http://kb.vmware.com/kb/1021976.
This chapter includes the following topics:
n
“Hardware Acceleration Benefits,” on page 277
n
“Hardware Acceleration Requirements,” on page 278
n
“Hardware Acceleration Support Status,” on page 278
n
“Hardware Acceleration for Block Storage Devices,” on page 278
n
“Hardware Acceleration on NAS Devices,” on page 283
n
“Hardware Acceleration Considerations,” on page 286
Hardware Acceleration Benefits
When the hardware acceleration functionality is supported, the host can get hardware assistance and
perform several tasks faster and more efficiently.
The host can get assistance with the following activities:
n
Migrating virtual machines with Storage vMotion
n
Deploying virtual machines from templates
n
Cloning virtual machines or templates
n
VMFS clustered locking and metadata operations for virtual machine files
n
Provisioning thick virtual disks
n
Creating fault-tolerant virtual machines
n
Creating and cloning thick disks on NFS datastores
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Hardware Acceleration Requirements
The hardware acceleration functionality works only if you use an appropriate host and storage array
combination.
Table 23‑1. Hardware Acceleration Storage Requirements
ESXi
Block Storage Devices
NAS Devices
ESXi
Support T10 SCSI standard, or block
storage plug-ins for array integration
(VAAI)
Support NAS plug-ins for array
integration
Note If your SAN or NAS storage fabric uses an intermediate appliance in front of a storage system that
supports hardware acceleration, the intermediate appliance must also support hardware acceleration and be
properly certified. The intermediate appliance might be a storage virtualization appliance, I/O acceleration
appliance, encryption appliance, and so on.
Hardware Acceleration Support Status
For each storage device and datastore, the vSphere Web Client display the hardware acceleration support
status.
The status values are Unknown, Supported, and Not Supported. The initial value is Unknown.
For block devices, the status changes to Supported after the host successfully performs the offload operation.
If the offload operation fails, the status changes to Not Supported. The status remains Unknown if the
device provides partial hardware acceleration support.
With NAS, the status becomes Supported when the storage can perform at least one hardware offload
operation.
When storage devices do not support or provide partial support for the host operations, your host reverts to
its native methods to perform unsupported operations.
Hardware Acceleration for Block Storage Devices
With hardware acceleration, your host can integrate with block storage devices, Fibre Channel or iSCSI, and
use certain storage array operations.
ESXi hardware acceleration supports the following array operations:
n
Full copy, also called clone blocks or copy offload. Enables the storage arrays to make full copies of data
within the array without having the host read and write the data. This operation reduces the time and
network load when cloning virtual machines, provisioning from a template, or migrating with vMotion.
n
Block zeroing, also called write same. Enables storage arrays to zero out a large number of blocks to
provide newly allocated storage, free of previously written data. This operation reduces the time and
network load when creating virtual machines and formatting virtual disks.
n
Hardware assisted locking, also called atomic test and set (ATS). Supports discrete virtual machine
locking without use of SCSI reservations. This operation allows disk locking per sector, instead of the
entire LUN as with SCSI reservations.
Check with your vendor for the hardware acceleration support. Certain storage arrays require that you
activate the support on the storage side.
On your host, the hardware acceleration is enabled by default. If your storage does not support the
hardware acceleration, you can disable it.
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In addition to hardware acceleration support, ESXi includes support for array thin provisioning. For
information, see “ESXi and Array Thin Provisioning,” on page 291.
Disable Hardware Acceleration for Block Storage Devices
On your host, the hardware acceleration for block storage devices is enabled by default. You can use the
vSphere Web Client advanced settings to disable the hardware acceleration operations.
As with any advanced settings, before you disable the hardware acceleration, consult with the VMware
support team.
Procedure
1
Browse to the host in the vSphere Web Client navigator.
2
Click the Configure tab.
3
Under System, click Advanced System Settings.
4
Change the value for any of the options to 0 (disabled):
n
VMFS3.HardwareAcceleratedLocking
n
DataMover.HardwareAcceleratedMove
n
DataMover.HardwareAcceleratedInit
Managing Hardware Acceleration on Block Storage Devices
To integrate with the block storage arrays and to benefit from the array hardware operations, vSphere uses
the ESXi extensions referred to as Storage APIs - Array Integration, formerly called VAAI.
In the vSphere 5.x and later releases, these extensions are implemented as the T10 SCSI based commands. As
a result, with the devices that support the T10 SCSI standard, your ESXi host can communicate directly and
does not require the VAAI plug-ins.
If the device does not support T10 SCSI or provides partial support, ESXi reverts to using the VAAI plug-ins,
installed on your host, or uses a combination of the T10 SCSI commands and plug-ins. The VAAI plug-ins
are vendor-specific and can be either VMware or partner developed. To manage the VAAI capable device,
your host attaches the VAAI filter and vendor-specific VAAI plug-in to the device.
For information about whether your storage requires VAAI plug-ins or supports hardware acceleration
through T10 SCSI commands, see the VMware Compatibility Guide or check with your storage vendor.
You can use several esxcli commands to query storage devices for the hardware acceleration support
information. For the devices that require the VAAI plug-ins, the claim rule commands are also available. For
information about esxcli commands, see Getting Started with vSphere Command-Line Interfaces.
Display Hardware Acceleration Plug-Ins and Filter
To communicate with the devices that do not support the T10 SCSI standard, your host uses a combination
of a single VAAI filter and a vendor-specific VAAI plug-in. Use the esxcli command to view the hardware
acceleration filter and plug-ins currently loaded into your system.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
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Procedure
u
Run the esxcli --server=server_name storage core plugin list --plugin-class=value command.
For value, enter one of the following options:
n
Type VAAI to display plug-ins.
The output of this command is similar to the following example:
#esxcli --server=server_name storage core plugin list --plugin-class=VAAI
Plugin name
Plugin class
VMW_VAAIP_EQL
VAAI
VMW_VAAIP_NETAPP
VAAI
VMW_VAAIP_CX
VAAI
n
Type Filter to display the Filter.
The output of this command is similar to the following example:
esxcli --server=server_name storage core plugin list --plugin-class=Filter
Plugin name Plugin class
VAAI_FILTER Filter
Verify Hardware Acceleration Support Status
Use the esxcli command to verify the hardware acceleration support status of a particular storage device.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
Run the esxcli --server=server_name storage core device list -d=device_ID command.
The output shows the hardware acceleration, or VAAI, status that can be unknown, supported, or
unsupported.
# esxcli --server=server_name storage core device list -d naa.XXXXXXXXXXXX4c
naa.XXXXXXXXXXXX4c
Display Name: XXXX Fibre Channel Disk(naa.XXXXXXXXXXXX4c)
Size: 20480
Device Type: Direct-Access
Multipath Plugin: NMP
XXXXXXXXXXXXXXXX
Attached Filters: VAAI_FILTER
VAAI Status: supported
XXXXXXXXXXXXXXXX
Verify Hardware Acceleration Support Details
Use the esxcli command to query the block storage device about the hardware acceleration support the
device provides.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
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Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
Run the esxcli --server=server_name storage core device vaai status get -d=device_ID
command.
If the device is managed by a VAAI plug-in, the output shows the name of the plug-in attached to the
device. The output also shows the support status for each T10 SCSI based primitive, if available. Output
appears in the following example:
# esxcli --server=server_name storage core device vaai status get -d naa.XXXXXXXXXXXX4c
naa.XXXXXXXXXXXX4c
VAAI Plugin Name: VMW_VAAIP_SYMM
ATS Status: supported
Clone Status: supported
Zero Status: supported
Delete Status: unsupported
List Hardware Acceleration Claim Rules
Each block storage device managed by a VAAI plug-in needs two claim rules, one that specifies the
hardware acceleration filter and another that specifies the hardware acceleration plug-in for the device. You
can use the esxcli commands to list the hardware acceleration filter and plug-in claim rules.
Procedure
1
To list the filter claim rules, run the
esxcli --server=server_name storage core claimrule list --claimrule-class=Filter command.
In this example, the filter claim rules specify devices that should be claimed by the VAAI_FILTER filter.
# esxcli --server=server_name storage core claimrule list
Rule Class
Rule
Class
Type
Plugin
Matches
Filter
65430 runtime vendor VAAI_FILTER vendor=EMC
Filter
65430 file
vendor VAAI_FILTER vendor=EMC
Filter
65431 runtime vendor VAAI_FILTER vendor=DGC
Filter
65431 file
vendor VAAI_FILTER vendor=DGC
2
--claimrule-class=Filter
model=SYMMETRIX
model=SYMMETRIX
model=*
model=*
To list the VAAI plug-in claim rules, run the
esxcli --server=server_name storage core claimrule list --claimrule-class=VAAI command.
In this example, the VAAI claim rules specify devices that should be claimed by a particular VAAI plugin.
esxcli --server=server_name
Rule Class
Rule
Class
VAAI
65430 runtime
VAAI
65430 file
VAAI
65431 runtime
VAAI
65431 file
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storage
Type
vendor
vendor
vendor
vendor
core claimrule
Plugin
VMW_VAAIP_SYMM
VMW_VAAIP_SYMM
VMW_VAAIP_CX
VMW_VAAIP_CX
list --claimrule-class=VAAI
Matches
vendor=EMC model=SYMMETRIX
vendor=EMC model=SYMMETRIX
vendor=DGC model=*
vendor=DGC model=*
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Add Hardware Acceleration Claim Rules
To configure hardware acceleration for a new array, you need to add two claim rules, one for the VAAI filter
and another for the VAAI plug-in. For the new claim rules to be active, you first define the rules and then
load them into your system.
This procedure is for those block storage devices that do not support T10 SCSI commands and instead use
the VAAI plug-ins.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Define a new claim rule for the VAAI filter by running the
esxcli --server=server_name storage core claimrule add --claimrule-class=Filter -plugin=VAAI_FILTER command.
2
3
Define a new claim rule for the VAAI plug-in by running the
esxcli --server=server_name storage core claimrule add --claimrule-class=VAAI command.
Load both claim rules by running the following commands:
esxcli --server=server_name storage core claimrule load --claimrule-class=Filter
esxcli --server=server_name storage core claimrule load --claimrule-class=VAAI
4
Run the VAAI filter claim rule by running the
esxcli --server=server_name storage core claimrule run --claimrule-class=Filter command.
Note Only the Filter-class rules need to be run. When the VAAI filter claims a device, it automatically
finds the proper VAAI plug-in to attach.
Example: Defining Hardware Acceleration Claim Rules
This example shows how to configure hardware acceleration for IBM arrays using the VMW_VAAIP_T10
plug-in. Use the following sequence of commands. For information about the options that the command
takes, see “Add Multipathing Claim Rules,” on page 195.
# esxcli --server=server_name storage core claimrule add --claimrule-class=Filter -plugin=VAAI_FILTER --type=vendor --vendor=IBM --autoassign
# esxcli --server=server_name storage core claimrule add --claimrule-class=VAAI -plugin=VMW_VAAIP_T10 --type=vendor --vendor=IBM --autoassign
# esxcli --server=server_name storage core claimrule load --claimrule-class=Filter
# esxcli --server=server_name storage core claimrule load --claimrule-class=VAAI
# esxcli --server=server_name storage core claimrule run --claimrule-class=Filter
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Delete Hardware Acceleration Claim Rules
Use the esxcli command to delete existing hardware acceleration claim rules.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
Run the following commands:
esxcli --server=server_name storage core claimrule remove -r claimrule_ID --claimruleclass=Filter
esxcli --server=server_name storage core claimrule remove -r claimrule_ID --claimruleclass=VAAI
Hardware Acceleration on NAS Devices
Hardware acceleration allows ESXi hosts to integrate with NAS devices and use several hardware
operations that NAS storage provides. Hardware acceleration uses vSphere APIs for Array Integration
(VAAI) to enable communication between the hosts and storage devices.
The VAAI NAS framework supports both versions of NFS storage, NFS 3 and NFS 4.1.
The VAAI NAS define a set of storage primitives that enable the host to offload certain storage operations to
the array. The following list shows the supported NAS operations:
n
Full File Clone. Enables NAS device to clone virtual disk files. This operation is similar to the VMFS
block cloning, except that NAS devices clone entire files instead of file segments.
n
Reserve Space. Enables storage arrays to allocate space for a virtual disk file in thick format.
Typically, when you create a virtual disk on an NFS datastore, the NAS server determines the allocation
policy. The default allocation policy on most NAS servers is thin and does not guarantee backing
storage to the file. However, the reserve space operation can instruct the NAS device to use vendorspecific mechanisms to reserve space for a virtual disk. As a result, you can create thick virtual disks on
the NFS datastore.
n
Native Snapshot Support. Allows creation of virtual machine snapshots to be offloaded to the array.
n
Extended Statistics. Enables visibility to space usage on NAS devices and is useful for Thin
Provisioning.
With NAS storage devices, the hardware acceleration integration is implemented through vendor-specific
NAS plug-ins. These plug-ins are typically created by vendors and are distributed as VIB packages through
a web page. No claim rules are required for the NAS plug-ins to function.
There are several tools available for installing and upgrading VIB packages. They include the esxcli
commands and vSphere Update Manager. For more information, see the vSphere Upgrade and Installing and
Administering VMware vSphere Update Manager documentation.
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Install NAS Plug-In
Install vendor-distributed hardware acceleration NAS plug-ins on your host.
This topic provides an example for a VIB package installation using the esxcli command. For more details,
see the vSphere Upgrade documentation.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Place your host into the maintenance mode.
2
Set the host acceptance level:
esxcli --server=server_name software acceptance set --level=value
The command controls which VIB package is allowed on the host. The value can be one of the following:
3
n
VMwareCertified
n
VMwareAccepted
n
PartnerSupported
n
CommunitySupported
Install the VIB package:
esxcli --server=server_name software vib install -v|--viburl=URL
The URL specifies the URL to the VIB package to install. http:, https:, ftp:, and file: are supported.
4
Verify that the plug-in is installed:
esxcli --server=server_name software vib list
5
Reboot your host for the installation to take effect.
Uninstall NAS Plug-Ins
To uninstall a NAS plug-in, remove the VIB package from your host.
This topic discusses how to uninstall a VIB package using the esxcli command. For more details, see the
vSphere Upgrade documentation.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
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Procedure
1
Uninstall the plug-in:
esxcli --server=server_name software vib remove -n|--vibname=name
The name is the name of the VIB package to remove.
2
Verify that the plug-in is removed:
esxcli --server=server_name software vib list
3
Reboot your host for the change to take effect.
Update NAS Plug-Ins
Upgrade hardware acceleration NAS plug-ins on your host when a storage vendor releases a new plug-in
version.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
This topic discusses how to update a VIB package using the esxcli command. For more details, see the
vSphere Upgrade documentation.
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
1
Upgrade to a new plug-in version:
esxcli --server=server_name software vib update -v|--viburl=URL
The URL specifies the URL to the VIB package to update. http:, https:, ftp:, and file: are supported.
2
Verify that the correct version is installed:
esxcli --server=server_name software vib list
3
Reboot the host.
Verify Hardware Acceleration Status for NAS
In addition to the client, you can use the esxcli command to verify the hardware acceleration status of the
NAS device.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
Run the esxcli --server=server_name storage nfs list command.
The Hardware Acceleration column in the output shows the status.
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Hardware Acceleration Considerations
When you use the hardware acceleration functionality, certain considerations apply.
Several reasons might cause a hardware-accelerated operation to fail.
For any primitive that the array does not implement, the array returns an error. The error triggers the ESXi
host to attempt the operation using its native methods.
The VMFS data mover does not leverage hardware offloads and instead uses software data movement when
one of the following occurs:
n
The source and destination VMFS datastores have different block sizes.
n
The source file type is RDM and the destination file type is non-RDM (regular file).
n
The source VMDK type is eagerzeroedthick and the destination VMDK type is thin.
n
The source or destination VMDK is in sparse or hosted format.
n
The source virtual machine has a snapshot.
n
The logical address and transfer length in the requested operation are not aligned to the minimum
alignment required by the storage device. All datastores created with the vSphere Web Client are
aligned automatically.
n
The VMFS has multiple LUNs or extents, and they are on different arrays.
Hardware cloning between arrays, even within the same VMFS datastore, does not work.
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Storage Thick and Thin Provisioning
24
vSphere supports two models of storage provisioning, thick provisioning and thin provisioning.
Thick provisioning
It is a traditional model of the storage provisioning. With the thick
provisioning, large amount of storage space is provided in advance in
anticipation of future storage needs. However, the space might remain
unused causing underutilization of storage capacity.
Thin provisioning
This method contrast with thick provisioning and helps you eliminate
storage underutilization problems by allocating storage space in a flexible
on-demand manner. With ESXi, you can use two models of thin
provisioning, array-level and virtual disk-level.
Thin provisioning allows you to report more virtual storage space than there
is real physical capacity. This discrepancy can lead to storage oversubscription, also called over-provisioning. When you use thin provisioning,
monitor actual storage usage to avoid conditions when you run out of
physical storage space.
This chapter includes the following topics:
n
“Virtual Disk Thin Provisioning,” on page 287
n
“ESXi and Array Thin Provisioning,” on page 291
n
“Storage Space Reclamation,” on page 293
Virtual Disk Thin Provisioning
When you create a virtual machine, a certain amount of storage space on a datastore is provisioned to
virtual disk files.
By default, ESXi offers a traditional storage provisioning method for virtual machines. With this method,
you first estimate how much storage the virtual machine will need for its entire life cycle. You then provision
a fixed amount of storage space to its virtual disk in advance, for example, 40GB, and have the entire
provisioned space committed to the virtual disk. A virtual disk that immediately occupies the entire
provisioned space is a thick disk.
ESXi supports thin provisioning for virtual disks. With the disk-level thin provisioning feature, you can
create virtual disks in a thin format. For a thin virtual disk, ESXi provisions the entire space required for the
disk’s current and future activities, for example 40GB. However, the thin disk uses only as much storage
space as the disk needs for its initial operations. In this example, the thin-provisioned disk occupies only
20GB of storage. As the disk requires more space, it can grow into its entire 40GB provisioned space.
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Figure 24‑1. Thick and thin virtual disks
VM 1
VM 2
THICK
THIN
80GB
40GB
40GB
40GB
20GB
provisioned
capacity
used
capacity
virtual disks
datastore
20GB
40GB
About Virtual Disk Provisioning Policies
When you perform certain virtual machine management operations, you can specify a provisioning policy
for the virtual disk file. The operations include creating a virtual disk, cloning a virtual machine to a
template, or migrating a virtual machine.
NFS datastores with Hardware Acceleration and VMFS datastores support the following disk provisioning
policies. On NFS datastores that do not support Hardware Acceleration, only thin format is available.
You can use Storage vMotion or cross-host Storage vMotion to transform virtual disks from one format to
another.
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Thick Provision Lazy
Zeroed
Creates a virtual disk in a default thick format. Space required for the virtual
disk is allocated when the disk is created. Data remaining on the physical
device is not erased during creation, but is zeroed out on demand later on
first write from the virtual machine. Virtual machines do not read stale data
from the physical device.
Thick Provision Eager
Zeroed
A type of thick virtual disk that supports clustering features such as Fault
Tolerance. Space required for the virtual disk is allocated at creation time. In
contrast to the thick provision lazy zeroed format, the data remaining on the
physical device is zeroed out when the virtual disk is created. It might take
longer to create virtual disks in this format than to create other types of
disks.
Thin Provision
Use this format to save storage space. For the thin disk, you provision as
much datastore space as the disk would require based on the value that you
enter for the virtual disk size. However, the thin disk starts small and at first,
uses only as much datastore space as the disk needs for its initial operations.
If the thin disk needs more space later, it can grow to its maximum capacity
and occupy the entire datastore space provisioned to it.
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Thin provisioning is the fastest method to create a virtual disk because it
creates a disk with just the header information. It does not allocate or zero
out storage blocks. Storage blocks are allocated and zeroed out when they
are first accessed.
Note If a virtual disk supports clustering solutions such as Fault Tolerance,
do not make the disk thin.
Create Thin Provisioned Virtual Disks
To save storage space, you can create a virtual disk in thin provisioned format. The thin provisioned virtual
disk starts small and grows as more disk space is required. You can create thin disks only on the datastores
that support disk-level thin provisioning.
This procedure assumes that you are creating a new virtual machine. For information, see the vSphere Virtual
Machine Administration documentation.
Procedure
1
Right-click any inventory object that is a valid parent object of a virtual machine, such as a data center,
folder, cluster, resource pool, or host, and select New Virtual Machine.
2
Select Create a new virtual machine and click Next.
3
Follow the steps required to create a virtual machine.
4
On the Customize Hardware page, click the Virtual Hardware tab.
5
Click the New Hard Disk triangle to expand the hard disk options.
6
(Optional) Adjust the default disk size.
With a thin virtual disk, the disk size value shows how much space is provisioned and guaranteed to
the disk. At the beginning, the virtual disk might not use the entire provisioned space and the actual
storage usage value could be less than the size of the virtual disk.
7
Select Thin Provision for Disk Provisioning.
8
Finish virtual machine creation.
You created a virtual machine with a disk in thin format.
What to do next
If you created a virtual disk in the thin format, you can later inflate it to its full size.
View Virtual Machine Storage Resources
You can view how datastore storage space is allocated for your virtual machines.
Storage Usage shows how much datastore space is occupied by virtual machine files, including
configuration and log files, snapshots, virtual disks, and so on. When the virtual machine is running, the
used storage space also includes swap files.
For virtual machines with thin disks, the actual storage usage value might be less than the size of the virtual
disk.
Procedure
1
In the vSphere Web Client, browse to the virtual machine.
2
Double-click the virtual machine and click the Summary tab.
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3
Review the storage usage information in the upper right area of the Summary tab.
Determine the Disk Format of a Virtual Machine
You can determine whether your virtual disk is in thick or thin format.
Procedure
1
In the vSphere Web Client, browse to the virtual machine.
2
Right-click the virtual machine and select Edit Settings.
3
Click the Virtual Hardware tab.
4
Click the Hard Disk triangle to expand the hard disk options.
The Type text box shows the format of your virtual disk.
What to do next
If your virtual disk is in the thin format, you can inflate it to its full size.
Inflate Thin Virtual Disks
If you created a virtual disk in the thin format, you can convert the thin disk to a virtual disk in thick
provision format.
You use the datastore browser to inflate the virtual disk.
Prerequisites
n
Make sure that the datastore where the virtual machine resides has enough space.
n
Make sure that the virtual disk is thin.
n
Remove snapshots.
n
Power off your virtual machine.
Procedure
1
Navigate to the folder of the virtual disk you want to inflate.
a
In the vSphere Web Client, browse to the virtual machine.
b
Click the Datastores tab.
The datastore that stores the virtual machine files is listed.
c
Select the datastore and click the Browse Files icon (
).
The datastore browser displays contents of the datastore.
2
Expand the virtual machine folder and browse to the virtual disk file that you want to convert.
The file has the .vmdk extension and is marked with the virtual disk (
3
) icon.
Right-click the virtual disk file and select Inflate.
Note The option might not be available if the virtual disk is thick or when the virtual machine is
running.
The inflated virtual disk occupies the entire datastore space originally provisioned to it.
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Handling Datastore Over-Subscription
Because the provisioned space for thin disks can be greater than the committed space, a datastore oversubscription can occur, which results in the total provisioned space for the virtual machine disks on the
datastore being greater than the actual capacity.
Over-subscription can be possible because usually not all virtual machines with thin disks need the entire
provisioned datastore space simultaneously. However, if you want to avoid over-subscribing the datastore,
you can set up an alarm that notifies you when the provisioned space reaches a certain threshold.
For information on setting alarms, see the vCenter Server and Host Management documentation.
If your virtual machines require more space, the datastore space is allocated on a first come first served
basis. When the datastore runs out of space, you can add more physical storage and increase the datastore.
See “Increase VMFS Datastore Capacity,” on page 165.
ESXi and Array Thin Provisioning
You can use thin-provisioned storage arrays with ESXi.
The ESXi host integrates with block-based storage and performs these tasks:
n
The host can recognize underlying thin-provisioned LUNs and monitor their space usage to avoid
running out of physical space. As your VMFS datastore grows or if you use Storage vMotion to migrate
virtual machines to a thin-provisioned LUN, the host communicates with the LUN and warns you
about breaches in physical space and about out-of-space conditions.
n
The host can automatically issue the T10 unmap command from VMFS6 and VM guest operating systems
to reclaim unused space from the array. VMFS5 supports manual space reclamation.
Note ESXi does not support enabling and disabling of thin provisioning on a storage device.
Requirements
To use the thin provisioning reporting and space reclamation features, follow these requirements:
n
Use an appropriate ESXi version.
Table 24‑1. ESXi versions and thin provisioning support
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Supported thin provisioning components
ESXi 6.0 and earlier
ESXi 6.5
Thin provisioning
Yes
Yes
Unmap command originating form VMFS
Manual for VMFS5. Use
esxcli storage vmfs
unmap.
Automatic for VMFS6
Unmap command originating from guest OS
Yes. Limited support.
Yes (VMFS6)
Use storage systems that support T10-based vSphere Storage APIs - Array Integration (VAAI),
including thin provisioning and space reclamation. For information, contact your storage provider and
check the VMware Compatibility Guide.
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Space Usage Monitoring
The thin provision integration functionality helps you to monitor the space usage on thin-provisioned LUNs
and to avoid running out of space.
The following sample flow demonstrates how the ESXi host and the storage array interact to generate
breach of space and out-of-space warnings for a datastore with underlying thin-provisioned LUN. The same
mechanism applies when you use Storage vMotion to migrate virtual machines to the thin-provisioned
LUN.
1
Using storage-specific tools, your storage administrator provisions a thin LUN and sets a soft threshold
limit that, when reached, triggers an alert. This step is vendor-specific.
2
Using the vSphere Web Client, you create a VMFS datastore on the thin-provisioned LUN. The
datastore spans the entire logical size that the LUN reports.
3
As the space used by the datastore increases and reaches the specified soft threshold, the following
actions take place:
a
The storage array reports the breach to your host.
b
Your host triggers a warning alarm for the datastore.
You can contact the storage administrator to request more physical space or use Storage vMotion to
evacuate your virtual machines before the LUN runs out of capacity.
4
If no space is left to allocate to the thin-provisioned LUN, the following actions take place:
a The storage array reports out-of-space condition to your host.
Caution In certain cases, when a LUN becomes full, it might go offline or get unmapped from the
host.
b
The host pauses virtual machines and generates an out-of-space alarm.
You can resolve the permanent out-of-space condition by requesting more physical space from the
storage administrator.
Identify Thin-Provisioned Storage Devices
Use the esxcli command to verify whether a particular storage device is thin-provisioned.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
Run the esxcli --server=server_name storage core device list -d=device_ID command.
The following thin provisioning status indicates that the storage device is thin-provisioned.
# esxcli --server=server_name storage core device list -d naa.XXXXXXXXXXXX4c
naa.XXXXXXXXXXXX4c
Display Name: XXXX Fibre Channel Disk(naa.XXXXXXXXXXXX4c)
Size: 20480
Device Type: Direct-Access
Multipath Plugin: NMP
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Thin Provisioning Status: yes
Attached Filters: VAAI_FILTER
VAAI Status: supported
---------------------
An unknown status indicates that a storage device is thick.
Note Some storage systems present all devices as thin-provisioned no matter whether the devices are thin
or thick. Their thin provisioning status is always yes. For details, check with your storage vendor.
Storage Space Reclamation
ESXi supports the space reclamation command, also called SCSI unmap command, that originates from a
VMFS datastore or a VM guest operating system. The command helps thin-provisioned storage arrays to
reclaim unused space from the VMFS datastore and thin virtual disks on the datastore. The VMFS6
datastore can send the space reclamation command automatically. With the VMFS5 datastore, you can
manually reclaim storage space.
You free storage space inside the VMFS datastore when you delete or migrate the VM, consolidate a
snapshot, and so on. Inside the virtual machine, storage space is freed when you delete files on the thin
virtual disk. These operations leave blocks of unused space on the storage array. However, when the array is
not aware that the data was deleted from the blocks, the blocks remain allocated by the array until the
datastore releases them. VMFS uses the SCSI unmap command to indicate to the array that the storage
blocks contain deleted data, so that the array can unallocate these blocks.
ESXi host
Storage Array
VMFS Datastore
VMs
Physical Disk
Blocks
The command can also originate directly from the guest operating system. Both VMFS5 and VMFS6
datastores can provide support to the unmap command that proceeds from the guest operating system.
However, the level of support is limited on VMFS5.
Depending on the type of your VMFS datastore, you use different methods to configure space reclamation
for the datastore and your virtual machines.
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Watch the following video to learn more about how space reclamation works.
Space Reclamation with VMFS in vSphere 6.5
(http://link.brightcove.com/services/player/bcpid2296383276001?
bctid=ref:video_space_reclamation_vmfs)
n
Space Reclamation Requests from VMFS Datastores on page 294
Deleting or removing files from a VMFS datastore frees space within the file system. This free space is
mapped to a storage device until the file system releases or unmaps it. ESXi supports reclamation of
free space, which is also called the unmap operation.
n
Space Reclamation Requests from Guest Operating Systems on page 297
ESXi supports the unmap commands issued directly from a guest operating system to reclaim storage
space. The level of support and requirements depend on the type of datastore where your virtual
machine resides.
Space Reclamation Requests from VMFS Datastores
Deleting or removing files from a VMFS datastore frees space within the file system. This free space is
mapped to a storage device until the file system releases or unmaps it. ESXi supports reclamation of free
space, which is also called the unmap operation.
The operation enables the storage array to reclaim unused free space. Unmapped space can be repurposed
for other storage allocation requests and needs.
Asynchronous Reclamation of Free Space on VMFS6 Datastore
On VMFS6 datastores, ESXi supports automatic asynchronous reclamation of free space. VMFS6 can
automatically issue the unmap command to release free storage space in background on thin-provisioned
storage arrays that support unmap operations.
Asynchronous unmap processing has several advantages:
n
Unmap requests are sent at a constant rate, which helps to avoid any instant load on the backing array.
n
Freed regions are batched and unmapped together.
n
Unmap processing and truncate I/O paths are disconnected, so I/O performance is not impacted.
For VMFS6 datastores, you can configure the following space reclamation parameters at datastore creation
time.
Space reclamation
granularity
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Granularity defines the minimum size of a released space sector that
underlying storage can reclaim. Storage cannot reclaim those sectors that are
smaller in size than the specified granularity.
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For VMFS6, reclamation granularity equals the block size. When you specify
the block size as 1 MB, the granularity is also 1 MB. Storage sectors of the size
smaller than 1 MB are not reclaimed.
Note Certain storage arrays recommend optimal unmap granularity. If the
recommended unmap granularity is greater than 1 MB, for example 16 MB,
ESXi does not support automatic unmap processing on these arrays. On the
arrays with the optimal granularity of 1 MB and less, the automatic unmap
operation is supported if the granularity is a factor of 1 MB. For example, 1
MB is divisible by 512 bytes, 4 K, 64 K, and so on.
Space reclamation
priority
This parameter defines the rate at which the space reclamation operation is
performed. Typically, VMFS6 can send the unmap commands either in bursts
or sporadically depending on the workload and configuration. When you
create a VMFS6 datastore, you can specify one of the following options.
n
None. Disables the unmap operations for the datastore. The option is
configurable through the vSphere Web Client.
n
Low (default). Sends the unmap command at a less frequent rate. The
option is configurable through the vSphere Web Client.
Manual Reclamation of Free Space on VMFS5 Datastore
VMFS5 and earlier file systems do not unmap free space automatically, but you can use the esxcli storage
vmfs unmap command to reclaim space manually. When you use the command, keep in mind that it might
send many unmap requests at a time, which can lock some of the resources during this operation.
Configure Space Reclamation for a VMFS6 Datastore
When you create a VMFS6 datastore, you can modify the default parameters for automatic space
reclamation, granularity and priority, or disable space reclamation for your VMFS6 datastore.
Procedure
1
In the vSphere Web Client navigator, select Global Inventory Lists > Datastores.
2
Click the New Datastore icon.
3
Follow the steps required to create a VMFS6 datastore.
4
On the Partition configuration page, specify the space reclamation parameters.
The parameters define granularity and the rate at which space reclamation operations are performed.
You can also use this page to disable space reclamation for the datastore.
Option
Description
Block size
The block size on a VMFS datastore defines the maximum file size and the
amount of space the file occupies. VMFS6 supports the block size of 1 MB.
Space reclamation granularity
Specify granularity for the unmap operation. Unmap granularity equals
the block size, which is 1 MB.
Storage sectors of the size smaller than 1 MB are not reclaimed.
Space reclamation priority
Select one of the following options.
Low (default). Process the unmap operations at a low rate.
n None. Select this option if you want to disable the space reclamation
operations for the datastore.
n
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After you enable space reclamation, your VMFS6 can automatically release specified blocks of unused space
to the storage array.
Change Space Reclamation Priority
Space reclamation priority defines how blocks deleted from a VMFS6 datastores are reclaimed on a LUN
backing the datastore. By default, the LUN performs the space reclamation operation at a low rate. You can
modify the default setting to disable the operation for the datastore.
Procedure
1
Browse to the datastore in the vSphere Web Client navigator.
2
Select Edit Space Reclamation from the right-click menu.
3
Modify the space reclamation setting.
4
Option
Description
None
Select this option if you want to disable the space reclamation operations
for the datastore.
Low (default)
Reclaim space at a low rate.
Click OK to save the new settings.
The modified value for the space reclamation priority appears on the General page for the datastore.
Verify Configuration for Automatic Space Reclamation
After you configure or edit space reclamation parameters for a VMFS6 datastore, you can review your
configuration.
Procedure
1
Navigate to the datastore.
2
Click the Configure tab.
3
Click General, and verify the space reclamation settings.
a
Under Properties, expand File system and review the value for the space reclamation granularity.
b
Under Space Reclamation, review the setting for the space reclamation priority.
Example: Obtaining Parameters for VMFS6 Space Reclamation
You can also use the esxcli storage vmfs reclaim config get -l=VMFS_label|-u=VMFS_uuid command to
obtain information for the space reclamation configuration.
# esxcli storage vmfs reclaim config get -l my_datastore
Reclaim Granularity: 1048576 Bytes
Reclaim Priority: low
Manually Reclaim Accumulated Storage Space
On VMFS datastores, where automatic space reclamation is not supported, you can use the esxcli
command to manually reclaim unused storage space.
In the procedure, --server=server_name specifies the target server. The specified target server prompts you
for a user name and password. Other connection options, such as a configuration file or session file, are
supported. For a list of connection options, see Getting Started with vSphere Command-Line Interfaces.
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Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
Procedure
u
To reclaim unused storage blocks on the thin-provisioned device, run the following command:
esxcli --server=server_name storage vmfs unmap
The command takes these options:
Option
Description
-l|--volume-label=volume_label
The label of the VMFS volume to unmap. This is a mandatory argument. If
you specify this argument, do not use -u|--volume-uuid=volume_uuid.
-u|--volume-uuid=volume_uuid
The UUID of the VMFS volume to unmap. This is a mandatory argument.
If you specify this argument, do not use
-l|--volume-label=volume_label.
-n|--reclaim-unit=number
Number of VMFS blocks to unmap per iteration. This is an optional
argument. If it is not specified, the command uses the default value of 200.
What to do next
Important For additional details, see the VMware knowledge base article at
http://kb.vmware.com/kb/2014849.
Space Reclamation Requests from Guest Operating Systems
ESXi supports the unmap commands issued directly from a guest operating system to reclaim storage space.
The level of support and requirements depend on the type of datastore where your virtual machine resides.
Inside a virtual machine, storage space is freed when, for example, you delete files on the thin virtual disk.
The guest operating system notifies VMFS about freed space by sending the unmap command. The unmap
command sent from the guest operating system releases space within the VMFS datastore. The command
then proceeds to the array, so that the array can reclaim the freed blocks of space.
Space Reclamation for VMFS6 Virtual Machines
VMFS6 generally supports automatic space reclamation requests that generate from the guest operating
systems, and passes these requests to the array. Many guest operating systems can send the unmap
command and do not require any additional configuration. The guest operating systems that do not support
automatic unmaps might require user intervention. For information about the guest operating systems that
support automatic space reclamation on VMFS6, contact your vendor.
Generally, the guest operating systems send the unmap commands based on the unmap granularity they
advertise. For details, see documentation provided with your guest operating system.
VMFS6 processes the unmap request from the guest operating system only when the space to reclaim is
equal to 1 MB or a multiple of 1 MB. If the space is less than 1 MB or is not aligned to 1 MB, the unmap
requests are not processed.
Space Reclamation for VMFS5 Virtual Machines
Typically, the unmap command that generates from the guest operation system on VMFS5 cannot be passed
directly to the array. You must run the esxcli storage vmfs unmap command to trigger unmaps for the
array.
However, for a limited number of the guest operating systems, VMFS5 supports the automatic space
reclamation requests.
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To send the unmap requests from the guest operating system to the array, the virtual machine must meet the
following prerequisites:
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n
The virtual disk must be thin-provisioned.
n
Virtual machine hardware must be of version 11 (ESXi 6.0) or later.
n
The advanced setting EnableBlockDelete must be set to 1.
n
The guest operating system must be able to identify the virtual disk as thin.
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Using vmkfstools
vmkfstools is one of the ESXi Shell commands for managing VMFS volumes, storage devices, and virtual
disks. You can perform many storage operations using the vmkfstools command. For example, you can
create and manage VMFS datastores on a physical partition, or manipulate virtual disk files, stored on
VMFS or NFS datastores.
Note After you make a change using the vmkfstools, the vSphere Web Client might not be updated
immediately. Use a refresh or rescan operation from the client.
For more information on the ESXi Shell, see Getting Started with vSphere Command-Line Interfaces.
This chapter includes the following topics:
n
“vmkfstools Command Syntax,” on page 299
n
“vmkfstools Options,” on page 300
vmkfstools Command Syntax
Generally, you do not need to log in as the root user to run the vmkfstools commands. However, some
commands, such as the file system commands, might require the root user login.
The vmkfstools command supports the following command syntax:
vmkfstools options target.
Target specifies a partition, device, or path to apply the command option to.
Table 25‑1. vmkfstools command arguments
Argument
Description
options
One or more command-line options and associated arguments that you use to
specify the activity for vmkfstools to perform, for example, choosing the disk
format when creating a new virtual disk.
After entering the option, specify a target on which to perform the operation.
Target can indicate a partition, device, or path.
partition
Specifies disk partitions. This argument uses a disk_ID:P format, where disk_ID
is the device ID returned by the storage array and P is an integer that represents
the partition number. The partition digit must be greater than zero (0) and
should correspond to a valid VMFS partition.
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Table 25‑1. vmkfstools command arguments (Continued)
Argument
Description
device
Specifies devices or logical volumes. This argument uses a path name in the
ESXi device file system. The path name begins with /vmfs/devices, which is
the mount point of the device file system.
Use the following formats when you specify different types of devices:
n
path
/vmfs/devices/disks for local or SAN-based disks.
n
/vmfs/devices/lvm for ESXi logical volumes.
n
/vmfs/devices/generic for generic SCSI devices.
Specifies a VMFS file system or file. This argument is an absolute or relative
path that names a directory symbolic link, a raw device mapping, or a file
under /vmfs.
n To specify a VMFS file system, use this format:
/vmfs/volumes/file_system_UUID
or
n
/vmfs/volumes/file_system_label
To specify a file on a VMFS datastore, use this format:
/vmfs/volumes/file_system_label|
file_system_UUID/[dir]/myDisk.vmdk
You do not need to enter the entire path if the current working directory is
the parent directory of myDisk.vmdk.
vmkfstools Options
The vmkfstools command has several options. Some of the options are suggested for advanced users only.
The long and single-letter forms of the options are equivalent. For example, the following commands are
identical.
vmkfstools --createfs vmfs6 --blocksize 1m disk_ID:P
vmkfstools -C vmfs6 -b 1m disk_ID:P
-v Suboption
The -v suboption indicates the verbosity level of the command output.
The format for this suboption is as follows:
-v --verbose number
You specify the number value as an integer from 1 through 10.
You can specify the -v suboption with any vmkfstools option. If the output of the option is not suitable for
use with the -v suboption, vmkfstools ignores -v.
Note Because you can include the -v suboption in any vmkfstools command line, -v is not included as a
suboption in the option descriptions.
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File System Options
File system options allow you to create and manage VMFS datastores. These options do not apply to NFS.
You can perform many of these tasks through the vSphere Web Client.
Listing Attributes of a VMFS Datastore
Use the vmkfstools command to list attributes of a VMFS datastore.
-P|--queryfs
-h|--humanreadable
When you use this option on any file or directory that resides on a VMFS datastore, the option lists the
attributes of the specified datastore. The listed attributes typically include the file system label, the number
of extents for the datastore, the UUID, and a list of the devices where each extent resides.
Note If any device backing VMFS file system goes offline, the number of extents and available space
change accordingly.
You can specify the -h|--humanreadable suboption with the -P option. If you do so, vmkfstools lists the
capacity of the volume in a more readable form.
Example: Example of Listing VMFS Attributes
~ vmkfstools -P -h /vmfs/volumes/my_vmfs
VMFS-5.81 (Raw Major Version: 14) file system spanning 1 partitions.
File system label (if any): my_vmfs
Mode: public
Capacity 99.8 GB, 97.5 GB available, file block size 1 MB, max supported file size 62.9 TB
UUID: 571fe2fb-ec4b8d6c-d375-XXXXXXXXXXXX
Partitions spanned (on "lvm"):
eui.3863316131XXXXXX:1
Is Native Snapshot Capable: YES
Creating a VMFS Datastore or a Scratch Partition
Use the vmkfstools command to create a VMFS datastore or a scratch partition.
-C|--createfs [vmfs5|vmfs6|vfat]
This option creates the VMFS datastore on the specified SCSI partition, such as disk_ID:P. The partition
becomes the head partition of the datastore. For VMFS5 and VMFS6, the only available block size is 1 MB.
You can also use the option ti create a
You can specify the following suboptions with the -C option.
n
-S|--setfsname - Define the volume label of the VMFS datastore you are creating. Use this suboption
only with the -C option. The label you specify can be up to 128 characters long and cannot contain any
leading or trailing blank spaces.
Note vCenter Server supports the 80 character limit for all its entities. If a datastore name exceeds this
limit, the name gets shortened when you add this datastore to vCenter Server.
After you define a volume label, you can use it whenever you specify the VMFS datastore for the
vmkfstools command. The volume label appears in listings generated for the ls -l command and as a
symbolic link to the VMFS volume under the /vmfs/volumes directory.
To change the VMFS volume label, use the ln -sf command. Use the following as an example:
ln -sf /vmfs/volumes/UUID /vmfs/volumes/datastore
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datastore is the new volume label to use for the UUID VMFS.
Note If your host is registered with vCenter Server, any changes you make to the VMFS volume label
get overwritten by vCenter Server. This operation guarantees that the VMFS label is consistent across all
vCenter Server hosts.
n
-Y|--unmapGranularity #[bBsSkKmMgGtT] - This suboption applies to VMFS6 only. Define granularity
for the unmap operation. The default granularity is 1 MB. As with the block size, enter the unit type.
n
-O|--unmapPriority <none|low|medium|high> - This suboption applies to VMFS6 only. Define the
priority for the unmap operation.
Example: Example for Creating a VMFS File System
This example illustrates creating a VMFS6 datastore named my_vmfs on the naa.ID:1 partition.
~ vmkfstools -C vmfs6 -S my_vmfs /vmfs/devices/disks/naa.ID:1
Extending an Existing VMFS Datastore
Use the vmkfstools command to add an extent to a VMFS datastore.
This option extends the VMFS datastore with the specified head partition by spanning it across the partition
specified by span_partition.
-Z|--spanfs span_partition head_partition
You must specify the full path name for the head and span partitions, for
example /vmfs/devices/disks/disk_ID:1. Each time you use this option, you add a new extent to the VMFS
datastore, so that the datastore spans multiple partitions.
Caution When you run this option, you lose all data that previously existed on the SCSI device you
specified in span_partition.
Example: Example for Extending a VMFS Datastore
In this example, you extend the existing head partition of the VMFS datastore over a new partition.
~ vmkfstools -Z /vmfs/devices/disks/naa.disk_ID_2:1 /vmfs/devices/disks/naa.disk_ID_1:1
The extended datastore spans two partitions—naa.disk_ID_1:1 and naa.disk_ID_2:1. In this example,
naa.disk_ID_1:1 is the name of the head partition.
Growing an Existing Extent
Instead of adding a new extent to a VMFS datastore, you can grow an existing extent using the vmkfstools -
G command.
Use the following option to increase the size of a VMFS datastore after the underlying storage had its
capacity increased.
-G|--growfs device device
This option grows an existing VMFS datastore or its extent. For example,
vmkfstools --growfs /vmfs/devices/disks/disk_ID:1 /vmfs/devices/disks/disk_ID:1
Upgrading a VMFS Datastore
If you use a VMFS3 datastore, you must upgrade it to VMFS5.
When upgrading the datastore, use the following option:
-T|--upgradevmfs /vmfs/volumes/UUID
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The upgrade is a one-way process. After you have converted a VMFS3 datastore to VMFS5, you cannot
revert it back.
All hosts accessing the datastore must support VMFS5.
Virtual Disk Options
Virtual disk options allow you to set up, migrate, and manage virtual disks stored on your datastores. You
can also perform most of these tasks through the vSphere Web Client.
Supported Disk Formats
When you create or clone a virtual disk, you can use the -d|--diskformat suboption to specify the format for
the disk.
Choose from the following formats:
n
zeroedthick (default) – Space required for the virtual disk is allocated during creation. Any data
remaining on the physical device is not erased during creation, but is zeroed out on demand on first
write from the virtual machine. The virtual machine does not read stale data from disk.
n
eagerzeroedthick – Space required for the virtual disk is allocated at creation time. In contrast to
zeroedthick format, the data remaining on the physical device is zeroed out during creation. It might
take much longer to create disks in this format than to create other types of disks.
n
thin – Thin-provisioned virtual disk. Unlike with the thick format, space required for the virtual disk is
not allocated during creation, but is supplied, zeroed out, on demand.
n
rdm:device – Virtual compatibility mode raw disk mapping.
n
rdmp:device – Physical compatibility mode (pass-through) raw disk mapping.
n
2gbsparse – A sparse disk with the maximum extent size of 2 GB. You can use disks in this format with
hosted VMware products, such as VMware Fusion. However, you cannot power on the sparse disk on
an ESXi host unless you first re-import the disk with vmkfstools in a compatible format, such as thick
or thin.
Disk Formats on NFS Datastores
The only disk formats you can use for NFS are thin, thick, zeroedthick, and 2gbsparse.
Thick, zeroedthick, and thin formats usually behave the same because the NFS server and not the ESXi host
determines the allocation policy. The default allocation policy on most NFS servers is thin. However, on
NFS servers that support Storage APIs - Array Integration, you can create virtual disks in zeroedthick
format. The reserve space operation enables NFS servers to allocate and guarantee space.
For more information on array integration APIs, see Chapter 23, “Storage Hardware Acceleration,” on
page 277.
Creating a Virtual Disk
Use the vmkfstools command to create a virtual disk.
-c|--createvirtualdisk size[bB|sS|kK|mM|gG]
-d|--diskformat [thin|zeroedthick|eagerzeroedthick]
-W|--objecttype [file|vsan|vvol]
--policyFile fileName
This option creates a virtual disk at the specified path on a datastore. Specify the size of the virtual disk.
When you enter the value for size, you can indicate the unit type by adding a suffix of k (kilobytes), m
(megabytes), or g (gigabytes). The unit type is not case-sensitive. vmkfstools interprets either k or K to mean
kilobytes. If you do not specify a unit type, vmkfstools defaults to bytes.
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You can specify the following suboptions with the -c option.
n
-d|--diskformat specifies disk formats.
n
-W|--objecttype specifies whether the virtual disk is a file on a VMFS or NFS datastore, or an object on
a Virtual SAN or Virtual Volumes datastore.
n
--policyFile fileName specifies VM storage policy for the disk.
Example: Example for Creating a Virtual Disk
This example shows how to create a two-gigabyte virtual disk file named disk.vmdk. You create the disk on
the VMFS datastore named myVMFS. The disk file represents an empty virtual disk that virtual machines can
access.
vmkfstools -c 2048m /vmfs/volumes/myVMFS/disk.vmdk
Initializing a Virtual Disk
Use the vmkfstools command to initialize a virtual disk.
-w|--writezeros
This option cleans the virtual disk by writing zeros over all its data. Depending on the size of your virtual
disk and the I/O bandwidth to the device hosting the virtual disk, completing this command might take a
long time.
Caution When you use this command, you lose any existing data on the virtual disk.
Inflating a Thin Virtual Disk
Use the vmkfstools command to inflate a thin virtual disk.
-j|--inflatedisk
This option converts a thin virtual disk to eagerzeroedthick, preserving all existing data. The option
allocates and zeroes out any blocks that are not already allocated.
Converting a Zeroedthick Virtual Disk to an Eagerzeroedthick Disk
Use the vmkfstools command to convert any zeroedthick virtual disk to an eagerzeroedthick disk.
-k|--eagerzero
While performing the conversion, this option preserves any data on the virtual disk.
Follow this example:
vmkfstools --eagerzero /vmfs/volumes/myVMFS/VMName/disk.vmdk
Removing Zeroed Blocks
Use the vmkfstools command to remove zeroed blocks.
-K|--punchzero
This option deallocates all zeroed out blocks and leaves only those blocks that were allocated previously and
contain valid data. The resulting virtual disk is in thin format.
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Deleting a Virtual Disk
Use the vmkfstools command to delete a virtual disk file at the specified path on the VMFS volume.
Use the following option:
-U|--deletevirtualdisk
Renaming a Virtual Disk
Use the vmkfstools command to rename a virtual disk file at the specified path on the VMFS volume.
You must specify the original file name or file path oldName and the new file name or file path newName.
-E|--renamevirtualdisk oldName newName
Cloning or Converting a Virtual Disk or RDM
Use the vmkfstools command to create a copy of a virtual disk or raw disk you specify.
A non-root user is not allowed to clone a virtual disk or an RDM. You must specify the original file name or
file path oldName and the new file name or file path newName.
-i|--clonevirtualdisk oldName newName
-d|--diskformat [thin|zeroedthick|eagerzeroedthick|rdm:device|rdmp:device|2gbsparse]
-W|--objecttype [file|vsan|vvol]
--policyFile fileName
-N|--avoidnativeclone
Use the following suboptions to change corresponding parameters for the copy you create.
n
-d|--diskformat specifies disk formats.
n
-W|--objecttype specifies whether the virtual disk is a file on a VMFS or NFS datastore, or an object on
a Virtual SAN or Virtual Volumes datastore.
n
--policyFile fileName specifies VM storage policy for the disk.
By default, ESXi uses its native methods to perform the cloning operations. If your array supports the
cloning technologies, you can off-load the operations to the array. Specify the -N|--avoidnativeclone option
to avoid the ESXi native cloning.
Example: Example for Cloning or Converting a Virtual Disk
This example illustrates cloning the contents of a master virtual disk from the templates repository to a
virtual disk file named myOS.vmdk on the myVMFS file system.
vmkfstools -i /vmfs/volumes/myVMFS/templates/gold-master.vmdk /vmfs/volumes/myVMFS/myOS.vmdk
You can configure a virtual machine to use this virtual disk by adding lines to the virtual machine
configuration file, as in the following example:
scsi0:0.present = TRUE
scsi0:0.fileName = /vmfs/volumes/myVMFS/myOS.vmdk
If you want to convert the format of the disk, use the -d|--diskformat suboption.
This suboption is useful when you import virtual disks in a format not compatible with ESXi, for example
2gbsparse format. After you convert the disk, you can attach this disk to a new virtual machine you create in
ESXi.
For example:
vmkfstools -i /vmfs/volumes/myVMFS/templates/gold-master.vmdk /vmfs/volumes/myVMFS/myOS.vmdk
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Extending a Virtual Disk
After you create a virtual machine, you can use the vmkfstools command to extend the size of a disk
allocated to the virtual machine.
-X|--extendvirtualdisk newSize[bBsSkKmMgGtT]
Specify the newSize parameter adding an appropriate unit suffix. The unit type is not case-sensitive.
vmkfstools interprets either k or K to mean kilobytes. If you do not specify the unit type, vmkfstools defaults
to kilobytes.
The newSize parameter defines the entire new size, not just the increment you add to the disk.
For example, to extend a 4-g virtual disk by 1 g, enter: vmkfstools -X 5g disk name.
You can extend the virtual disk to the eagerzeroedthick format by using the -d eagerzeroedthick option.
When you use the -X option, the following considerations apply:
n
Do not extend the base disk of a virtual machine that has snapshots associated with it. If you do, you
can no longer commit the snapshot or revert the base disk to its original size.
n
After you extend the disk, you might need to update the file system on the disk. As a result, the guest
operating system recognizes the new size of the disk and is able to use it.
Upgrading Virtual Disks
This option converts the specified virtual disk file from ESX Server 2 formats to the ESXi format.
Use this option to convert virtual disks of type LEGACYSPARSE, LEGACYPLAIN, LEGACYVMFS,
LEGACYVMFS_SPARSE, and LEGACYVMFS_RDM.
-M|--migratevirtualdisk
Creating a Virtual Compatibility Mode Raw Device Mapping
Use the vmkfstools command to create a Raw Device Mapping (RDM) file on a VMFS volume and map a
raw LUN to this file. After this mapping is established, you can access the LUN as you would a normal
VMFS virtual disk. The file length of the mapping is the same as the size of the raw LUN it points to.
-r|--createrdm device
When specifying the device parameter, use the following format:
/vmfs/devices/disks/disk_ID:P
Example: Example for Creating a Virtual Compatibility Mode RDM
In this example, you create an RDM file named my_rdm.vmdk and map the disk_ID raw disk to that file.
vmkfstools -r /vmfs/devices/disks/disk_ID my_rdm.vmdk
You can configure a virtual machine to use the my_rdm.vmdk mapping file by adding the following lines to
the virtual machine configuration file:
scsi0:0.present = TRUE
scsi0:0.fileName = /vmfs/volumes/myVMFS/my_rdm.vmdk
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Creating a Physical Compatibility Mode Raw Device Mapping
Use the vmkfstools command to map a pass-through raw device to a file on a VMFS volume. This mapping
lets a virtual machine bypass ESXi SCSI command filtering when accessing its virtual disk. This type of
mapping is useful when the virtual machine needs to send proprietary SCSI commands, for example, when
SAN-aware software runs on the virtual machine.
-z|--createrdmpassthru device
After you establish this type of mapping, you can use it to access the raw disk just as you would any other
VMFS virtual disk.
When specifying the device parameter, use the following format:
/vmfs/devices/disks/disk_ID
For example,
vmkfstools -z /vmfs/devices/disks/disk_ID my_rdm.vmdk
Listing Attributes of an RDM
Use the vmkfstools command to list the attributes of a raw disk mapping. The attributes help you identify
the storage device to which your RDM files maps.
-q|--queryrdm my_rdm.vmdk
This option prints the name of the raw disk RDM. The option also prints other identification information,
like the disk ID, for the raw disk.
Example: Example of Listing RDM Attributes
# vmkfstools -q /vmfs/volumes/VMFS/my_vm/my_rdm.vmdk
Disk /vmfs/volumes/VMFS/my_vm/my_rdm.vmdk is a Passthrough Raw Device Mapping
Maps to: vml.020000000060050768019002077000000000000005323134352020
Displaying Virtual Disk Geometry
Use the vmkfstools command to get information about the geometry of a virtual disk.
-g|--geometry
The output is in the form: Geometry information C/H/S, where C represents the number of cylinders, H
represents the number of heads, and S represents the number of sectors.
Note When you import virtual disks from hosted VMware products to the ESXi host, you might see a disk
geometry mismatch error message. A disk geometry mismatch might also trigger problems when you load a
guest operating system or run a newly created virtual machine.
Checking and Repairing Virtual Disks
Use the vmkfstools command to check or repair a virtual disk if it gets corrupted.
-x|--fix [check|repair]
For example,
vmkfstools -x check /vmfs/volumes/my_datastore/my_disk.vmdk
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Checking Disk Chain for Consistency
Use the vmkfstools command to check the entire snapshot chain. You can determine if any of the links in the
chain are corrupted or any invalid parent-child relationships exist.
-e|--chainConsistent
Storage Device Options
Device options of the vmkfstools command allow you to perform administrative task for physical storage
devices.
Managing SCSI Reservations of LUNs
Use the vmkfstools command to reserve a SCSI LUN for exclusive use by the ESXi host. You can also release
a reservation so that other hosts can access the LUN, and reset a reservation, forcing all reservations from
the target to be released.
-L|--lock [reserve|release|lunreset|targetreset|busreset|readkeys|readresv] device
Caution Using the -L option can interrupt the operations of other servers on a SAN. Use the -L option
only when troubleshooting clustering setups.
Unless advised by VMware, never use this option on a LUN hosting a VMFS volume.
You can specify the -L option in several ways:
n
-L reserve – Reserves the specified LUN. After the reservation, only the server that reserved that LUN
can access it. If other servers attempt to access that LUN, a reservation error appears.
n
-L release – Releases the reservation on the specified LUN. Other servers can access the LUN again.
n
-L lunreset – Resets the specified LUN by clearing any reservation on the LUN and making the LUN
available to all servers again. The reset does not affect any of the other LUNs on the device. If another
LUN on the device is reserved, it remains reserved.
n
-L targetreset – Resets the entire target. The reset clears any reservations on all the LUNs associated
with that target and makes the LUNs available to all servers again.
n
-L busreset – Resets all accessible targets on the bus. The reset clears any reservation on all the LUNs
accessible through the bus and makes them available to all servers again.
n
-L readkeys – Reads the reservation keys registered with a LUN. Applies to SCSI-III persistent group
reservation functionality.
n
-L readresv – Reads the reservation state on a LUN. Applies to SCSI-III persistent group reservation
functionality.
When entering the device parameter, use the following format:
/vmfs/devices/disks/disk_ID:P
Breaking Device Locks
Use the vmkfstools command to break the device lock on a particular partition.
-B|--breaklock device
When entering the device parameter, use the following format:
/vmfs/devices/disks/disk_ID:P
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Chapter 25 Using vmkfstools
You can use this command when a host fails in the middle of a datastore operation, such as grow extent, add
extent, or resignaturing. When you issue this command, make sure that no other host is holding the lock.
VMware, Inc.
309
vSphere Storage
310
VMware, Inc.
Index
Symbols
B
* next to path 189
backups
considerations 32
third-party backup package 33
best practices
FCoE 46
storage containers 261
VVols performance 262
bidirectional CHAP 94
binding virtual volumes 243
BIOS, enabling for BFS 52
block devices 206
boot adapters 51
boot BIOS prompt, enabling for BFS 52
boot from DVD-ROM 51
boot from iSCSI SAN
configuring HBAs 104
configuring iSCSI settings 105
guidelines 103
hardware iSCSI 104
iBFT 105
preparing SAN 104
software iSCSI 105
boot from SAN
benefits 49
boot LUN considerations 50
configuring Emulex HBAs 52
configuring Qlogic HBAs 53
configuring storage 50
HBA requirements 50
host requirements 50
overview 49
preparing installation 50
requirements 50
Numerics
512e storage devices 144
512n storage devices 144
A
access control 66
accessing storage 24
active-active disk arrays 36, 40, 66, 70, 191
active-passive disk arrays, boot from SAN 50
adaptive scheme 30
adding, NFS storage 162
adding an ESXi host to an Active Directory
domain 159
advanced attributes, hosts 179
advanced settings
Disk.EnableNaviReg 60
Disk.MaxLUN 122
VMkernel.Boot.isPerFileSchedModelActive 200
all paths down event 122
all paths down 125, 126
allocations, LUN 40
allocations, LUN 70
APD
handling 125
Misc.APDHandlingEnable parameter 126
Misc.APDTimeout 126
with High Availability 127
See also all paths down event
applications, layered 31
applying tags to datastores 215
array integration, thin provisioning 291
array-based solution 31
asterisk next to path 189
ATS-only locking, upgrading 148
ATS-only upgrade
offline 148
online 148
prerequisites 148
ATS-only locking, downgrading to ATS
+SCSI 149
authentication 66, 94
automatic host registration, disabling 60
VMware, Inc.
C
CHAP
bidirectional 94
disabling 97
for discovery targets 96
for iSCSI initiators 95
for static targets 96
one-way 94
CHAP authentication 66, 94
CHAP authentication methods 94
311
vSphere Storage
claim rules 189
cloning storage policies 227
common data services, activating 273
compatibility modes
physical 206
virtual 206
configuration files, virtual machines 127
configuration parameters, virtual machines 127
configure a swap cache using a virtual flash
resource 133
configuring
dynamic discovery 73, 77, 79, 93
Flash Read Cache 138
configuring DNS for NFS 4.1 159
copying files 170
core dump files
creating 175
deleting 177
creating tags 215
creating VVol datastores 162, 251
current multipathing state 190
D
data digests 67
datastore browser, downloading files 170
datastores
adding extents 165
administrative operations 166
configuring on NFS volumes 162
copying files on 170
creating 160
displaying 21
displaying for a parent object 23
increasing capacity 165
managing duplicate 163
mounting 163
moving files on 171
NFS 141
paths 190
renaming 167
renaming files on 171
review information 22
storage over-subscription 291
unmounting 167
VMFS 141
VVols 162, 251
default storage policies
provided by VMware 216
user-created 217
default storage policy, changing 217
deleting storage policy 226
dependent iSCSI, networking 81
312
dependent hardware iSCSI
and associated NICs 76
configuration 75
configuration workflow 74
considerations 74
device locks, breaking 308
device loss, unplanned 122, 125
diagnostic partition
configuring 174
verifying 175
diagnostic partitions 39, 70
disaster recovery 28
discovery
address 93
dynamic 73, 77, 79, 93
disk chain, consistency 308
disk arrays
active-active 40, 70, 191
active-passive 40, 70, 191
disk formats
thick provisioned 288
thin provisioned 288
disk mirroring 173
disk timeout 185
Disk.EnableNaviReg 60
Disk.MaxLUN, and Protocol Endpoints 122
disks
format 290
inflate 171, 290
DRS support for virtual flash 138
dump partitions 39, 70
DVD-ROM, booting from 51
dynamic discovery, configuring 73, 77, 79, 93
dynamic discovery addresses 93
dynamic disks 173
E
editing storage policies 227
educational support 9
enabling Kerberos users 159
erasing, storage devices 128
esxcli commands, and
isPerFileSchedModelActive 201
esxcli commands, obtaining VMFS locking
information 147
ESXi host, and multiple storage arrays 29
ESXi NFS protocols 150
EUI 64
extents
adding to datastore 165
growing 165
VMware, Inc.
Index
F
failover
I/O delay 184
transparent 36, 66
failover paths, status 189
fault domains 258
FC HBA setup 40
FC SAN
accessing 37
hardware requirements 39
FCoE, best practices 46
FCoE adapters 45
Fibre Channel, concepts 35
Fibre Channel over Ethernet 45
Fibre Channel SAN
best practices 59
preventing problems 59
file-based (VMFS) solution 32
files
copying 170
moving 171
FIP 46
firewall, NFS client 155
Fixed path policy 188, 191
flash device, monitoring 132
flash devices
best Practices 132
estimating lifetime 132
marking 131
using with vSphere 130
Flash Read Cache
migrating virtual machines 139
migration settings 139
flash virtual disks 130
G
GPT 18, 117
GPT format 144
guidelines, NFS storage 152
H
HA support for virtual flash 138
hardware acceleration
about 277
benefits 277
block storage 278
deleting claim rules 283
enabling 279
NAS 283
NAS status 285
requirements 278
status 278
support details 280
VMware, Inc.
hardware acceleration, considerations 286
hardware iSCSI, and failover 182
hardware iSCSI initiators
configuring 71
installing 72
setting up discovery addresses 93
viewing 72
hardware iSCSI adapters
dependent 65
independent 65
HBAs
queue depth 39
setup 40
static load balancing 40
header digests 67
high-tier storage 30
host registration, disabling 60
host cache, swapping to 135
host cache, configuring on a VMFS
datastore 135
host cache, configuring with virtual flash
resource 136
host configuration, advanced settings 60
host-based failover 181
hosts
advanced attributes 179
and FC SAN 35
I
I/O filters
about 265
and storage providers 267
and VFFS volume 268
and virtual flash resource 268
and VM migration 275
classes 266
components 266
considerations 275
deploying 274
description 265
Flash Read Cache 270
installation requirements 268
installing on a cluster 269
storage providers 270
uninstalling 274
upgrading 274
virtual disk enablement 271
virtual machine storage policies 271
workflow 269
I/O delay 70, 184
iBFT 105
iBFT iSCSI boot
booting an ESXi host 108
313
vSphere Storage
changing boot sequence 107
installing an ESXi host 107
limitations 106
networking best practices 108
setting up ESXi 106
troubleshooting 109
IDE 14
independent hardware iSCSI adapters, change
IP address 73
installation
preparing for boot from SAN 50
steps 40
IP address 64
IQN 64
iSCSI 15
iSCSI initiators
configuring CHAP 95
configuring advanced parameters 99
hardware 71
setting up CHAP parameters 94
iSCSI networking
binding adapters 90
changing policy 89
creating a VMkernel interface 88
managing 91
port binding details 90
troubleshooting 91
iSCSI SAN
accessing 68
best practices 111
boot 103
concepts 63
preventing problems 111
iSCSI adapter, modifying general properties 72,
76, 79, 81
iSCSI adapters
about 69
advanced parameters 98
hardware 65
software 65
iSCSI alias 64
iSCSI boot, iBFT 105
iSCSI Boot Firmware Table, See iBFT
iSCSI boot parameters, configuring 107
iSCSI names, conventions 64
iSCSI port binding, considerations 84
iSCSI ports 64
iSCSI SAN restrictions 70
iSCSI sessions
adding for a target 100
displaying 100
managing 99
removing 101
314
J
jumbo frames
enabling for dependent hardware iSCSI 92
enabling for independent hardware iSCSI 92
enabling for software iSCSI 92
using with iSCSI 91
K
Kerberos, configuring ESXi hosts 158
L
Layer 3 connections 156
layered applications 31
load balancing 28, 40
locations of virtual machines 30
locator LED
turning off 128
turning on 128
loss of network connection, troubleshooting 109
lower-tier storage 30
LUN decisions
adaptive scheme 30
predictive scheme 30
LUN masking 35
LUNs
allocations 40, 70
and VMFS datastores 39
changing number scanned 122
decisions 29
making changes and rescan 120
masking 197
multipathing policy 191
NPIV-based access 41
one VMFS volume per 70
setting multipathing policy 191
M
maintenance 28
marking, flash devices 131
masking LUNs 197
MBR 18, 117
MBR format 144
metadata, RDMs 206
metadata consistency, checking with VOMA 177
metadata updates 146
mid-tier storage 30
migrating virtual machines with Flash Read
Cache 139
migration
cross-host Storage vMotion 288
storage 288
Most Recently Used path policy 188, 191
mounting VMFS datastores 168
VMware, Inc.
Index
MPPs
displaying 194
See also multipathing plug-ins
MRU path policy 191
multipathing
active paths 189
broken paths 189
considerations 192
disabled paths 189
standby paths 189
viewing the current state of 189
multipathing claim rules
adding 195
deleting 197
multipathing plug-ins, path claiming 189
multipathing policy 191
multipathing state 190
N
N-Port ID Virtualization, See NPIV
NAA 64
NAS 15
NAS plug-ins
installing 284
uninstalling 284
upgrading 285
Native Multipathing Plug-In 186, 187
network connections, create 87
network adapters, configuring for iBFT iSCSI
boot 107
network performance 113
networking, configuring 71
NFS datastores
characteristics 21
maximum size 150
unmounting 167
NFS storage
adding 162
datastores 154
file locking 153
firewall 155
guidelines 152
hardware acceleration 154
multipathing 154
networking 153
server configuration 153
setting up 157
NFS 4.1
Kerberos credentials 156
Network Time Protocol 159
NFS client, firewall rule set 155
NFS clients, firewall ports 156
NFS storage, security 154
NICs, mapping to VMkernel 88
VMware, Inc.
NMP
I/O flow 188
path claiming 189
See also Native Multipathing Plug-In
NPIV
about 41
assigning WWNs 42
changing WWNs 43
limitations 42
requirements 41
O
one-way CHAP 94
P
partition mappings 206
passive disk arrays 40, 70, 191
path policies
Fixed 184, 188, 191
Most Recently Used 188, 191
MRU 191
Round Robin 188, 191
path claiming 189
path failover
and virtual machines 185
array-based 184
host-based 182
path failure rescan 120
path management 181
path selection policies, changing 191
Path Selection Plug-Ins 188
paths
disabling 192
masking 197
preferred 189
unmasking 198
PDL
with High Availability 127
See also permanent device loss
per file I/O scheduling
about 200
turning off 200
performance
checking Ethernet switch statistics 115
network 113
optimizing 60, 112
storage system 112
permanent device loss 122, 125
planned device removal 123
Pluggable Storage Architecture 186
pointer block cache
configuring 179
getting information 180
315
vSphere Storage
policy-driven storage 212
port binding 182
port redirection 184
Port_ID 36
predictive scheme 30
preferred path 189
protocol endpoints
editing paths 252
managing 251
PSA, See Pluggable Storage Architecture
PSPs, See Path Selection Plug-Ins
Q
Qlogic HBA BIOS, enabling for BFS 53
queue depth 70
R
RAID devices 206
raw device mapping, see RDM 203
RDM
advantages 204
and virtual disk files 207
dynamic name resolution 207
overview 203
physical compatibility mode 206
virtual compatibility mode 206
with clustering 207
RDMs
and snapshots 206
path management 209
reclaiming space 296
remove a virtual flash resource 134
renaming files 171
replicated VVols, replication groups 257
replication
considerations 259
requirements 256
workflow 259
requirements, boot from SAN 50
rescan
LUN creation 120
path masking 120
when path is down 120
rescanning
storage 121
storage adapter 121
resignature a VMFS datastore copy 164
resignaturing 163
restrictions 39
Round Robin path policy 188, 191
rule sets 218
316
S
SAN
backup considerations 32
benefits 27
requirements 39
specifics 28
SAN fabric 35
SAN management software 32
SAN storage performance, optimizing 60, 112
SAS 14
SATA 14
SATPs
adding rules 199
displaying 194
See also Storage Array Type Plug-Ins
scanning, changing number 122
scheduling queues 200
SCSI, vmkfstools 299
SCSI controllers 13
sense codes 122
server performance 61, 112
set up virtual flash resource 134
setup steps 40
snapshots
and virtual volumes 248
VMFS5 formats 149
VMFS6 formats 149
software iSCSI
and failover 182
diagnostic partition 174
networking 81
software FCoE
and VMkernel 46
activating adapters 47
booting 55
software FCoE boot
best practices 56
configuring parameters 56
ESXi installation 57
requirements 55
setting up 56
software FCoE installation, troubleshooting 57
software iSCSI adapter
configuring 77
disabling 80
software iSCSI initiator, enabling 78
software iSCSI boot, changing settings 109
software iSCSI initiators, setting up discovery
addresses 93
software iSCSI port binding, considerations 84
space reclamation
configuring 295
disabling 295
guest OS 297
VMware, Inc.
Index
manual 296
obtaining configuration 296
VMFS5 294
VMFS6 294
space reclamation priority, modify 296
SPBM 211
standard switches 88
static targets, removing 94
static discovery addresses 93
storage
access for virtual machines 24
adapters 20
introduction 13
local 14
networked 15
provisioning 287
rescan 121
supported vSphere features 24
types 14
used by virtual machines 289
storage adapter, rescan 121
storage adapters, viewing 20
storage devices
attaching 124
detaching 124
disconnections 122
displaying 195
displaying for a host 19, 118
displaying for an adapter 19, 119
erasing 128
hardware acceleration status 280
managing 117
marking as local flash 130
naming 119
paths 190
viewing 18, 117
storage filters
disabling 172
host rescan 173
RDM 173
same host and transports 173
VMFS 173
storage policies
cloning 227
editing 227
noncompliant 231
reapplying 232
rule sets 218
SPBM 211
virtual machines 227
storage providers
and VVols 241
certificates 237
VMware, Inc.
requirements 235
unregistering 236
updating 237
viewing 236
storage systems
performance 112
types 36, 66
Storage APIs, Storage Awareness 233
storage area network 63
Storage Array Type Plug-Ins 187
storage arrays, performance 60
storage capabilities 234
storage compliance
storage policy 229
virtual machine 230
storage device
connection status 127
renaming 120
storage devices, marking as local 131
storage policy
applying to a virtual machine 228
compliance 229
deleting 226
storage policy components
defining 221
deleting 222
editing 222
viewing 221
storage provider certificates 237
storage providers, registering 235
storage space 287
storage status 234
storage topology 234
storage virtualization 13
Storage vMotion, and I/O filters 275
STP 46
swap cache, configure with virtual flash
resource 133
swap to host cache 135
T
tags
applying to datastores 215
creating 215
tape devices 40
targets 17, 65
targets vs. LUNs 65
technical support 9
thick provisioning 287
thin disks, creating 289
thin provisioning 287
317
vSphere Storage
thin-provisioned LUNs
identify 292
reporting 292
third-party backup package 33
third-party management applications 32
TimeoutValue parameter 39, 70
troubleshooting
changing iSCSI boot parameters 109
loss of network connection 109
U
unbinding, VVols 243
unmap command
guest OS 297
VMFS 294
unplanned device loss 122, 125
updated information 11
uploading files 169
USB 14
use cases 28
V
VAAI claim rules
defining 282
deleting 283
VAAI filter 281
VAAI plug-in 281
VAAI filter, displaying 279
VAAI plug-ins, displaying 279
VAIO filters
classes 266
components 266
workflow 269
virtual disk, repair 307
virtual disks
extending 306
formats 288
supported formats 303
virtual flash
disabling 134
DRS support 138
HA support 138
Virtual Volumes
changing default policy 255
guidelines 260
performance 262
with replication 256
virtual disk files
copying 170
renaming 171
virtual flash resource
configure a swap cache 133
considerations 133
remove 134
setup 134
318
virtual flash resource, configuring host
cache 136
virtual machine I/O, queues 200
virtual machine storage policies, default 216
virtual machine storage policy, compliance 230
virtual machines
accessing FC SAN 37
accessing iSCSI SAN 68
assigning WWNs to 42
configuration files 127
configuration parameters 127
Flash Read Cache 138
I/O delay 184
locations 30
with RDMs 208
virtual ports (VPORTs) 41
Virtual SAN, default policies 216
Virtual SAN datastores, characteristics 21
virtual volumes
and virtual disks 240
assigning VM storage policy 254
snapshots 248
VM storage policies 253
Virtual Volumes datastore, changing default
policy 255
Virtual Volumes datastores
characteristics 21
default policies 216
mounting 168
unmounting 167
Virtual Volumes functionality
about
See VVols functionality
Virtual Volumes, best practices 260
Virtual Volumes, Network Time Protocol,
Network Time Protocol 249
VM Component Protection 127
VM storage polices, workflow 212
VM storage policies
and rules 219
and virtual volumes 244
creating 218
defining storage-specific rules 225
managing 218
reviewing compatible datastores 226
VM Storage Policies interface
and I/O filter characteristics 214
and storage capabilities 214
VM storage policy
assigning 228
defining common rules 224
starting creation 223
VMCA, and Virtual Volumes 247
VMFS
checking metadata consistency 177
VMware, Inc.
Index
comparing versions 142
conversion 302
locking 146
one volume per LUN 70
resignaturing 163
vmkfstools 299
VMFS datastores
adding extents 165
changing signatures 164
characteristics 21
creating 160
creating on Fibre Channel storage 160
creating on iSCSI storage 160
creating on SCSI disk 160
deleting 168
disk formats 144
increasing 165
increasing capacity 165
mounting 168
sharing 145
unmounting 167
VMFS datastore, configuring host cache 135
VMFS resignaturing 163
VMFS6 datastores, space reclamation 295
VMkernel interfaces 88
vmkfstools
breaking locks 308
cloning disks 305
creating RDMs 306, 307
creating virtual disks 303
deleting virtual disks 305
device options 308
disk chain 308
extending virtual disks 306
file system options 301
geometry 307
inflating thin disks 304
initializing virtual disks 304
overview 299
RDM attributes 307
removing zeroed blocks 304
renaming virtual disks 305
SCSI reservations 308
syntax 299
upgrading virtual disks 306
virtual disk options 303
virtual disks conversion 304
vmkfstools -C command 301
vmkfstools -G command 302
vmkfstools -P command 301
vmkfstools -v command 300
VMware, Inc.
vmkfstools -Z command 302
vmkfstools command options 300
vMotion 27, 28, 40, 70
VMware DRS, using with vMotion 70
VMware HA 27
VMware NMP
I/O flow 188
See also Native Multipathing Plug-In
VMware On-disk Metadata Analyzer, See VOMA
VMware PSPs, See Path Selection Plug-Ins
VMware SATPs, See Storage Array Type PlugIns
VOMA 177
VVol datastores
characteristics 21
creating VMs 252
mounting 168
unmounting 167
VVols
and VM storage policies 244
VM storage policies 253
VVols functionality
about 239
and storage protocols 244
architecture 246
binding 243
characteristics 260
concepts 240
datastores 243
limitations 260
prerequisites 248
protocol endpoints 242
storage containers 242
unbinding 243
workflow 249
See also Virtual Volumes
VVols functionality, concepts 240
VVols protocol endpoints, editing paths 252
VVols storage providers, registering 250
VVols VASA providers 241
W
Windows guest OS timeout 185
World Wide Names, See WWNs
World Wide Port Names, See WWPNs
WWNNs 42
WWNs
assigning to virtual machines 42
changing 43
WWPNs 36, 42
Z
zoning 35, 36
319
vSphere Storage
320
VMware, Inc.
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