EMC FC4700 Configuration Planning Manual

EMC Enterprise Storage

EMC Fibre Channel Storage System

Model FC4700

CONFIGURATION PLANNING GUIDE

P/N 014003016-A03

EMC Corporation

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EMC

2

, EMC, Navisphere, CLARiiON, MOSAIC:2000, and Symmetrix are registered trademarks and EMC Enterprise Storage, The Enterprise Storage

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ii EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide

Contents

Preface

..............................................................................................................................ix

Chapter 1 About Fibre Channel FC4700 Storage Systems and

Storage Networks

Introducing Fibre Channel Storage Systems.................................1-2

Fibre Channel Background..............................................................1-3

Fibre Channel Storage Components ..............................................1-4

Server Component (Host Bus Adapter Driver Package with

Software) .....................................................................................1-4

Interconnect Components ........................................................1-4

Storage Component (Storage Systems, SPs, and Other

Hardware)...................................................................................1-7

Types of Storage-System Installations ...........................................1-8

About Switched Shared Storage and SANs (Storage Area

Networks) ..........................................................................................1-9

Storage Groups.........................................................................1-10

Storage-System Hardware......................................................1-13

Chapter 2 RAID Types and Tradeoffs

Introducing RAID .............................................................................2-2

Disk Striping...............................................................................2-2

Mirroring.....................................................................................2-2

RAID Groups and LUNs ..........................................................2-3

RAID Types........................................................................................2-4

RAID 5 Group (Individual Access Array) .............................2-4

RAID 3 Group (Parallel Access Array)...................................2-5

RAID 1 Mirrored Pair................................................................2-7

RAID 0 Group (Nonresident Array) .......................................2-7

EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide iii

Contents

Chapter 3

Chapter 4

Chapter 5

RAID 1/0 Group (Mirrored RAID 0 Group) .........................2-8

Individual Disk Unit .................................................................2-9

Hot Spare ....................................................................................2-9

RAID Benefits and Tradeoffs.........................................................2-12

Performance .............................................................................2-13

Storage Flexibility ....................................................................2-14

Data Availability and Disk Space Usage..............................2-14

Guidelines for RAID Groups ........................................................2-17

Sample Applications for RAID Types..........................................2-19

About MirrorView Remote Mirroring Software

What Is EMC MirrorView Software? .............................................3-2

MirrorView Features and Benefits .................................................3-4

Provision for Disaster Recovery with Minimal Overhead ..3-4

Local High Availability ............................................................3-4

Cross Mirroring..........................................................................3-4

Integration with EMC SnapView LUN Copy Software.......3-5

How MirrorView Handles Failures ...............................................3-5

Primary Image Failure ..............................................................3-5

Secondary Image Failure..........................................................3-6

MirrorView Example........................................................................3-7

MirrorView Planning Worksheet....................................................3-9

About SnapView Snapshot Copy Software

What Is EMC SnapView Software? ................................................4-2

Snapshot Components ..............................................................4-3

Sample Snapshot Session.................................................................4-4

Snapshot Planning Worksheet ........................................................4-5

Planning File Systems and LUNs

Multiple Paths to LUNs ...................................................................5-2

Sample Shared Switched Installation ............................................5-3

Sample Unshared Direct Installation .............................................5-7

Planning Applications, LUNs, and Storage Groups....................5-8

Application and LUN Planning ..............................................5-8

Application and LUN Planning Worksheet ..........................5-9

LUN and Storage Group Planning Worksheet ...................5-10

LUN Details Worksheet..........................................................5-13

iv EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide

Contents

Chapter 6 Storage-System Hardware

Hardware for FC4700 Storage Systems......................................... 6-3

Storage Hardware — Rackmount DPE-Based Storage

Systems ....................................................................................... 6-3

Disks............................................................................................ 6-4

Storage Processor (SP) .............................................................. 6-5

Planning Your Hardware Components ........................................ 6-8

Components for Shared Switched Storage............................ 6-8

Components for Shared-or-Clustered Direct Storage ......... 6-8

Components for Unshared Direct Storage ............................ 6-8

Hardware Data Sheets ..................................................................... 6-9

DPE Data Sheet.......................................................................... 6-9

DAE Data Sheet....................................................................... 6-11

Cabinets for Rackmount Enclosures............................................ 6-12

Cable and Configuration Guidelines .......................................... 6-13

Hardware Planning Worksheets .................................................. 6-13

Cable Planning Template....................................................... 6-14

Sample Cable Templates........................................................ 6-16

Hardware Component Worksheet........................................ 6-17

Chapter 7 Storage-System Management

Introducing Navisphere Management Software ......................... 7-2

Using Navisphere Manager Software ........................................... 7-3

Storage Management Worksheet ................................................... 7-4

Index

................................................................................................................................ i-1

EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide v

Contents vi EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide

Figures

6-1

6-2

6-3

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6-5

6-6

4-1

4-2

5-1

5-2

2-6

2-7

3-1

3-2

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1-9

1-10

1-11

2-1

1-5

1-6

1-7

1-8

1-1

1-2

1-3

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Cutaway View of FC4700 Storage System ................................................ 1-2

Nodes - Initiator and Target ....................................................................... 1-3

Switch Topology (Port to Port) ................................................................... 1-5

A Switch Zone ............................................................................................... 1-6

16-Port Switch, Back View .......................................................................... 1-7

Model 4700 DPE ............................................................................................ 1-7

Types of Storage-System Installation ........................................................ 1-8

Components of a SAN ................................................................................. 1-9

Sample Shared Storage Configuration .................................................... 1-11

Data Access Control with Shared Storage .............................................. 1-12

Storage System with DPE and Three DAEs ........................................... 1-13

Multiple LUNs in a RAID Group ............................................................... 2-3

RAID 5 Group ............................................................................................... 2-5

RAID 3 Group ............................................................................................... 2-6

RAID 1 Mirrored Pair .................................................................................. 2-7

RAID 1/0 Group ........................................................................................... 2-9

How a Hot Spare Works ............................................................................ 2-11

Disk Space Usage in the RAID Configuration ....................................... 2-16

Sites with MirrorView Primary and Secondary Images ......................... 3-3

Sample MirrorView Configuration ............................................................ 3-7

SnapView Operations Model ...................................................................... 4-3

How a Snapshot Session Starts, Runs, and Stops .................................... 4-4

Sample Shared Switched Storage Configuration ..................................... 5-4

Unshared Direct Storage Example ............................................................. 5-7

Types of Storage-System Installation ........................................................ 6-2

DPE Storage-System Components — Rackmount Model ...................... 6-3

Rackmount Storage System with DPE and DAEs ................................... 6-4

Disk Modules and Module IDs .................................................................. 6-5

Shared Storage Systems ............................................................................... 6-6

Cable Planning Template — FC4700 Shared Storage System .............. 6-14

EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide vii

Figures

6-7

7-1

Sample Shared Storage Installation .......................................................... 6-16

Sample Shared Switched Environment with Manager ........................... 7-3

viii EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide

Preface

This planning guide provides an overview of Fibre Channel disk-array storage-system models and offers useful background information and worksheets to help you plan.

Please read this guide

• if you are considering purchase of an EMC FC-series (Fibre

Channel) FC4700 disk-array storage system and want to understand its features; or

• before you plan the installation of a storage system.

Audience for the Manual

You should be familiar with the host servers that will use the storage systems and with the operating systems of the servers. After reading this guide, you will be able to

• determine the best storage-system components for your installation

• determine your site requirements

• configure storage systems correctly

EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide ix

Preface

Organization of the Manual

Chapter 1

Chapter 2

Chapter 3

Chapter 4

Provides background information about Fibre Channel features and explains the major types of storage.

Describes the RAID Groups and the different ways they store data.

Describes the optional EMC MirrorView™ remote mirroring software.

Describes the optional EMC SnapView™ snapshot copy software.

Chapter 5

Chapter 6

Helps you plan your storage system software and LUNs.

Explains the hardware components of storage systems.

Chapter 7

Describes storage-system management utilities.

Conventions Used in This Manual

A note presents information that is important, but not hazard-related.

Where to Get Help Obtain technical support by calling your local sales office.

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Canada:

Worldwide:

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Your Comments and ask for Customer Service.

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x EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide

Invisible Body Tag

1

About Fibre Channel

FC4700 Storage

Systems and Storage

Networks

This chapter introduces Fibre Channel FC4700 disk-array storage systems and storage area networks (SANs). Major sections are

• Introducing Fibre Channel Storage Systems..................................1-2

• Fibre Channel Background ...............................................................1-3

• Fibre Channel Storage Components................................................1-4

• Types of Storage-System Installations.............................................1-8

• About Switched Shared Storage and SANs (Storage Area

Networks)............................................................................................1-9

About Fibre Channel FC4700 Storage Systems and Storage Networks 1-1

1

About Fibre Channel FC4700 Storage Systems and Storage Networks

Introducing Fibre Channel Storage Systems

EMC Fibre Channel FC4700 disk-array storage systems provide terabytes of disk storage capacity, high transfer rates, flexible configurations, and highly available data at low cost.

EMC1801

Figure 1-1 Cutaway View of FC4700 Storage System

A storage-system package includes a host bus adapter driver kit with hardware and software to connect with a server, storage management software, Fibre Channel interconnect hardware, and one or more storage systems.

1-2 EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide


1

Fibre Channel Background

Fibre Channel is a high-performance serial protocol that allows transmission of both network and I/O channel data. It is a low level protocol, independent of data types, and supports such formats as

SCSI and IP.

The Fibre Channel standard supports several physical topologies, including switched fabric point-to-point and arbitrated loop (FC-AL).

The topologies used by the Fibre Channel storage systems described in this manual are switched fabric and FC-AL.

A switch fabric is a set of point-to-point connections between nodes, the connection being made through one or more Fibre Channel switches. Each node may have its own unique address, but the path between nodes is governed by a switch. The nodes are connected by optical cable.

A Fibre Channel arbitrated loop is a circuit consisting of nodes. Each node has a unique address, called a Fibre Channel arbitrated loop address. The nodes are connected by optical cables. An optical cable can transmit data over great distances for connections that span entire enterprises and can support remote disaster recovery systems.

Each connected device in a switched fabric or arbitrated loop is a server adapter (initiator) or a target (storage system). The switches are not considered nodes.

Server Adapter (initiator)

Node

Connection

Storage System (target)

Node

EMC1802

Figure 1-2 Nodes - Initiator and Target

Fibre Channel Background 1-3

1


Fibre Channel Storage Components

A Fibre Channel storage system has three main components:

• Server component (host bus adapter driver package with adapter and software)

• Interconnect components (cables based on Fibre Channel standards, and switches)

• Storage component (storage system with storage processors —

SPs — and power supply and cooling hardware)

Server Component (Host Bus Adapter Driver Package with Software)

The host bus adapter driver package includes a host bus adapter and support software. The adapter is a printed-circuit board that slides into an I/O slot in the server’s cabinet. It transfers data between server memory and one or more disk-array storage systems over

Fibre Channel — as controlled by the support software (adapter driver).

One or more servers can use a storage system. For high availability — in event of an adapter failure — a server can have two adapters.

Server

EMC1803

Depending on your server type, you may have a choice of adapters.

The adapter is designed for a specific kind of bus; for example, a PCI bus or SBUS. Any adapter you choose must support optical cable.

1-4

Interconnect Components

The interconnect components include the optical cables between components and any Fibre Channel switches.

The maximum length of optical cable between server and switch or storage system is 500 meters (1,640 feet) for 62.5-micron multimode cable or 10 kilometers (6.2 miles) for 9-micron single-mode cable.

EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide


1

With extenders, optical cable can span up to 40 kilometers (25 miles) or more. This ability to span great distances is a major advantage of optical cable.

Details on cable lengths and rules appear later in this manual.

Fibre Channel Switches

A Fibre Channel switch, which is required for switched shared storage (a storage area network, SAN), connects all the nodes cabled to it using a fabric topology. A switch adds serviceability and scalability to any installation; it allows on-line insertion and removal of any device on the fabric and maintains integrity if any connected device stops participating. A switch also provides server-to-storage-system access control. A switch provides point-to-point connections

You can cascade switches (connect one switch port to another switch) for additional port connections.

Server Server Server

Figure 1-3

SP SP SP SP

Storage system Storage system

EMC1805

To illustrate the point-to-point quality of a switch, this figure shows just one adapter per server and one switch. Normally, such installations include two adapters per server and two switches.

Switch Topology (Port to Port)

Fibre Channel Storage Components 1-5

1


Switch Zoning

Switch zoning lets an administrator define paths between connected nodes based on the node’s unique World Wide Name. Each zone encloses one or more server adapters and one or more SPs. A switch can have as many zones as it has ports.

The current connection limits are four SP ports to one adapter port

(the SPs fan in to the adapter) and 15 adapters to one SP (the SPs fan out to the adapters). There are several zone types, including the single-initiator type, which is the recommended type for

FC4700-series systems.

In the following figure, Server 1 has access to one SP (SP A) in storage systems 1 and 2; it has no access to any other SP.

Server 1 Server 2 Server 3

Zone

Switch fabric

SP SP

Storage system 1

SP SP

Storage system 2

SP SP

Storage system 3

To illustrate switch zoning, this figure shows just one HBA per server and one switch. Normally, such installations will include two HBAs per server and two switches.

EMC1806

Figure 1-4 A Switch Zone

If you do not define a zone in a switch, all adapter ports connected to the switch can communicate with all SP ports connected to the switch. However, access to an SP does not necessarily provide access to the SP’s storage; access to storage is governed by the Storage

Groups you create (defined later).

Fibre Channel switches are available with 16 or 8 ports. They are compact units that fit in 2 U (3.5 inches) for the 16 port or 1 U (1.75



1 inches) for the 8 port. They are available to fit into a rackmount cabinet or as small deskside enclosures.

Ports

EMC1807

Figure 1-5 16-Port Switch, Back View

If your servers and storage systems will be far apart, you can place the switches closer to the servers or the storage systems, as convenient.

A switch is technically a repeater, not a node, in a Fibre Channel loop.

However, it is bound by the same cabling distance rules as a node.

Storage Component (Storage Systems, SPs, and Other Hardware)

EMC FC-series disk-array storage systems, with their storage processors, power supplies, and cooling hardware form the storage component of a Fibre Channel system. The controlling unit, a Model

FC4700 disk-array processor enclosure (DPE) looks like the following figure.

Disk modules

EMC1808

Figure 1-6 Model 4700 DPE

DPE hardware details appear in a later chapter.

Fibre Channel Storage Components 1-7

1


Types of Storage-System Installations

You can use a storage system in any of several types of installation:

• Unshared direct with one server is the simplest and least costly.

• Shared-or-clustered direct , with a limit of two servers, lets two servers share storage resources with high availability.

• Shared switched , with two switch fabrics, lets two to 15 servers share the resources of several storage systems in a storage area network (SAN). Shared switched installations are available in high-availability versions (two HBAs per server) or with one

HBA per server. Shared switched storage systems can have multiple paths to each SP, providing multipath I/O for dynamic load sharing and greater throughput.

Unshared Direct

(one or two servers)

Server

Shared or Clustered

Direct (two servers)

Server Server

Shared Switched (multiple servers,

Multiple Paths to SPs)


1-8

SP A SP B

Storage system

Path 1

Path 2

SP A SP B

Storage system

Switch fabric Switch fabric

SP A SP B

Storage system

SP A SP B

Storage system

SP A SP B

Storage system

EMC1809

Figure 1-7 Types of Storage-System Installation

Storage systems for any shared installation require EMC Access

Logix TM software to control server access to the storage-system LUNs.

The Shared-or-clustered direct installation can be either shared (that is, use Access Logix to control LUN access) or clustered (without

Access Logix, but with operating system cluster software controlling

LUN access), depending on the hardware model. FC4700 storage systems are shared; they include Access Logix, which means the servers need not use cluster software to control LUN access.



1

About Switched Shared Storage and SANs (Storage Area

Networks)

This section explains the features that let multiple servers share disk-array storage systems on a SAN (storage area network).

A SAN is one or more storage devices connected to servers through

Fibre Channel switches to provide a central location for disk storage.

Centralizing disk storage among multiple servers has many advantages, including

• highly available data

• flexible association between servers and storage capacity

• centralized management for fast, effective response to users’ data storage needs

• easier file backup and recovery

An EMC SAN is based on shared storage; that is, the SAN requires

EMC Access Logix to provide flexible access control to storage-system LUNs. Within the SAN, a network connection to each

SP in the storage system lets you configure and manage it.



Path 1

Path 2

SP A SP B

Storage system

SP A SP B

Storage system

EMC1810

Figure 1-8 Components of a SAN

Fibre Channel switches can control data access to storage systems through the use of switch zoning. With zoning, an administrator can specify groups (called zones) of Fibre Channel devices (such as

About Switched Shared Storage and SANs (Storage Area Networks) 1-9

1


Storage Groups

host-bus adapters, specified by worldwide name), and SPs between which the switch fabric will allow communication.

However, switch zoning cannot selectively control data access to

LUNs in a storage system, because each SP appears as a single Fibre

Channel device to the switch fabric. So switch zoning can prevent or allow communication with an SP, but not with specific disks or LUNs attached to an SP. For access control with LUNs, a different solution is required: Storage Groups.

A Storage Group is one or more LUNs (logical units) within a storage system that is reserved for one or more servers and is inaccessible to other servers. Storage Groups are the central component of shared storage; storage systems that are unshared do not use Storage

Groups.

When you configure shared storage, you specify servers and the

Storage Group(s) each server can read from and/or write to. The Base

Software running in each storage system enforces the server-to-Storage Group permissions.

A Storage Group can be accessed by more than one server if all the servers run cluster software. The cluster software enforces orderly access to the shared Storage Group LUNs.

The following figure shows a simple shared storage configuration consisting of one storage system with two Storage Groups. One

Storage Group serves a cluster of two servers running the same operating system, and the other Storage Group serves a UNIX® database server. Each server is configured with two independent paths to its data, including separate host bus adapters, switches, and

SPs, so there is no single point of failure for access to its data.



1

Highly available cluster

File server

Operating system A

Mail server

Operating system A

Database server

Operating system B


Path 1

Path 2

Cluster Storage

Group

Database Server

Storage Group

SP A SP B

LUN

LUN

LUN

LUN

LUN

LUN

LUN

Physical storage system with up to

100 disks per system

EMC1811

Figure 1-9 Sample Shared Storage Configuration

Access Control with Shared Storage

Access control permits or restricts a server’s access to shared storage.

Configuration access, the ability to configure storage systems, is governed by username and password access to a configuration file on each server.

Data access, the ability to read and write information to storage-system LUNs, is provided by Storage Groups. During storage-system configuration, using a management utility, the system administrator associates a server with one or more LUNs. The associated LUNs compose a Storage Group.


1


Each server sees its Storage Group as if it were an entire storage system, and never sees the other LUNs on the storage system.

Therefore, it cannot access or modify data on LUNs that are not part of its Storage Group. However, you can define a Storage Group to be

accessible by more than one server, if, as shown above in Figure 1-9,

the servers run cluster software.

The following figure shows access control through Storage Groups.

Each server has exclusive read and write access to its designated

Storage Group.

Admin Server Inventory Server

Operating system A

Operating system A


E-mail Server Web Server

Operating system B

Operating system B


Admin Storage Group

Dedicated Data access by adapters 00, 01

Inventory Storage Group

Dedicated Data access by adapters 02, 03

E-mail and Web Server

Storage Sroup Shared

Data access by adapters 04, 05, 06, 07

SP A SP B

LUN

LUN

LUN

LUN

LUN

LUN

LUN

LUN

LUN

LUN

Path 1

Path 2

EMC1812

Figure 1-10 Data Access Control with Shared Storage



1

Storage-System Hardware

A Fibre Channel storage system is based on a disk-array processor enclosure (DPE).

A DPE is a 10-slot enclosure with hardware RAID features provided by one or two storage processors (SPs). For high availability, two SPs are required. In addition to its own disks, each DPE can support up to nine 10-slot Disk Array Enclosures (DAEs) for a total of 100 disks per storage system.

DAE

DAE

DAE

DPE

Standby power supply (SPS)

EMC1741

Figure 1-11 Storage System with DPE and Three DAEs

What Next?

For information about RAID types and RAID tradeoffs, continue to the next chapter.

For information on the MirrorView™ or SnapView™ software

options, go to Chapter 3 or 4.

To plan LUNs and file systems, skip to Chapter 5. For details on the

storage-system hardware, skip to Chapter 6.


1



Invisible Body Tag

2

RAID Types and

Tradeoffs

This chapter explains RAID types you can choose for your storage- system LUNs. If you already know about RAID types and know which ones you want, you can skip this background information and

go to the planning chapter (Chapter 5). Topics are

• Introducing RAID ..............................................................................2-2

• RAID Types .........................................................................................2-4

• RAID Benefits and Tradeoffs ..........................................................2-12

• Guidelines for RAID Groups..........................................................2-17

• Sample Applications for RAID Types ...........................................2-19

RAID Types and Tradeoffs 2-1

2

RAID Types and Tradeoffs

Introducing RAID

Disk Striping

Mirroring

The storage system uses RAID (redundant array of independent disks) technology. RAID technology groups separate disks into one logical unit (LUN) to improve reliability and/or performance.

The storage system supports five RAID levels and two other disk configurations, the individual unit and the hot spare (global spare).

You group the disks into one RAID Group by binding them using a storage-system management utility.

Four of the RAID Groups use disk striping and two use mirroring.

Using disk stripes, the storage-system hardware can read from and write to multiple disks simultaneously and independently. By allowing several read/write heads to work on the same task at once, disk striping can enhance performance. The amount of information read from or written to each disk makes up the stripe element size.

The stripe size is the stripe element size multiplied by the number of disks in a group. For example, assume a stripe element size of 128 sectors (the default) and a five-disk group. The group has five disks, so you would multiply five by the stripe element size of 128 to yield a stripe size of 640 sectors.

The storage system uses disk striping with most RAID types.

Mirroring maintains a copy of a logical disk image that provides continuous access if the original image becomes inaccessible. The system and user applications continue running on the good image without interruption. There are two kinds of mirroring: hardware mirroring, in which the SP synchronizes the disk images; and software mirroring, in which the operating system synchronizes the images. Software mirroring consumes server resources, since the operating system must mirror the images, and has no offsetting advantages; we mention it here only for historical completeness.

With a storage system, you can create a hardware mirror by binding disks as a RAID 1 mirrored pair or a RAID 1/0 Group (a mirrored

RAID 0 Group); the hardware will then mirror the disks automatically.

With a LUN of any RAID type, a storage system can maintain a remote copy using the optional MirrorView software. MirrorView



2 remote mirroring, primarily useful for disaster recovery, is explained

in Chapter 3.

RAID Groups and LUNs

Some RAID types let you create multiple LUNs on one RAID Group.

You can then allot each LUN to a different user, server, or application.

For example, a five-disk RAID 5 Group that uses 36-Gbyte disks offers 144 Gbytes of space. You could bind three LUNs, say with 24,

60, and 60 Gbytes of storage capacity, for temporary, mail, and customer files.

One disadvantage of multiple LUNs on a RAID Group is that I/O to each LUN may affect I/O to the others in the group; that is, if traffic to one LUN is very heavy, I/O performance with other LUNs may degrade. The main advantage of multiple LUNs per RAID Group is the ability to divide the enormous amount of disk space provided by

RAID Groups on newer, high-capacity disks.

LUN 0 temp

LUN 1 mail

LUN 2 customers

Disk

LUN 0 temp

LUN 1 mail

LUN 2 customers

Disk

RAID Group

LUN 0 temp

LUN 1 mail

LUN 2 customers

Disk

LUN 0 temp

LUN 1 mail

LUN 2 customers

Disk

LUN 0 temp

LUN 1 mail

LUN 2 customers

Disk

EMC1814

Figure 2-1 Multiple LUNs in a RAID Group

Introducing RAID 2-3

2


RAID Types

You can choose from the following RAID types: RAID 5, RAID 3,

RAID 1, RAID 0, RAID 1/0, individual disk unit, and hot spare.

You can choose an additional type of redundant disk — a remote mirror — for any RAID type except a hot spare.

RAID 5 Group (Individual Access Array)

A RAID 5 Group usually consists of five disks (but can have three to sixteen). A RAID 5 Group uses disk striping. With a RAID 5 group, you can create up to 32 RAID 5 LUNs to apportion disk space to different users, servers, and applications.

The storage system writes parity information that lets the Group continue operating if a disk fails. When you replace the failed disk, the SP rebuilds the group using the information stored on the working disks. Performance is degraded while the SP rebuilds the group. However, the storage system continues to function and gives users access to all data, including data stored on the failed disk.

The following figure shows user and parity data with the default stripe element size of 128 sectors (65,536 bytes) in a five-disk RAID 5 group. The stripe size comprises all stripe elements. Notice that the disk block addresses in the stripe proceed sequentially from the first disk to the second, third, and fourth, then back to the first, and so on.



2

Stripe element size

Stripe

Blocks

0-127

First disk

512-639 1024-11511536-1663 Parity

…

Second disk

128-255 640-767 1152-1279 Parity 2048-2175

…

256-383 768-895

Third disk

Parity 1664-1791 2176-2303

…

Stripe size

384-511

Parity

Fourth disk

1280-1407 1792-1919 2304-2431

…

User data

Parity data

Parity

Fifth disk

896-1023 1408-1535 1920-2047 2432-2559

…

EMC1815

Figure 2-2 RAID 5 Group

RAID 5 Groups offer excellent read performance and good write performance. Write performance benefits greatly from storage-system caching.

RAID 3 Group (Parallel Access Array)

A RAID 3 Group consists of five or more disks. The hardware always reads from or writes to all the disks. A RAID 3 Group uses disk striping. To maintain the RAID 3 performance, you can create only one LUN per RAID 3 group.

The storage system writes parity information that lets the Group continue operating if a disk fails. When you replace the failed disk, the SP rebuilds the group using the information stored on the working disks. Performance is degraded while the SP rebuilds the group. However, the storage system continues to function and gives users access to all data, including data stored on the failed disk.

The following figure shows user and parity data with a data block size of 2 Kbytes in a RAID 3 Group. Notice that the byte addresses

RAID Types 2-5

2

RAID Types and Tradeoffs proceed from the first disk to the second, third, and fourth, then the first, and so on.

Stripe size

Stripe element size

Data block

Bytes

0-511

First disk

2048-2559 4096-4607 6144-6655 8192-8603

…

Second disk

512-1023 2560-3071 4608-5119 6656-7167 8604-9115

…

Third disk

1024-1535 3072-3583 5120-5631 7168-7679 9116-9627

…

1536-2047

Fourth disk

3584-4095 5632-6143 7680-8191 9628-10139

…

Parity Parity

Fifth disk

Parity Parity Parity

…

User data

Parity data

EMC1816

Figure 2-3 RAID 3 Group

RAID 3 differs from RAID 5 in several important ways. First, in a

RAID 3 Group the hardware processes disk requests serially; whereas in a RAID 5 Group the hardware can interleave disk requests. Second, with a RAID 3 Group, the parity information is stored on one disk; with a RAID 5 Group, it is stored on all disks. Finally, with a RAID 3

Group, the I/O occurs in small units (one sector) to each disk. A

RAID 3 Group works well for single-task applications that use I/Os of blocks larger than 64 Kbytes.

Each RAID 3 Group requires some dedicated SP memory (6 Mbytes recommended per group). This memory is allocated when you create the group, and becomes unavailable for storage-system caching. For top performance, we suggest that you do not use RAID 3 Groups with RAID 5, RAID 1/0, or RAID 0 Groups, since SP processing power and memory are best devoted to the RAID 3 Groups. RAID 1 mirrored pairs and individual units require less SP processing power, and therefore work well with RAID 3 Groups.



2

RAID 1 Mirrored Pair

A RAID 1 Group consists of two disks that are mirrored automatically by the storage-system hardware.

RAID 1 hardware mirroring within the storage system is not the same as software mirroring, remote mirroring, or hardware mirroring for other kinds of disks. Functionally, the difference is that you cannot manually stop mirroring on a RAID 1 mirrored pair, and then access one of the images independently. If you want to use one of the disks in such a mirror separately, you must unbind the mirror (losing all data on it), rebind the disk as the type you want, and software format the newly bound LUN.

With a storage system, RAID 1 hardware mirroring has the following advantages:

• automatic operation (you do not have to issue commands to initiate it)

• physical duplication of images

• a rebuild period that you can select during which the SP recreates the second image after a failure

With a RAID 1 mirrored pair, the storage system writes the same data to both disks, as follows.

0 1

First disk

2 3 4

…

User data

0 1

Second disk

2 3 4

…

EMC1817

Figure 2-4 RAID 1 Mirrored Pair

RAID 0 Group (Nonresident Array)

A RAID 0 Group consists of three to a maximum of sixteen disks. A

RAID 0 Group uses disk striping, in which the hardware writes to or reads from multiple disks simultaneously. You can create up to 32

LUNs per RAID 0 Group.

Unlike the other RAID levels, with RAID 0 the hardware does not maintain parity information on any disk; this type of group has no

RAID Types 2-7

2

RAID Types and Tradeoffs inherent data redundancy. RAID 0 offers enhanced performance through simultaneous I/O to different disks.

If the operating system supports software mirroring, you can use software mirroring with the RAID 0 Group to provide high availability. A desirable alternative to RAID 0 is RAID 1/0.

RAID 1/0 Group (Mirrored RAID 0 Group)

A RAID 1/0 Group consists of four, six, eight, ten, twelve, fourteen, or sixteen disks. These disks make up two mirror images, with each image including two to eight disks. The hardware automatically mirrors the disks. A RAID 1/0 Group uses disk striping. It combines the speed advantage of RAID 0 with the redundancy advantage of mirroring. With a RAID 1/0 Group, you can create up to 32 RAID 1/0

LUNs to apportion disk space to different users, servers, and applications.

The following figure shows the distribution of user data with the default stripe element size of 128 sectors (65,536 bytes) in a six-disk

RAID 1/0 Group. Notice that the disk block addresses in the stripe proceed sequentially from the first mirrored disks (first and fourth disks) to the second mirrored disks (second and fifth disks), to the third mirrored disks (third and sixth disks), and then from the first mirrored disks, and so on.



2

Stripe size

Stripe element size

Stripe

Blocks

0-127

First disk of primary image

384-511 768-895 1152-1279 1536-1663

…

128-255

Second disk of primary image

512-639 896-1023 1280-1407 1664-1791

…

256-383

Third disk of primary image

640-767 1024-1151 1408-1535 1792-1919

…

0-127

First disk of secondary image

384-511 768-895 1152-1279 1536-1663

…

128-255

Second disk of secondary image

512-639 896-1023 1280-1407 1664-1791

…

256-383

Third disk of secondary image

640-767 1024-1151 1408-1535 1792-1919

…

User data

EMC1818

Figure 2-5 RAID 1/0 Group

A RAID 1/0 Group can survive the failure of multiple disks, providing that one disk in each image pair survives.

Individual Disk Unit

An individual disk unit is a disk bound to be independent of any other disk in the cabinet. An individual unit has no inherent high availability, but you can make it highly available by using software mirroring with another individual unit. You can create one LUN per individual disk unit. If you want to apportion the disk space, you can do so using partitions, file systems, or user directories.

Hot Spare

A hot spare is a dedicated replacement disk on which users cannot store information. A hot spare is global: if any disk in a RAID 5

Group, RAID 3 Group, RAID 1 mirrored pair, or RAID 1/0 Group fails, the SP automatically rebuilds the failed disk’s structure on the hot spare. When the SP finishes rebuilding, the disk group functions

RAID Types 2-9

2

RAID Types and Tradeoffs as usual, using the hot spare instead of the failed disk. When you replace the failed disk, the SP copies the data from the former hot spare onto the replacement disk.

When the copy is done, the disk group consists of disks in the original slots, and the SP automatically frees the hot spare to serve as a hot spare again. A hot spare is most useful when you need the highest data availability. It eliminates the time and effort needed for someone to notice that a disk has failed, find a suitable replacement disk, and insert the disk.

When you plan to use a hot spare, make sure the disk has the capacity to serve in any RAID Group in the storage-system chassis. A RAID Group cannot use a hot spare that is smaller than a failed disk in the group.

You can have one or more hot spares per storage-system chassis. You can make any disk in the chassis a hot spare, except for one of the disks that stores Base Software or the write cache vault. That is, a hot spare can be any of the following disks:

DPE system without write caching:

DPE system with write caching: disk IDs 003-199 disk IDs 009-199

An example of hot spare usage for a deskside DPE storage system follows.



2

0 1 2 3 4 5 6 7 8

9

Hot spare

1.

RAID 5 Group consists of disk modules 0-4; RAID 1 mirrored pair is modules 5 and 6; hot spare is module 9.

2.

Disk module 3 fails.

3.

RAID 5 Group becomes modules 0, 1, 2, 9, and 4; now no hot spare is available.

4.

System operator replaces failed module 3 with a functional module.

5.

Once again, RAID 5 Group consists of modules 0-4 and hot spare is 9.

EMC1819

Figure 2-6 How a Hot Spare Works

RAID Types 2-11

2


RAID Benefits and Tradeoffs

This section reviews RAID types and explains their benefits and tradeoffs. You can create seven types of LUN:

• RAID 5 Group (individual access array)

• RAID 3 Group (parallel access array)

• RAID 1 mirrored pair

• RAID 1/0 Group (mirrored RAID 0 Group); a RAID 0 Group mirrored by the storage-system hardware

• RAID 0 Group (nonredundant individual access array); no inherent high-availability features

• Individual unit; no inherent high-availability features

• Hot spare; serves only as an automatic replacement for any disk in a RAID type other than 0; does not store data during normal system operations

Plan the disk unit configurations carefully. After a disk has been bound into a

LUN, you cannot change the RAID type of that LUN without unbinding it, and this means losing all data on it.

The following table compares the read and write performance, tolerance for disk failure, and relative cost per megabyte (Mbyte) of the RAID types. Figures shown are theoretical maximums.


Performance


2

Table 2-1 Performance, Availability, and Cost of RAID Types (Individual Unit = 1.0)

Disk configuration

RAID 5 Group with fivedisks

Relative read performance without cache

Relative write performance without cache

Relative cost per

Mbyte

Up to 5 with five disks

(for small I/O requests, 2 to 8 Kbytes)

Up to 1.25 with five disks

(for small I/O requests, 2 to

8 Kbytes)

1.25

RAID 3 Group with fivedisks

Up to 4 (for large I/O requests)

RAID 1 mirrored pair Up to 2

Up to 4 (for large I/O requests)

Up to 1

1.25

2

RAID 1/0 Group with

10 disks

Individual unit

Up to 10 Up to 5

1 1 1

Notes: These performance numbers are not based on storage-system caching. With caching, the performance numbers for RAID 5 writes improve significantly.

Performance multipliers vary with load on server and storage system.

RAID 5, with individual access, provides high read throughput by a allowing simultaneous reads from each disk in the group. RAID 5 write performance is excellent when the storage system uses write caching.

RAID 3, with parallel access, provides high throughput for sequential, large block-size requests (blocks of more than 64 Kbytes).

With RAID 3, the system accesses all five disks in each request but need not read data and parity before writing – advantageous for large requests but not for small ones. RAID 3 employs SP memory without caching, which means you do not need the second SP and BBU that caching requires.

Generally, the performance of a RAID 3 Group increases as the size of the I/O request increases. Read performance increases rapidly with read requests up to 1Mbyte. Write performance increases greatly for sequential write requests that are greater than 256 Kbytes. For applications issuing very large I/O requests, a RAID 3 LUN provides significantly better write performance than a RAID 5 LUN.

We do not recommend using RAID 3 in the same storage-system chassis with RAID 5 or RAID 1/0.

RAID Benefits and Tradeoffs 2-13

2


Storage Flexibility

A RAID 1 mirrored pair has its disks locked in synchronization, but the SP can read data from the disk whose read/write heads are closer to it. Therefore, RAID 1 read performance can be twice that of an individual disk while write performance remains the same as that of an individual disk.

A RAID 0 Group (nonredundant individual access array) or RAID

1/0 Group (mirrored RAID 0 Group) can have as many I/O operations occurring simultaneously as there are disks in the group.

Since RAID 1/0 locks pairs of RAID 0 disks the same way as RAID 1 does, the performance of RAID 1/0 equals the number of disk pairs times the RAID 1 performance number. If you want high throughput for a specific LUN, use a RAID 1/0 or RAID 0 Group. A RAID 1/0

Group requires at least four disks; a RAID 0 Group, at least three disks.

An individual unit needs only one I/O operation per read or write operation.

RAID types 5, 1, 1/0, and 0 allow multiple LUNs per RAID Group. If you create multiple LUNs on a RAID Group, the LUNs share the

RAID Group disks, and the I/O demands of each LUN affect the I/O service time to the other LUNs. For best performance, you may want to use one LUN per RAID Group.

Certain RAID Group types — RAID 5, RAID 1, RAID 1/0, and RAID

0 — let you create up to 32 LUNs in each group. This adds flexibility, particularly with large disks, since it lets you apportion LUNs of various sizes to different servers, applications, and users. Conversely, with RAID 3, there can be only one LUN per RAID Group, and the group must include five or nine disks — a sizable block of storage to devote to one server, application, or user. However, the nature of

RAID 3 makes it ideal for that single-threaded type of application.

Data Availability and Disk Space Usage

If data availability is critical and you cannot afford to wait hours to replace a disk, rebind it, make it accessible to the operating system, and load its information from backup, then use a redundant RAID

Group: RAID 5, RAID 3, RAID 1 mirrored pair, or RAID 1/0. If data availability is not critical, or disk space usage is critical, bind an individual unit.



2

A RAID 1 mirrored pair or RAID 1/0 Group provides very high data availability. They are more expensive than RAID 5 or RAID 3 Groups, since only 50 percent of the total disk capacity is available for user

data, as shown on page 2-13.

A RAID 5 or RAID 3 Group provides high data availability, but requires more disks than a mirrored pair. In a RAID 5 or RAID 3

Group of five disks, 80 percent of the disk space is available for user data. So RAID 5 and RAID 3 Groups use disk space much more efficiently than a mirrored pair. A RAID 5 or RAID 3 Group is usually more suitable than a RAID 1 mirrored pair for applications where high data availability, good performance, and efficient disk space usage are all of relatively equal importance.

For a LUN in any RAID Group, to provide for disaster recovery, you can establish a remote mirror at a distant site.

RAID Benefits and Tradeoffs 2-15

2


2-16

RAID 5 Group

1st disk user and parity data

2nd disk user and parity data

3rd disk user and parity data

4th disk user and parity data

5th disk user and parity data

RAID 3 Group

1st disk user data

2nd disk user data

3rd disk user data

4th disk user data

5th disk parity data

Disk Mirror (RAID 1 mirrored pair)

1st disk user data

2nd disk user data

50% user data

50% redundant data

100% user data

80% user data

20% parity data

RAID 0 Group

(nonredundant array)

1st disk user data

2nd disk user data

3rd disk user data

Hot Spare

Reserved

50% user data

50% redundant data

RAID 1/0 Group

1st disk user data

2nd disk user data

3rd disk user data

4th disk user data

5th disk user data

6th disk user data

Individual Disk Unit

User data 100% user data No user data

EMC1820

Figure 2-7 Disk Space Usage in the RAID Configuration

A RAID 0 Group (nonredundant individual access array) provides all its disk space for user files, but does not provide any high availability features. For high availability, you can use a RAID 1/0 Group instead.

A RAID 1/0 Group provides the best combination of performance and availability, at the highest cost per Mbyte of disk space.

An individual unit, like a RAID 0 Group, provides no high-availability features. All its disk space is available for user data, as shown in the figure above.



2

Guidelines for RAID Groups

To decide when to use a RAID 5 Group, RAID 3 Group, mirror (that is, a RAID 1 mirrored pair or RAID 1/0 Group, a RAID 0 Group, individual disk unit, or hot spare), you need to weigh these factors:

• Importance of data availability

• Importance of performance

• Amount of data stored

• Cost of disk space

The following guidelines will help you decide on RAID types.

Use a RAID 5 Group (individual access array) for applications where

• Data availability is very important.

• Large volumes of data will be stored.

• Multitask applications use I/O transfers of different sizes.

• Excellent read and good write performance is needed (write performance is very good with write caching).

• You want the flexibility of multiple LUNs per RAID Group.

Use a RAID 3 Group (parallel access array) for applications where


• Large volumes of data will be stored.

• A single-task application uses large I/O transfers (more than 64

Kbytes). The operating system must allow transfers aligned to start at disk addresses that are multiples of 2 Kbytes from the start of the LUN.

Use a RAID 1 mirrored pair for applications where


• Speed of write access is important and write activity is heavy.

Use a RAID 1/0 Group (mirrored nonredundant array) for applications where

• Data availability is critically important.

• Overall performance is very important.

Guidelines for RAID Groups 2-17

2


Use a RAID 0 Group (nonredundant individual access array) for applications where

• High availability is not important.

• You can afford to lose access to all data stored on a LUN if a single disk fails.

• Overall performance is very important.

Use an individual unit for applications where

• High availability is not important.

• Speed of write access is somewhat important.

Use a hot spare where

• In any RAID 5, RAID 3, RAID 1/0 or RAID 1 Group, high availability is so important that you want to regain data redundancy quickly without human intervention if any disk in the group fails.

• Minimizing the degraded performance caused by disk failure in a

RAID 5 or RAID 3 Group is important.



2

Sample Applications for RAID Types

This section describes some types of applications in which you would want to use a RAID 5 Group, RAID 3 Group, RAID 1 mirrored pair,

RAID 0 Group (nonredundant array), RAID 1/0 Group, or individual unit.

RAID 5 Group (individual access array) — Useful as a database repository or a database server that uses a normal or low percentage of write operations (writes are 33 percent or less of all I/O operations). Use a RAID 5 Group where multitask applications perform I/O transfers of different sizes. Write caching can significantly enhance the write performance of a RAID 5 Group.

For example, a RAID 5 Group is suitable for multitasking applications that require a large history database with a high read rate, such as a database of legal cases, medical records, or census information. A RAID 5 Group also works well with transaction processing applications, such as an airline reservations system, where users typically read the information about several available flights before making a reservation, which requires a write operation. You could also use a RAID 5 Group in a retail environment, such as a supermarket, to hold the price information accessed by the point-of-sale terminals. Even though the price information may be updated daily, requiring many write operations, it is read many more times during the day.

RAID 3 Group — A RAID 3 Group (parallel access array) works well with a single-task application that uses large I/O transfers (more than

64 Kbytes), aligned to start at a disk address that is a multiple of 2

Kbytes from the beginning of the logical disk. RAID 3 Groups can use

SP memory to great advantage without the second SP and battery backup unit required for storage-system caching.

You might use a RAID 3 Group for a single-task application that does large I/O transfers, like a weather tracking system, geologic charting application, medical imaging system, or video storage application.

RAID 1 mirrored pair — A RAID 1 mirrored pair is useful for logging or record-keeping applications because it requires fewer disks than a RAID 0 Group (nonredundant array) and provides high availability and fast write access. Or you could use it to store daily updates to a database that resides on a RAID 5 Group, and then, during off-peak hours, copy the updates to the database on the

RAID 5 Group.

Sample Applications for RAID Types 2-19

2


What Next?

RAID 0 Group (nonredundant individual access array) — Use a

RAID 0 Group where the best overall performance is important. In terms of high availability, a RAID 0 Group is less available than an individual unit. A RAID 0 Group (like a RAID 5 Group) requires a minimum of three disks. A RAID 0 Group is useful for applications using short-term data to which you need quick access.

RAID 1/0 Group (mirrored RAID 0 Group) — A RAID 1/0 Group provides the best balance of performance and availability. You can use it very effectively for any of the RAID 5 applications. A RAID 1/0

Group requires a minimum of four disks.

Individual unit — An individual unit is useful for print spooling, user file exchange areas, or other such applications, where high availability is not important or where the information stored is easily restorable from backup.

The performance of an individual unit is slightly less than a standard disk not in an storage system. The slight degradation results from SP overhead.

Hot spare — A hot spare provides no data storage but enhances the availability of each RAID 5, RAID 3, RAID 1, and RAID 1/0 Group in a storage system. Use a hot spare where you must regain high availability quickly without human intervention if any disk in such a

RAID Group fails. A hot spare also minimizes the period of degraded performance after a RAID 5 or RAID 3 disk fails.

This chapter explained RAID Group types and tradeoffs. To plan

LUNs and file systems, skip to Chapter 5. For details on the

storage-system hardware, skip to Chapter 6.

For storage-system management utilities, skip to Chapter 7.


Invisible Body Tag

3

About MirrorView

Remote Mirroring

Software

This chapter introduces EMC MirrorView software — mirroring software that works on FC4700 Fibre Channel disk-array storage systems to create a byte-for-byte copy of one or more local LUNs connected to a distant computer system.

Topics are

• What Is EMC MirrorView Software? ..............................................3-2

• MirrorView Features and Benefits...................................................3-4

• How MirrorView Handles Failures.................................................3-5

• MirrorView Example .........................................................................3-7

• MirrorView Planning Worksheet.....................................................3-9

About MirrorView Remote Mirroring Software 3-1

3


What Is EMC MirrorView Software?

EMC MirrorView is a software application that maintains a copy image of a logical unit (LUN) at separate locations. The images are far enough apart to provide for disaster recovery; that is, to let one image continue if a serious accident or natural disaster disables the other.

The production image (the one mirrored) is called the primary image; the copy image is called the secondary image. The primary image is connected to a server called the production host. The secondary image is maintained by a separate storage system that can be a stand-alone storage system or connected to its own server. Both storage systems are managed by the same management station, which can promote the secondary image if the primary becomes inaccessible.



3


File Server Mail Server

Operating system A

Operating system A

The following figure shows two sites and a primary and secondary image that includes one LUN. Notice that the storage-system SP As and SP Bs are connected.

Database

Server 1

Operating system B

Accounts

Server

Operating system A

Database

Server 2

Operating system B

Switch fabric Switch fabric Switch fabric Switch fabric

Cluster

Storage

Group

Database

Server

Storage

Group

SP A SP B

LUN

LUN

LUN

LUN

LUN

LUN

LUN

Extended Distance Connections

Accounts Server

Storage Group

Database Server

Remote Mirror

SP A SP B

LUN

LUN

LUN

LUN

LUN

LUN

LUN

Storage system 1

Figure 3-1


EMC2000

Sites with MirrorView Primary and Secondary Images

The connections between storage systems require fibre channel cable and GigaBit Interface Converters (GBICs) at each SP. If the connections include extender boxes, then the distance between storage systems can be up to the maximum supported by the extender — generally 40-60 kilometers.

Without extender boxes, the maximum distance is 500 meters.

What Is EMC MirrorView Software?

3-3

3


MirrorView Features and Benefits

MirrorView mirroring adds value to customer systems by offering the following features:

• Provision for disaster recovery with minimal overhead

• Local high availability

• Cross mirroring

• Integration with EMC SnapView LUN snapshot copy software

Provision for Disaster Recovery with Minimal Overhead

Provision for disaster recovery is the major benefit of MirrorView mirroring. Destruction of the primary data site would cripple or ruin many organizations. MirrorView lets data processing operations resume within a working day.

MirrorView is transparent to servers and their applications. Server applications do not know that a LUN is mirrored, and the effect on performance is minimal.

MirrorView uses synchronous writes, which means that server writes are acknowledged only after all secondary storage systems commit the data. This type of mirroring is in use by most disaster recovery systems sold today.

MirrorView is not server-based, therefore it uses no server I/O or

CPU resources. The mirror processing is performed on the storage system.

3-4

Local High Availability

MirrorView operates in a highly available environment. There are two host bus adapters (HBAs) per host, and there are two SPs per storage system. If a single adapter or SP fails, the path in the surviving SP can take control of (trespass) any LUNs owned by the failed adapter or SP. The high availability features of RAID protect against disk failure. Mirrors are resilient to an SP failure in the primary or secondary storage system.

Cross Mirroring

The primary or secondary role applies to just one remote mirror. A storage system can maintain a primary image with one mirror and a secondary image with another mirror. This allows the use of server



3 resources at both sites while maintaining duplicate copies of all data at both sites.

Integration with EMC SnapView LUN Copy Software

EMC SnapView software allows users to create a snapshot copy of an active LUN at any point in time. The snapshot copy is a consistent image that can serve for backup while I/O continues to the original

LUN. You can use SnapView in conjunction with MirrorView to make a backup copy at a remote site.

A common situation for disaster recovery is to have a primary and a secondary site that are geographically separate. MirrorView ensures that the data from the primary site replicates to the secondary site.

The secondary site sits idle until there is a failure of the primary site.

With the addition of SnapView at the secondary site, the secondary site can take snapshot copies of the replicated images and back them up to other media, providing time-of-day snapshots of data on the production host with minimal overhead.

How MirrorView Handles Failures

When a failure occurs during normal operations, MirrorView implements several actions to recover.

Primary Image Failure

When the server or storage system running the primary image fails, access to the mirror stops until a secondary is promoted to primary or until the primary is repaired. If promotion occurred, then the primary was demoted to secondary and it must be synchronized before rejoining the mirror. If the primary was repaired, then the mirror continues as before the failure.

For fast synchronization of the images after a primary failure,

MirrorView provides a write-intent log feature. The write intent log records the current activity so that a repaired primary need only copy over data that recently changed (instead of the entire image), thus greatly reducing the recovery time.

How MirrorView Handles Failures 3-5

3


Secondary Image Failure

Table 3-1

A secondary image failure may bring the mirror below the minimum number of images required; if so, this triggers a mirror failure. When a primary cannot communicate with a secondary image, it marks the secondary as unreachable and stops trying to write to it. However, the secondary image remains a member of the mirror.

The primary also attempts to minimize the amount of work required to synchronize the secondary after it recovers. It does this by

fracturing the mirror. This means that, while the secondary is unreachable, the primary keeps track of all write requests so that only those blocks that were modified need to be copied to the secondary during recovery. When the secondary is repaired, the software writes the modified blocks to it, and then starts mirrored writes to it.

The following table shows how MirrorView might help you recover from system failure at the primary and secondary sites. It assumes that the mirror is active and is in the in-sync or consistent state.

MirrorView Recovery Scenarios

Event

Server or storage system running primary image fails.

Storage system running secondary image fails.

Result and recovery

Option 1 - Catastrophic failure, repair is difficult or impossible.

The mirror goes to the attention state. If a host is attached to the secondary storage system, the administrator promotes secondary image, and then takes other prearranged recovery steps required for application startup on standby host.

Note: Any writes in progress when the primary image fails may not propagate to the secondary image. Also, if the remote image was fractured at the time of the failure, any writes since the fracture will not have propagated.

Option 2 -Non-catastrophic failure, repair is feasible.

The mirror goes to the attention state. The administrator has the problem fixed, and then synchronizes the secondary image. The write intent log, if used, shortens the sync time needed. If a write intent log is not used, or the secondary LUN was fractured at the time of failure, then a full synchronization is necessary.

The mirror goes to attention state, rejecting I/O. The administrator has a choice: If the secondary can easily be fixed (for example, if someone pulled out a cable), then the administrator can have it fixed and let things resume. If the secondary can't easily be fixed, the administrator can reduce the minimum number of secondary images required to let the mirror become active. Later, the secondary can be fixed and the minimum number of required images can be changed.


MirrorView Example



Operating system A

Operating system A

Database

Server 1

Operating system B


3

Accounts

Server

Operating system A

Database

Server 2

Operating system B



Cluster

Storage

Group

Database

Server

Storage

Group

SP A SP B

LUN

LUN

LUN

LUN

LUN

LUN

LUN


Extended Distance Connections

Accounts Server

Storage Group

Database Server

Remote Mirror

SP A SP B

LUN

LUN

LUN

LUN

LUN

LUN

LUN


EMC2000

Figure 3-2 Sample MirrorView Configuration

In the figure above, Database Server 1, the production host, executes customer applications. These applications access data on

Storage system 1, in the database server Storage Group.

Storage system 2 is 40 km away and mirrors the data on the database server Storage Group. The mirroring is synchronous, so that

Storage system 2 always contains all data modifications that are acknowledged by Storage system 1 to the production host.

Each server has two paths — one through each SP — to each storage system. If a failure occurs in a path, then the storage-system software

MirrorView Example 3-7

3

About MirrorView Remote Mirroring Software may switch to the path through the other SP (transparent to any applications).

The server sends a write request to an SP in Storage-system 1, which then writes data to its LUN. Next, the data is sent to the corresponding SP in Storage-system 2, where it is stored on its LUN before the write is acknowledged to the production host.

Database server 2, the standby host, has no direct access to the mirrored data. (There need not be a server at all at the standby site; if there is none, the LAN connects to the SPs as shown.) This server runs applications that access other data stored on Storage system 2. If a failure occurs in either the production host or Storage system 1, an administrator can use the management station to promote the image on Storage-system 2 to the primary image. Then the appropriate applications can start on any connected server (here,

Database server 2) with full access to the data. The mirror will be accessible in minutes, although the time needed for applications to recover will vary.



3

MirrorView Planning Worksheet

To plan, you must decide whether you want to use a write intent log and, if so, the LUNs you will bind for this. You will also need to complete a MirrorView mirroring worksheet.

Note that you must assign each primary image LUN to a Storage

Group (as with any normal LUN), but must not assign a secondary image LUN to a Storage Group.

MirrorView Mirroring Worksheet

Production host name

Primary LUN ID, size, and file system name

Storage

Group

Number/Name

Use Write Intent

Log - Y/N (about

256 Mbytes per storage system)

SP

(A/B)

Remote mirror name

Secondary image contact person

Secondary image LUN ID

What Next?

This chapter explained the MirrorView remote mirroring software.

For information on SnapView snapshot copy software, continue to

the next chapter. To plan LUNs and file systems, skip to Chapter 5.

For details on the storage-system hardware, skip to Chapter 6. For

storage-system management utilities, skip to Chapter 7.

MirrorView Planning Worksheet 3-9

3



nvisible Body Tag

4

About SnapView

Snapshot Copy

Software

This chapter introduces EMC SnapView software that creates LUN snapshots to be used for independent data analysis or backup with

EMC FC 4700 Fibre Channel disk-array storage systems.

Major sections are

• What Is EMC SnapView Software? .................................................4-2

• Sample Snapshot Session ..................................................................4-4

• Snapshot Planning Worksheet .........................................................4-5

About SnapView Snapshot Copy Software 4-1

4


What Is EMC SnapView Software?

EMC SnapView is a software application that captures a snapshot image of a LUN and retains the image independently of subsequent changes to the LUN. The snapshot image can serve as a base for decision support, revision testing, backup, or in any situation where you need a consistent, copyable image of real data.

SnapView can create or destroy a snapshot in seconds, regardless of the LUN size, since it does not actually copy data. The snapshot image consists of the unchanged LUN blocks and, for each block that changes from the snapshot moment, a copy of the original block. The software stores the copies of original blocks in a private LUN called the snapshot cache. For any block, the copy happens only once, when the block is first modified. In summary: snapshot copy = unchanged-blocks-on-source-LUN + blocks-cached

As time passes, and I/O modifies the source LUN, the number of blocks stored in the snapshot cache grows. However, the snapshot copy, composed of all the unchanged blocks — some from the source

LUN and some from the snapshot cache — remains unchanged.

The snapshot copy does not reside on disk modules like a conventional LUN. However, the snapshot copy appears as a conventional LUN to another host. Any other server can access the copy for data processing analysis, testing, or backup.

The following figure shows how a snapshot session works: the production host with the source LUN, the snapshot cache, and second host with access to the snapshot copy.



4

Production host

Continuous

I/O

Storage system

Second host

Source

LUN

The snapshot is a composite of source LUN and cache data that is accessible as long as the session lasts.

Snapshot

Figure 4-1

EMC1822

SnapView Operations Model

SnapView offers several important benefits:

• It allows full access to production data with minimal impact on performance;

• For decision support or revision testing, it provides a coherent, readable and writable copy of real production data at any given point in time; and

• For backup, it practically eliminates the time that production data spends offline or in hot backup mode. And it off-loads the backup overhead from the production host to another host.

Snapshot Components

A snapshot session uses three components: a production host, a second host, and a snapshot copy session.

• The production host runs the customer applications on the LUN that you want to copy, and allows the management software to create, start, and stop snapshot sessions.

• The second host reads the snapshot during the snapshot session, and performs analysis or backup using the snapshot.

• A snapshot session makes the snapshot copy accessible to the second host; it starts and stops according to directives you give using Navisphere software on the production host.

What Is EMC SnapView Software?

4-3

4


Sample Snapshot Session

The following figure shows how a sample snapshot session starts, runs, and stops.

1. Before session starts

Production

Host

Second

Host

2. At session start (2:00 p.m.)

Production

Host

Second

Host

3. At start of operation (2:02 p.m.)

Production host

Second host

Source

LUN

Snapshot cache

Snapshot Source

LUN

Cache Snapshot Source

LUN

Cache Snapshot

(pointers to chunks)

4. At end of operation (4:15 p.m.)

Production

Host

Second

Host

5. At session end (4:25 p.m.)

Production

Host

Second

Host

Source

LUN Cache

Snapshot

(pointers to chunks)

Source

LUN

Cache Snapshot

Key:

Unchanged chunks on source LUN

Changed chunks on source LUN

Unchanged chunks in cache and snapshot

Figure 4-2 How a Snapshot Session Starts, Runs, and Stops

EMC1823



4

Snapshot Planning Worksheet

The following information is needed for system setup to let you bind one or more LUNs for the snapshot cache.

Snapshot Cache Setup Information (For Binding)

Snapshot source LUN size SP

A

B

RAID type for snapshot cache

RAID Group ID of parent RAID

Group

LUN size (Mbytes, we suggest 20% of source LUN size)

Cache LUN ID

(complete after binding)

For each session, you must complete a snapshot session worksheet.

Note that you must assign the LUN and snapshot to different Storage

Groups. One Storage Group should include the production host and source LUN; another Storage Group should include the second host and the snapshot.

Snapshot Session Worksheet

Production host name LUN ID

Storage

Group

ID

Size

(Mb)

Application, file system, or database name LUN ID

Size

(Mb)

Chunk

(cache write) size

SP

(both

LUN and cache)

Time of day to copy

Session name

Snapshot Planning Worksheet 4-5

4


What Next?

This chapter explained the SnapView snapshot copy software. To plan LUNs and file systems, continue to the next chapter. For details

on the storage-system hardware, skip to Chapter 6. For

storage-system management utilities, skip to Chapter 7.


Invisible Body Tag

5


This chapter shows a sample RAID, LUN, and Storage Group installation with sample shared switched and unshared direct storage, and then provides worksheets for planning your own storage installation. Topics are

• Multiple Paths to LUNs ....................................................................5-2

• Sample Shared Switched Installation..............................................5-3

• Sample Unshared Direct Installation ..............................................5-7

• Planning Applications, LUNs, and Storage Groups .....................5-8

Planning File Systems and LUNs 5-1

5


Multiple Paths to LUNs

A shared storage system includes one or more servers, two Fibre

Channel switches, one or more storage systems, each with two SPs and the Access Logix option.

With shared storage (switched or direct), there are at least two paths to each LUN in the storage system. The storage-system Base Software detects both paths and, using optional Application Transparent

Failover (ATF) software, can automatically switch to the other path, without disrupting applications, if a device (such as a host-bus adapter or cable) fails.

With unshared storage (one server direct connection), if the server has two adapters and the storage system has two SPs, ATF performs the same function as with shared systems: automatically switches to the other path if a device (such as host bus adapter or cable) fails.

And with two adapters and two SPs (switched or unshared), ATF can send I/O to each available paths in round-robin sequence (multipath

I/O) for dynamic load sharing and greater throughput.



5

Sample Shared Switched Installation

The following figure shows a sample shared storage system connected to three servers: two servers in a cluster and one server running a database management program.

Disk IDs have the form b e d, where b is the FC4700 back-end bus number (0, which can be omitted, or 1), e is the enclosure number, set on the enclosure front panel (always 0 for the DPE), and d is the disk position in the enclosure (left is 0, right is 9).

Sample Shared Switched Installation 5-3

5



Database Server (DS) File Server (FS)

Operating system B

Operating system A

Mail Server (MS)

Operating system B


Private storage

Cluster

Storage

Group

Database

Server

Storage

Group

SP A

Unbound disks

SP B

Disk IDs

030-039

FS R5

Apps

FS R5

Users

FS R5

Files A

MS R5

Users

FS R5

Files B

MS R5

ISP A mail

MS R5

ISP B mail

MS R5

Specs

DS R5

Users

DS R5

Dbase2

120-129

020-029

110-119

010-019

100-109

DS R1

Log D1

DS R1

Log D2

DS R5

(6 disks)

Dbase1

000-009

Path 1

Path 2

EMC1824

Figure 5-1 Sample Shared Switched Storage Configuration



5

The storage-system disk IDs and Storage Group LUNs are as follows.

Clustered System LUNs

Database Server LUNs (DS) - SP A

File Server LUNs (FS) - SP B

Disk IDs RAID type, storage type

010-014 RAID 5, Applications

015-019 RAID 5, Users

110-114 RAID 5, ISP A mail

115-119 RAID 5, ISP B mail

Mail Server LUNs (MS) - SP A


000,001 RAID 1, Log file for database Dbase1

002, 003 RAID 1, Log file for database Dbase2

004-009 RAID 5 (6 disks), Dbase1


105-109 RAID 5, Dbase2

020, 021 – Hot spare (automatically replaces a failed disk in any server’s LUN)


020-024 RAID 5, Files A

025-029 RAID 5, Files B


125-129 RAID 5, Specs

With 36-Mbyte disks, the LUN storage capacities and drive names are as follows.

Database Server — 540 Gbytes on four LUNs

DS R5

Users

Unit users on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for user directories.

DS R5

Dbase2

DS R1

Log 1

Unit dbase2 on five disks bound as a RAID 5 Group for 144 Gbytes of storage; for the second database system.

Unit logfDbase1 on two disks bound as a RAID 1 mirrored pair for 36 Gbytes of storage; for database 1 log files.

DS R1

Log 2

DS R5

Dbase1

Unit logfDbase2 on two disks bound as a RAID 1 mirrored pair for 36 Gbytes of storage; for database 2 log files.

Unit dbase on six disks bound as a RAID 5 Group for

180 Gbytes of storage; for the database 1 system.

Sample Shared Switched Installation 5-5

5


File Server — 576 Gbytes on four LUNs.

FS R5

Apps

Unit S on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for applications.

FS R5

Users

FS R5

FilesA

FS R5

FilesB

Unit T on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for user directories and files.

Unit U on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for file storage.

Unit V on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for file storage.

Mail Server — 576 Gbytes on four LUNs

MS R5

Users

Unit Q on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for user directories and files.

MS R5

Specs

MS R5

ISP mail

MS R5

ISP mail

Unit R on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for specifications.

Unit O on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for the mail delivered via ISPA.

Unit P on five disks bound as a RAID 5 Group for

144 Gbytes of storage; for the mail delivered via ISP B.



5

Sample Unshared Direct Installation

This section shows the disks and LUNs in an unshared direct storage-system installation.

To repeat from the previous section: disk IDs have the form b e d, where b is the FC4700 back-end bus number (0, which can be omitted, or 1), e is the enclosure number, set on the enclosure front panel

(always 0 for the DPE), and d is the disk position in the enclosure (left is 0, right is 9).

Server

Disk IDs

100-109

010-019

SP A

Database

RAID 5

Sys

RAID 1

SP B

Users

RAID 5

Clients, mail

RAID 5

Path 1

Path 2

EMC1825

Figure 5-2 Unshared Direct Storage Example

If each disk holds 36 Gbytes, then the storage system provides the server with 576 Gbytes of disk storage, all highly available; it provides Server 2 with 180 Gbytes of storage, all highly available. The storage-system disk IDs and LUNs are as follows.

LUNs - SP A and SP B, 576 Gbytes

Disk IDs RAID type, storage type, capacity

000, 001 RAID 1, System disk, 36 Gbytes

002-009 RAID 5 (8 disks), Clients and Mail, 252 Gbytes

100-104 RAID 5, Database, 144Gbytes

105-109 RAID 5, Users, 144 Gbytes

Sample Unshared Direct Installation 5-7

5


Planning Applications, LUNs, and Storage Groups

This section helps you plan your storage use — the applications to run, the LUNs that will hold them, and, for shared storage, the

Storage Groups that will belong to each server. The worksheets to help you do this include

• Application and LUN planning worksheet — lets you outline your storage needs.

• LUN and Storage Group planning worksheet — lets you decide on the disks to compose the LUNs and the LUNs to compose the

Storage Groups for each server.

Unshared storage systems do not use Storage Groups. For unshared storage, on the LUN and Storage Group worksheet, skip the Storage

Group entry.

• LUN details worksheet — lets you plan each LUN in detail.

Make as many copies of each blank worksheet as you need. You will need this information later when you configure the storage system(s).

Sample worksheets appear later in this chapter.

Application and LUN Planning

Use the following worksheet to list the applications you will run, and the RAID type and size of LUN to hold them. For each application that will run, write the application name, file system (if any), RAID type, LUN ID (ascending integers, starting with 0), disk space required, and finally the name of the servers and operating systems that will use the LUN.



5

Application and LUN Planning Worksheet

Application

File system, partition, or drive

RAID type of

LUN

LUN

ID (hex)

Disk space required

(Gbytes)

Server hostname and operating system

Application

Users

Dbase2

Log file for

Dbase1

Log file for

Dbase2

Dbase1

A sample worksheet begins as follows:

File system, partition, or drive

RAID type of

LUN

RAID 5

RAID 5

RAID 1

0

0

LUN

ID (hex)

0

RAID 1 1

Disk space required

(Gbytes)

72 GB

72 GB

18 GB

18 GB

Server hostname and operating system

Server1,UNIX

Server1,UNIX

Server1,UNIX

Server1,UNIX

RAID 1/0 2 90 GB Server2,UNIX

Completing the Application and LUN Planning Worksheet

Application . Enter the application name or type.

File system, partition , or drive. Write the drive letter (for Windows only) and the partition, file system, logical volume, or drive letter name, if any.

With a Windows operating system, the LUNs are identified by drive letter only. The letter does not help you identify the disk configuration (such as RAID 5). We suggest that later, when you use

Planning Applications, LUNs, and Storage Groups 5-9

5

Planning File Systems and LUNs the operating system to create a partition on a LUN, you use the disk administrator software to assign a volume label that describes the

RAID configuration. For example, for drive T, assign the volume ID

RAID5_T. The volume label will then identify the drive letter.

RAID type of LUN . This is the RAID Group type you want for this partition, file system, or logical volume. The features of RAID types

are explained in Chapter 3. For a RAID 5, RAID 1, RAID 1/0, and

RAID 0 Group, you can create one or more LUNs on the RAID

Group. For other RAID types, you can create only one LUN per RAID

Group.

LUN ID. The LUN ID is a hexadecimal number assigned when you bind the disks into a LUN. By default, the ID of the first LUN bound is 0, the second 1, and so on. Each LUN ID must be unique within the storage system, regardless of its Storage Group or RAID Group.

The maximum number of LUNs supported on one host-bus adapter depends on the operating system.

Disk space required (Gbytes) . Consider the largest amount of disk space this application will need, and then add a factor for growth.

Server hostname and operating system . Enter the server hostname

(or, if you don’t know the name, a short description that identifies the server) and the operating system name, if you know it.

LUN and Storage Group Planning Worksheet

Use the following worksheet to select the disks that will make up the

LUNs and Storage Groups in each storage system. A storage system is any group of enclosures connected to a DPE; it can include up to nine DAE enclosures for a total of 100 disks. A storage system can include up to 100 disks.

Unshared storage systems do not use Storage Groups. For unshared storage, skip the Storage Group entry.



5

Bus 0 enclosures

LUN and Storage Group Planning Worksheet

0 4 0 0 4 1 0 4 2 0 4 3 0 4 4 0 4 5 0 4 6 0 4 7 0 4 8 0 4 9

DAE

1 3 0 1 3 1 1 3 2 1 3 3 1 3 4 1 3 5 1 3 6 1 3 7 1 3 8 1 3 9

DAE

0 3 0 0 3 1 0 3 2 0 3 3 0 3 4 0 3 5 0 3 6 0 3 7 0 3 8 0 3 9

DAE

1 2 0 1 2 1 1 2 2 1 2 3 1 2 4 1 2 5 1 2 6 1 2 7 1 2 8 1 2 9

DAE

0 2 0 0 2 1 0 2 2 0 2 3 0 2 4 0 2 5 0 2 6 0 2 7 0 2 8 0 2 9

DAE

1 1 0 1 1 1 1 1 2 1 1 3 1 1 4 1 1 5 1 1 6 1 1 7 1 1 8 1 1 9

DAE

0 1 0 0 1 1 0 1 2 0 1 3 0 1 4 0 1 5 0 1 6 0 1 7 0 1 8 0 1 9

DAE

1 0 0 1 0 1 1 0 2 1 0 3 1 0 4 1 0 5 1 0 6 1 0 7 1 0 8 1 0 9

Bus 1 enclosures

DAE

0 0 0

0 0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9

DPE

Navisphere Manager displays disk IDs as n-n-n

CLI recognizes disk IDs as n_n_n

Storage-system number or name:_______________

Storage Group ID or name:______ Server hostname:_________________ Dedicated Shared

LUN ID or name_______RAID type ___ Cap. (Gb) _____ Disk IDs_____________________________________















5


Part of a sample LUN and Storage Group worksheet follows.

LUN 3

RAID 5

1 0 0 1 0 1 1 0 2 1 0 3 1 0 4 1 0 5 1 0 6 1 0 7 1 0 8 1 0 9

LUN 0

RAID 1

0 0 0

DAE

0 0 1 0 0 2 0 0 3 0 0 4 0 0 5

0 0 6 0 0 7 0 0 8 0 0 9

DPE

LUN 1

RAID 1

LUN 4

RAID 5

LUN 2

RAID 5

Storage-system number or name:_______________

Storage Group ID or name:______ Server hostname:_____________________ Dedicated Shared

0

1

0

1

1

18

18

Server1

000, 001

002, 003

X

LUN ID or name_______RAID type ___ Cap. (Gb) _____ Disk IDs_________________________________________

2

3

5 90

72

004,005,006,007,008,009

100,101,102,103,104,105

X

4 5 72




Storage Group ID or name:______ Server hostname:_____________________ Dedicated Shared





Completing the LUN and Storage Group Planning Worksheet

As shown, draw circles around the disks that will compose each

LUN, and within each circle specify the RAID type (for example,

RAID 5) and LUN ID. This is information you will use to bind the disks into LUNs. For disk IDs, use the form shown. This form is

enclosure_diskID, where enclosure is the enclosure number (the bottom one is 0, above it 1, and so on) and diskID is the disk position (left is 0, next is 1, and so on).

None of the disks 000 through 008 may be used as a hot spare.

Next, complete as many of the Storage System sections as needed for all the Storage Groups in the SAN (or as needed for all the LUNs with unshared storage). Copy the (blank) worksheet as needed.



5

For shared storage, if a Storage Group will be dedicated (not accessible by another server in a cluster), mark the Dedicated box at the end of its line; if the Storage Group will be accessible to one or more other servers in a cluster, write the hostnames of all servers and mark the Shared box.

For unshared storage, ignore the Dedicated/Shared boxes.

LUN Details Worksheet

Use the LUN details worksheet to plan the individual LUNs. Blank and sample completed LUN worksheets follow.

Complete as many blank worksheets as needed for all LUNs in storage systems. For unshared storage, skip the Storage Group entries.


5



Storage system (complete this section once for each storage system)

Storage-system number or name:______

Storage-system installation type

❏ Unshared Direct o Shared-or-Clustered Direct ❏ Shared Switched

SP information: SP A: IP address or hostname:_______Port ALPA ID:_____ Memory(Mbytes):_____

SP B: IP address or hostname:_______Port ALPA ID:_____ Memory(Mbytes):_____

❏ Caching Read cache size:__ MBWrite cache size: __ MB

❏ RAID-3

Cache page size (Kbytes):___

LUN ID:_____ SP owner: ❏ A ❏ B SP bus (0 or 1):___

RAID Group ID: Size,GB: LUN size,GB: Disk IDs:

RAID type: ❏ RAID 5

❏ RAID 1/0

❏

❏

RAID 3 - Memory, MB:___

Individual disk

Caching: ❏ Read and write ❏ Write ❏ Read ❏ None

Servers that can access this LUN’s Storage Group:

Operating system information: Device name:

❏

❏

RAID 1 mirrored pair

Hot spare

❏

File system, partition, or drive:

RAID 0

LUN ID:_____ SP owner: ❏ A ❏ B SP bus (0 or 1):___

RAID Group ID: Size, GB: LUN size,GB: Disk IDs:


❏ RAID 1/0

❏

❏


Individual disk



❏ RAID 1 mirrored pair ❏ RAID 0

❏ Hot spare

Operating system information: Device name: File system, partition, or drive:

LUN ID:_____ SP owner: ❏ A ❏ B SP bus (0 or 1):__ _

RAID Group ID: Size,GB: LUN size,GB: Disk IDs:


❏ RAID 1/0

❏

❏


Individual disk



❏ Hot spare


Operating system information: Device name: File system, partition, or drive:



5


Storage system (complete this section once for each storage system)

Storage-system number or name:__ SS1 ____

Storage-system installation type

X Unshared Direct ❏ Shared-or-Clustered Direct ❏ Shared Switched

SP information: SP A: IP address or hostname:__ SS1spa _Port ALPA ID:__ 0 _ Memory(Mbytes):_ 256 __

SP B: IP address or hostname:__ SS1spb _Port ALPA ID:_ 1 ___ Memory(Mbytes):_ 256 __

❏ Caching Read cache size:_ 80 _ MBWrite cache size:_ 160 _ MB

❏ RAID-3

Cache page size (Kbytes):_ 2 _

LUN ID:__ 0 __ SP owner: ❏ A ❏ B SP bus (0 or 1):_ 0 __

RAID Group ID: 0 Size,GB: 18 LUN size,GB: 18 Disk IDs:


❏ RAID 1/0

❏

❏


Individual disk


Servers that can access this LUN’s Storage Group: Server1

000, 001

X RAID 1 mirrored pair ❏ RAID 0

❏ Hot spare

2

Operating system information: Device name: File system, partition, or drive: V

LUN ID:__ 1 ___ SP owner: ❏ A ❏ B SP bus (0 or 1):___

002, 003

RAID Group ID: 1 Size,GB: 18 LUN size,GB: 18 Disk IDs:


❏ RAID 1/0

❏

❏


Individual disk


X RAID 1 mirrored pair ❏ RAID 0

X

Hot spare


Operating system information: Device name: File system, partition, or drive: T

LUN ID:__ 2 ___ SP owner: ❏ A ❏ B SP bus (0 or 1):__ 1 _

RAID Group ID: 2 Size, GB: 72 LUN size,GB: 72 Disk IDs: 104,105,106,107,108,109

RAID type: X RAID 5

❏ RAID 1/0

❏ RAID 3 - Memory, MB:___

❏ Individual disk



❏ Hot spare


Operating system information: Device name: File system, partition, or drive: U


5


Competing the LUN Details Worksheet

Complete the header portion of the worksheet for each storage system as described next. Copy the blank worksheet as needed.

Storage-System Entries

Storage-system installation type: specify Unshared Direct,

Shared-or-Clustered Direct, or Shared Switched.

SP information: IP address or hostname. The IP address is required for communication with the SP. You don’t need to complete it now, but you will need it when the storage system is installed so that you can set up communication with the SP.

Port ALPA ID. This must be unique for each SP in a storage system. The SP Port ALPA ID, like the IP address, is generally set at installation. One easy way to do this is to set SP Port 0 to ALPA

ID 0 and SP 1 Port 1 to ALPA Port 1.

Memory (Mbytes) . Each SP can have 256 or 512 Mbytes of memory.

Caching. You can use SP memory for read/write caching or

RAID 3. (Using both caching and RAID 3 in the same storage system is not recommended.) You can use different cache settings for different times of day. For example, for user I/O during the day, use more write cache; for sequential batch jobs at night, use more read cache. You enable caching for specific LUNs — allowing you to tailor your cache resources according to priority.

If you choose caching, check the box and continue to the next cache item; for RAID 3, skip to the LUN ID entries.

Read cache size.

If you want a read cache, it should generally be about one third of the total available cache memory.

Write cache size.

The write cache should be two thirds of the total available. Some memory is required for system overhead, so you cannot determine a precise figure at this time. For example, for

256 Mbytes of total memory, you might have 240 Mbytes available, and you would specify 80 Mbytes for the read cache and 160 Mbytes for the write cache.

Cache page size. This applies to both read and write caches. It can be 2, 4, 8, or 16 Kbytes.

As a general guideline, we suggest 8 Kbytes. The ideal cache page size depends on the operating system and application.



5

RAID 3 . If you want to use the SP memory for RAID 3, check the box.

RAID Group/LUN Entries

Complete a RAID Group/LUN entry for each LUN and hot spare.

LUN ID . The LUN ID is a hexadecimal number assigned when you bind the disks into a LUN. By default, the ID of the first LUN bound is 0, the second 1, and so on. Each LUN ID must be unique within the storage system, regardless of its Storage Group or

RAID Group.

The maximum number of LUNs supported on one host-bus adapter depends on the operating system.

SP owner . Specify the SP that will own the LUN: SP A or SP B.

You can let the management program automatically select the SP to balance the workload between SPs; to do so, leave this entry blank.

SP bus (0 or 1).

Each FC4700 SP has two back-end buses, 0 and 1.

Ideally, you will place the same amount of load on each bus. This may mean placing two or three heavily-used LUNs on one bus, and six or eight lightly used LUNs on the other bus. The bus designation appears in the disk ID (form bus-enclosure-disk). For disks on bus 0, you can omit the bus designation from the disk ID; that is, 0-1-3 and 1-3 both indicate the disk on bus 0, in enclosure

1, in the third position (fourth from left) in the storage system.

RAID Group ID . This ID is a hexadecimal number assigned when you create the RAID Group. By default, the number of the first RAID Group in a storage system is 0, the second 1, and so on, up to the maximum of 1F (31).

Size (RAID Group size). Enter the user-available capacity in gigabytes (Gbytes) of the whole RAID Group. You can determine the capacity as follows:

RAID5 or RAID-3 Group: disk-size * (number-of-disks - 1)

RAID 1/0 or RAID-1 Group: (disk-size * number-of-disks) / 2

RAID 0 Group:

Individual unit: disk-size * number-of-disks disk-size


5


For example,

• A five-disk RAID 5 or RAID 3 Group of 18-Gbyte disks holds

72 Gbytes;

• An eight-disk RAID 1/0 Group of 18-Gbyte disks also holds

72Gbytes;

• A RAID 1 mirrored pair of 18-Gbyte disks holds 18 Gbytes; and

• An individual disk of an 18-Gbyte disk also holds 18 Gbytes.

Each disk in the RAID Group must have the same capacity; otherwise, you will waste disk storage space.

LUN size . Enter the user-available capacity in gigabytes (Gbytes) of the LUN. You can make this the same size as the RAID Group, described previously. Or, for a RAID 5, RAID 1, RAID 1/0, or

RAID 0 Group, you can make the LUN smaller than the RAID

Group. You might do this if you wanted a RAID 5 Group with a large capacity and wanted to place many smaller capacity LUNs on it; for example, to specify a LUN for each user. However, having multiple LUNs per RAID Group may adversely impact performance. If you want multiple LUNs per RAID Group, then use a RAID Group/LUN series of entries for each LUN.

Disk IDs . Enter the IDs of all disks that will make up the LUN or hot spare. These are the same disk IDs you specified on the previous worksheet. For example, for a RAID 5 Group in the DPE

(enclosure 0, disks 2 through 6), enter 003, 004, 005, 006, and 007.

RAID type . Copy the RAID type from the previous worksheet.

For example, RAID 5 or hot spare. For a hot spare (not strictly speaking a LUN at all), skip the rest of this LUN entry and continue to the next LUN entry (if any).

If this is a RAID 3 Group, specify the amount of SP memory for that group. To work efficiently, each RAID 3 Group needs at least

6 Mbytes of memory.

Caching . If you want to use caching (entry on page 5-16), you can specify whether you want caching — read and write, read, or write for this LUN. Generally, write caching improves performance far more than read caching. The ability to specify caching on a LUN basis provides additional flexibility, since you can use caching for only the units that will benefit from it. Read and write caching recommendations follow.



5

Table 5-1 Cache Recommendations for Different RAID Types

RAID 5 RAID 3

Highly

Recommended

Not allowed

RAID 1 RAID 1/0 RAID 0 Individual Unit

Recommended Recommended Recommended Recommended

What Next?

Servers that can access this LUN’s Storage Group . For shared switched storage or shared-or-clustered direct storage, enter the name of each server (copied from the LUN and Storage Group worksheet). For unshared direct storage, this entry does not apply.

Operating system information: Device name. Enter the operating system device name, if this is important and if you know it. Depending on your operating system, you may not be able to complete this field now.

File system, partition, or drive . Write the name of the file system, partition, or drive letter you will create on this LUN. This is the same name you wrote on the application worksheet.

On the following line, write any pertinent notes; for example, the file system mount- or graft-point directory pathname (from the root directory). If any of this storage system’s LUNs will be shared with another server, and the other server is the primary owner of this LUN, write secondary. (As mentioned earlier, if the storage system will be used by two servers, we suggest you complete one of these worksheets for each server.)

This chapter outlined the LUN planning tasks for storage systems. If you have completed the worksheets to your satisfaction, you are ready to learn about the hardware needed for these systems as

explained in Chapter 6.


5



Invisible Body Tag

6

Storage-System

Hardware

This chapter describes the storage-system hardware components.

Topics are

• Hardware for FC4700 Storage Systems...........................................6-3

• Planning Your Hardware Components ..........................................6-8

• Hardware Data Sheets.......................................................................6-9

• Cabinets for Rackmount Enclosures .............................................6-12

• Cable and Configuration Guidelines ............................................6-13

• Hardware Planning Worksheets ....................................................6-13

Storage-System Hardware 6-1

6


The storage systems attach to the server and the interconnect components as described in Chapter 1. To review the installation types:

• Unshared direct , with one server, is the simplest and least costly;

• Shared-or-clustered direct , with a limit of two servers, lets two servers share storage resources with high availability; and

• Shared switched , which has two switch fabrics, lets two to 15 servers share the resources of several storage systems in a storage area network (SAN).

For FC4700 storage systems, at least one network connection is required.

Unshared Direct

(one or two servers)

Server

Shared or Clustered

Direct (two servers)

Server Server

Shared Switched (multiple servers,

Multiple Paths to SPs)


Server component

Interconnect component


Storage component

SP A SP B

Storage system

Path 1

Path 2

SP A SP B

Storage system

SP A SP B

Storage system

SP A SP B

Storage system

SP A SP B

Storage system

Figure 6-1 Types of Storage-System Installation

EMC1826



6

Hardware for FC4700 Storage Systems

The primary hardware component for FC4700 storage is a ten-slot disk-array processor enclosure (DPE) with two storage processors

(SPs). Each FC4700 SP has two ports (front-end ports for server or switch connection) and two back-end buses that run the disks.

A DPE can support up to nine separate 10-slot enclosures called disk array enclosures (DAEs) for a total of 100 disks.

Storage Hardware — Rackmount DPE-Based Storage Systems

The DPE rackmount enclosure is a sheet-metal housing with a front door, a midplane, and slots for the storage processors (SPs), link control cards (LCCs), disk modules, power supplies, and fan packs.

All components are customer replaceable units (CRUs) that can be replaced under power. The DPE rackmount model looks like the following figure.

Power supplies

LCC

Storage processors

Disk modules

(front door removed for clarity)

Front Rear

Network ports

Disk drive fan pack

LCC

Figure 6-2 DPE Storage-System Components — Rackmount Model

EMC1746

Hardware for FC4700 Storage Systems 6-3

6


A separate standby power supply (SPS) is required to support write caching. All the storage components — rackmount DPE, DAEs, SPSs, and cabinet — are shown in the following figure.

DAE

DAE

DPE

DAE

DAE

DPE

Disks

SPs

Standby power supplies (SPSs)

Front Rear

Figure 6-3 Rackmount Storage System with DPE and DAEs

EMC1744

The disks — available in differing capacities — fit into slots in the enclosure. Each module has a unique ID that you use when binding or monitoring its operation. The ID is derived from the enclosure address (always 0 for the DPE, adjustable on a DAE) and the disk module slot numbers.



6

EMC1829

Figure 6-4 Disk Modules and Module IDs

Storage Processor (SP)

The SP provides the intelligence of the storage system. Using its own proprietary software (called Base Software), the SP processes the data written to or read from the disk modules, and monitors the modules themselves. An SP consists of a printed-circuit board with memory modules (RIMMs), and status lights.

Each FC4700 SP has two front-end ports for server or switch connection, and two back-end buses that run the disks.


6


For high availability, a storage system comes with two SPs. The second SP provides a second route to a storage system and also lets the storage system use write caching (below) for enhanced write performance.


6-6


Path 1

Path 2

SP A SP B

Storage system

SP A SP B

Storage system

EMC1810

Figure 6-5 Shared Storage Systems

There are more examples of storage in Chapter 5.

Storage-System Caching

Storage-system caching improves read and write performance for several types of RAID Groups. Write caching, particularly, helps write performance — an inherent problem for RAID types that require writing to multiple disks. Read and write caching improve performance in two ways:

• For a read request — If a read request seeks information that’s already in the read or write cache, the storage system can deliver it immediately, much faster than a disk access can.

• For a write request — the storage system writes updated information to SP write-cache memory instead of to disk, allowing the server to continue as if the write had actually completed. The disk write occurs from cache later, at the most expedient time. If the request modifies information that’s in the cache waiting to be written to disk, the storage system updates the information in the cache before writing it; this requires just one disk access instead of two.



6

Data in the cache is protected from power loss by a standby power supply (SPS). If line power fails, the SPS provides power to let the storage system write cache contents to the vault disks. The vault disks are standard disk modules that store user data but have space reserved outside operating system control. When power returns, the storage system reads the cache information from the vault disks, and then writes it to the file systems on the disks. This design ensures that all write-cached information reaches its destination.

Vault disks are independent of user data storage; a disk’s role as a vault disk has no affect on its data capacity or performance.

SP Network Connection

Each SP has an Ethernet connection though which the Navisphere

Manager software lets you configure and reconfigure the LUNs and

Storage Groups in the storage system. Each SP connects to a network; this lets you reconfigure, if needed, should one SP fail.


6


Planning Your Hardware Components

This section helps you plan the hardware components — adapters, cables, and storage systems and site requirements — for each server in your installation.

For shared switched storage or shared-or-clustered direct storage, you must use high-availability options: two SPs per storage system and at least two HBAs per server. For shared switched storage, two switch fabrics are required.

For unshared direct storage, a server may have one or two HBAs.

Components for Shared Switched Storage

The minimum hardware configuration required for shared switched storage is two servers, each with two host bus adapters, two Fibre

Channel switch fabrics with one switch per fabric, and two SPs per storage system. Two SPS units (standby power supplies) are also required. You can use more servers (up to 15 are allowed), more switches per fabric, and more storage systems (up to four are allowed).

Components for Shared-or-Clustered Direct Storage

The minimum hardware required for shared switched or shared-or-clustered direct storage is two servers, each with two host bus adapters, and one storage system with two SPs. You can use more storage systems (up to four are allowed).

Components for Unshared Direct Storage

The minimum hardware required for unshared direct storage is one server with two host bus adapters and one storage system with two

SPs.You can choose more storage systems (up to four are allowed).



6

Hardware Data Sheets

The hardware data sheets shown in this section provide the plant requirements, including dimensions (footprint), weight, power requirements, and cooling needs, for DPE and rackmount DAE disk systems. Sections on cabinets and cables follow the data sheets.

DPE Data Sheet

The rackmount DPE is the heart of a storage system. Its dimensions and requirements are shown in the following figure.

Rackmount DPE Dimensions and Requirements

Depth

70 cm

(27.6 in.)

Width

44.5 cm

(17.5 in.)

Height

28.6 cm

(11.3 in.)

6.5 U

DPE

SPS mounting tray

Tray depth

51.4 cm

(20.2 in.)

Tray height

4.44 cm

(1.75 in.)

1 U

EMC1830

Weight (without packaging)

Maximum (max disks, SPs, LCCs, PSs): with 2 SPSs

Power requirements

Voltage rating

Rackmount

55 kg (121 lb)

77 kg (169 lb)

100 V ac to 240 V ac –10%/+15%, single phase, 47 Hz to 63 Hz; power supplies are auto ranging

Hardware Data Sheets 6-9

6



Current draw

Power consumption

At 100 v ac input – Deskside DPE/DAE: 12.0

A; Rackmount DPE: 8.0 A max SPS: 1.0 A max per unit during charge

Deskside DPE/DAE: 1200 VA

Rackmount DPE: 800 VA max SPS: 100 VA per unit during charge

Power cables (single or dual) ac inlet connector

Deskside power cord

IEC 320-C14 power inlet

USA

Outside USA

1.8 m (6.0 ft): NEMA

6-15P plug

Specific to country

Operating environment

Temperature

Relative humidity

Altitude

Heat dissipation (max)

10 o C to 40 o C (50 o

Deskside DPE/DAE: 4115x10 3 J/hr (3900 BTU/hr) max estimated

Rackmount DPE: 2736x10 3 J/hr (2594 BTU/hr) max estimated

Front to back

F to 104 o F)

Non-condensing, 20% to 80%

40 o C to 2,438 m (8,000 ft); 37 o C to 3,050 m (10,000 ft)

Air flow

Service clearances

Front

Back

30.3 cm (1 ft)

60.6 cm (2 ft)


DAE Data Sheet


6

The rackmount DAE storage-system dimensions and requirements are shown in the following figure.

Rackmount DAE Dimensions and Requirements

Depth

63 cm

(24.9 in.)

Width

44.5 cm

(17.5 in.)

Height

15.4 cm

(6.1 in.)

3.5 U

Weight (without packaging) Deskside 30

Maximum (max disks, SPs) 144 kg (316 lb)

EMC1831

Deskside 10

60 kg (132 lb)

Rackmount

35.4 kg (78 lb)


Voltage rating

Current draw

Power consumption

Operating environment

Temperature

Relative humidity

Altitude

Heat dissipation (max)

Air flow

Service clearances

Front

Back

100 V ac to 240 V ac -10%+/15%, single phase, 47 Hz to

63 Hz; power supplies are auto ranging

At 100 v ac input – 10-slot: 4.0 A

10-slot: 400 VA

10 o C to 40 o C (50 o F to 104 o F)

Non-condensing, 20% to 80%

40 o C to 2,438 m (8,000 ft); 37 o C to 3,050 m (10,000 ft)

30-slot: 4,233 KJ/hr (4,020 BTU/hr)

10-slot: 1,411 KJ/hr (1,340 BTU/hr)

Front to back

30.3 cm (1 ft)

60.6 cm (2 ft)

Hardware Data Sheets 6-11

6


Cabinets for Rackmount Enclosures

Pre-wired 19-inch-wide cabinets, ready for installation, are available in the following dimensions to accept rackmount storage systems.

Vertical space

173 cm or 68.25 in

(39 NEMA units or

U; one U is 1.75 in)

Exterior dimensions Comments

Height: 192 cm (75.3 in)

Width: 65 cm (25.5 in)

Depth: 87 cm (34.25 in) plus service clearances, which are 90 cm (3 ft),

30 cm (1.1 ft) front and 60 cm (2.3 ft) back

Accepts combinations of:

DPEs at 6.5 U,

SPS units at 1 U,

DAEs at 3.5 U each,

Switches at 2 U (16-port) or 1 U (8-port)

Weight (empty): 134 kg (296 lb)

Requires 200–240 volts ac. Single-phase plug options include L6–30 or L7–30

(domestic) and IEC 309 30 A

(international).

Dual power strips are available. Each power strip has 12 IEC-320 C19 outlets.

Filler panels of various sizes are available.

As an example, a rackmount storage system that supports 100 disk modules has the following requirements.

Category

Vertical cabinet space in

NEMA units (U, one U is

1.75 in)

Weight

Power

Cooling

Requirement

Bottom to top: One SPS (1 U), one DPE (6.5 U), and nine DAEs (9*3.5 U equals 31.5 U) for a total of 39 U.

519 kg (1,142 lb) including the cabinet (134 kg), DPE (55 kg), SPS (11 kg), and nine DAEs (9 * 35.4 kg equals 319 kg).

4,500 VA max, including the DPE (800 VA), SPS (100 VA), and nine DAEs

(9 * 400 VA equals 3600 VA).

15,700 KJ/hour (14,884 BTU/hr), including the DPE (2,736

KJ/hr), SPS (265 KJ/hour, estimated), and nine DAEs (9*1,411 KJ/hr equals

12,699 KJ/hr).



6

Cable and Configuration Guidelines

Table 6-1

FC4700-series storage systems require optical cable between servers, switches, and SPs. The cabling between DPE and DAE enclosures

(1 m, 3.3 feet) is copper.

You can use any existing FDDI, multimode, 62.5-micron cable with good connections to attach servers, switches, and storage systems.

These cables must be dedicated to storage-system I/O.

Cable Types and Sizes

Length

5 m (16.5 ft) or

10 m (33 ft) optical


Typical use

Within one room, connecting servers to storage systems

(adapter must support optical cable) or connecting switches to storage systems

Within one building, connecting servers to storage systems



250 m (821 ft,.15 mi) optical

500 m (1642 ft,.31 mi) optical

1 m (3.3 ft) copper

Within one complex, connecting servers to storage systems


Within one cabinet, connects the DPE to a DAE

.5 m (1.7 ft) copper Within one cabinet, connects DAEs to DAEs

Optical cabling is 50 micron (maximum length is 500 m (1,650 ft) or 62.5 micron (maximum length is 300 m (985 ft). The minimum bend radius is 3 cm (1.2 in).

Component planning diagrams and worksheets follow.

Hardware Planning Worksheets

Following are worksheets to note hardware components you want.

Some installation types do not have switches or multiple servers.

Cable and Configuration Guidelines 6-13

6


Cable Planning Template

Server 1 Server 2

F2

D1

F2

A1

A1

Switch 1

DAE

An

An

Switch 2

DAE

F2

F2

D1

DAE

F1 F1

DPE

SP B SP A

Storage system

DAE

Dm Dm

F2 F2

DAE

F2 F2

DAE

F1 F1

Path 1

Path 2

DPE

SP B SP A

Figure 6-6 Cable Planning Template — FC4700 Shared Storage System

Storage system

EMC1833



6

The cable identifiers apply to all storage systems

Hardware Component Worksheet

Number of servers:____ Adapters in servers:____ Switches: 16-port:____8-port:____

Rackmount DPEs:_____SP/LCC pairs:_____PSs:_____SPSs:____ Rackmount cabinets:___

Rackmount DAEs:_____ ................................LCCs:_____PSs:_____

Cables between server and switch - Cable A

Cable A

1,

Optical: Number:____ ....................................................... ............. Length________m or ft

Cable A

2,

Optical: Number:____ ....................................................... ............. Length________m or ft

Cable A n

,Optical: Number:____ ........................................................ ............. Length________m or ft

Cables between switches and storage systems - Cable D

Cable D

1,

One or Two per SP, Optical:Number:_____ ...................... ............. Length________m or ft

Cable D

2,


Cable D m,

One or Two per SP, Optical:Number:_____ ..................... ............. Length________m or ft

Cables between enclosures

Cable F

1

(Copper, 1.0 m): Number (2 per storage system): ______

Cable F

2

:(Copper, 0.5 m): Number (2 per DAE): ______

Hardware Planning Worksheets 6-15

6


Sample Cable Templates



Database Server

Switch 1

A2

Cable between server and switch

Switch 2

DAE

DAE

Cable between switch and storage system

D1

F2

Path 1

Path 2

DAE

DAE

F2

F1

DAE

DPE

SP B SP A

F2

F2

F1

Cable between storage systems or enclosures

EMC1834

Figure 6-7 Sample Shared Storage Installation



6

Hardware Component Worksheet

Servers:__ 3 _ Adapters in servers:__ 6 _ Switches: 16-port:____8-port:__ 2 __

Rackmount DPEs:__ 1 ___SP/LCC pairs:__ 2 ___PSs:___ 2 __SPSs:__ 2 __ Rackmount cabinets:_ 1 __

Rackmount DAEs:__ 6 ___............................. LCCs:___ 12 __PSs:___ 12 __

Cables between server and switch - Cable A

Cable A

1,

Optical: Number:__ 2 __ .................................................... ............. Length____ 33 _ m or ft

Cable A

2,

Optical: Number:__ 4 __ ..................................................... ............. Length__ 1628 _m or ft

Cable A n

,Optical: Number:_____ ...................................................... ............. Length________m or ft

Cables between switches and storage systems - Cable D

Cable D

1,

One or Two per SP, Optical:Number:__ 2 ___ .................... ............. Length___ 33 ___m or ft

Cable D

2,

One or Two per SP, Optical:Number:_____ ....................... ............. Length________m or ft

Cable D m,


Cables between enclosures

Cable F

1

(Copper, 1.0 m): Number (2 per storage system):: ___ 12 _

Cable F

2

:(Copper, 0.5 m): Number (2 per DAE): ____ 2 __

What Next?

This chapter explained hardware components of storage systems. If you have completed the worksheets to your satisfaction, you are ready to consider ordering some of this equipment. Or you may want to read about storage management in the next chapter.

Hardware Planning Worksheets 6-17

6



Invisible Body Tag

7

Storage-System

Management

This chapter explains the applications you can use to manage storage systems from servers. Topics are

• Using Navisphere Manager Software .............................................7-3

• Storage Management Worksheet .....................................................7-4

Storage-System Management 7-1

7

Storage-System Management

Introducing Navisphere Management Software

Navisphere software lets you bind and unbind disks, manipulate caches, examine storage-system status and logged events, transfer control from one SP to another, and examine events recorded in storage-system event logs.

Navisphere products have two parts: a graphical user interface (GUI) and an Agent. The GUIs run on a management station, accessible from a common framework, and communicate with storage systems through a single Agent application that runs on each server. The

Navisphere products are

• Navisphere Manager, which lets you manage multiple storage systems on multiple servers simultaneously.

• Navisphere Analyzer, which lets you measure, compare, and chart the performance of SPs, LUNs, and disks.

• Navisphere Integrator, which provides an interface between

Navisphere products and HP OpenView, CA Unicenter, and

Tivoli.

• Navisphere Event Monitor, which checks storage systems for fault conditions and can notify you and/or customer service if any fault condition occurs.

• Navisphere failover software. Application Transparent Failover

(ATF) is an optional software package for high-availability installations. ATF software lets applications continue running after the failure anywhere in the path to a LUN: a host bus adapter, cable, switch, or SP. ATF is required for any server that has two host bus adapters connected to the same storage system.

Another failover product is CDE (Driver Extensions) software, which has limited failover features. CDE is included with each host bus adapter driver package.

• Navisphere Agent, which is included with each storage system, and Navisphere CLI (Command Line Interface), which lets you bypass the GUI and type commands directly to storage systems.

The Agent runs on any of several different platforms, including

Windows and popular UNIX platforms; the other products run on

Windows platforms only.



7

Using Navisphere Manager Software

Navisphere Manager software (Manager) lets you manage multiple storage systems connected to servers on a TCP/IP network. Manager offers extensive management features and includes comprehensive on-line help.

Manager runs on a management station, which is a Windows NT

®

or

Windows

®

2000 server. The servers connected to a storage system can run Windows 2000, Windows NT, or a UNIX operating system such as Sun Solaris. Servers connected to the SAN can run different operating systems.

The following figure shows Navisphere Manager in a shared switched environment.

File Server Management

Station and Server

Operating system A

Navisphere

Manager

Navisphere

Agent

Failover software

Mail Server Management

Station and Server

Operating system A

Navisphere

Manager

Database Server Production Server

Operating system B

Operating system C

Navisphere

Agent

Navisphere

Agent

Navisphere

Agent

Failover software

Failover software

Failover software

LAN


Path 1

Path 2

LAN (storage-system management)

EMC1835

Figure 7-1 Sample Shared Switched Environment with Manager

Using Navisphere Manager Software 7-3

7


Storage Management Worksheet

The following worksheet will help you plan your storage-system management environment. For each server, complete a section.

For anyone to manage a storage system connected to a server, that person’s username and hostname must be identified as privileged though Navisphere management software.

On the worksheet, complete the management station server hostname and operating system; then decide whether you want the

Navisphere Analyzer and/or Event Monitor and, if so, mark the appropriate boxes. Then write the name of each managed server, with operating system, Storage Group, and manager user@host names.

You can copy much of the needed information from the LUN and

Storage Group planning worksheet in Chapter 5.

The Storage Group feature is provided by EMC Access Logix software.

Access Logix is required for all shared installations (shared switched or shared direct), but optional for unshared direct installations. If you don’t need Storage Groups and Access Logix, then on the LUN and Storage Group worksheet, skip the Storage Group entries.



7

Management Utility Worksheet – Shared Storage with FC4700

Management station hostname:___________________Operating system:_______________

Software: ❑ Navisphere Manager/Agent ❑ Navisphere Analyzer ❑ Navisphere Event Monitor

List all the servers this host will manage. Each server whose storage system is a managed server must run Navisphere Agent and ATF software of the same type as its operating system. ATF is optional with unshared storage.

Server: Op sys: Storage Group no./name: Manager user@host:








Management station hostname:___________________Operating system:_______________

Software: ❑ Navisphere Manager/Agent ❑ Navisphere Analyzer ❑ Navisphere Event Monitor

List all the servers this host will manage. Each server whose storage system is a managed server must run Navisphere Agent and ATF software of the same type as its operating system. ATF is optional with unshared storage.









Storage Management Worksheet 7-5

7



Index

A ac power requirements

DAE 6-10

DPE 6-9

storage system 6-12

Access Logix option 1-9

adapter driver package 1-4

ALPA ID 5-16

application

planning 5-8

sample, for RAID groups 2-19

worksheet 5-8

Application Transparent Failover (ATF) software

7-2

array, see also disk-array storage system

audience for manual 2-ix

B

back-end bus 6-5

Base Software 6-5 bus, back-end 6-5

C

cabinets for rackmount storage systems 6-12

cabling

guidelines 6-13 types and sizes 6-13

cache

snapshot 4-2

storage system 6-6

storage system, size 5-16 cache size 5-16

cascading switches

CDE driver extensions software 7-2

chunk (snapshot) size 4-5

CLI (Command Line Interface) 7-2

components, storage system 6-3

configurations

LUN and file system, planning 5-8

RAID, planning 5-8

see also installation types

cooling requirements

cabinet with enclosures 6-12

DAE 6-11

DPE 6-10

Core Software, see Base Software

cross mirroring 3-4

CRUs (customer replaceable units) 6-3

D

DAE (Disk Array Enclosure) 6-3

dimensions 6-11 site requirements 6-11

data sheets

hardware 6-9, 6-11

device name, operating system 5-19

disaster recovery (MirrorView) 3-2

disk

LUNs, planning 5-8

mirror, defined 2-2

module IDs 5-5

RAID types

compared 2-12

guidelines 2-17

shared storage systems, examples 5-3

EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide i-1

Index i-2

striping, defined 2-2

unit number on worksheet 5-10, 5-17

disk-array storage system

application and LUN planning worksheet

5-8

cabinets 6-12

components 6-3

dimensions 6-9

hardware 1-13

hardware requirements shared/unshared

6-8

installation types 1-8

managing 7-3

power requirements 6-12

remote mirror example 3-7

sample shared installation 5-3

site requirments 6-12

SP 6-5

unshared 5-7

weight 6-12

DPE (Disk Array Processor Enclosure)

components 6-3

dimensions 6-9 site requirements 6-9 weight 6-9

driver extensions software (CDE) 7-2

dual paths to LUNs 5-2

E

enclosure address (EA) 6-4

F

fabric, switch, introduced 1-3

failure with remote mirror 3-5, 3-6

fan-in (switch) 1-6 fan-out (switch) 1-6

Fibre Channel

adapter 1-4 components 1-4

defined 1-3

switch

description, see also switch switch, description 1-5

file system

name 5-19

planning 5-8

EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide footprint

cabinet 6-12

DPE 6-9

storage system 6-12

fracture (mirror) 3-6

front-end port 6-5

G

GBIC (gigabit interface converter) 3-3

global spare, see also hot spare

GUI (in storage-system management utilities) 7-3

H hardware

data sheets 6-9

mirroring 2-2 mirroring, see also MirrorView software

planning worksheets 6-13

storage 6-3

storage system 1-13

tradeoffs 6-8

heat dissipation

DPE 6-9

storage system 6-10

height

DAE 6-11

DPE 6-9

storage system 6-12

high availability

hardware tradeoffs 6-8

remote mirror 3-4

shared switched installation 1-8

host, see server

host-bus adapter (HBA) 1-4 host-bus adapter driver package 1-4

hot spare

defined 2-9

sample applications 2-20

when to use 2-18

I image (mirror)

defined 2-2

image (remote mirror), defined 3-2

individual access array, see RAID 5 Group

Index individual disk unit

defined 2-9

performance 2-14


when to use 2-18

installation

LUN and file system

planning 5-8

sample 5-3

types 1-8

sample unshared direct 5-7

sample, shared switched 5-3

interconnect components, cables, hubs, switches

1-4

interface kit, see host bus adapter driver package

IP address of SP 5-16

L

logical volume 5-9

logical volume, see also file system

LUN (logical unit)

configurations, planning 5-8

disk mirror, defined 2-2

hot spare 2-9

in RAID Group 2-3

individual disk 2-9

number on worksheet 5-10, 5-17

paths to 5-2

planning file systems 5-8

RAID 0 Group 2-7

RAID 1 mirrored pair 2-7

RAID 1/0 Group 2-8

RAID 5 Group 2-4

RAID types

compared 2-5, 2-12

see also Chapter 2

shared storage

examples 5-3

unshared storage

example 5-7

worksheet 5-14

M memory, SP

specifying on worksheet 5-16

mirrored pair, see RAID 1 mirrored pair mirrored RAID 0 Group, see RAID 1/0 Group

mirroring, defined 2-2 mirroring, remote, see also MirroView or remote mirroring

MirrorView software

about 3-2

benefits 3-4

example 3-7

see Chapter 3

multipath I/O 1-8

N

Navisphere Manager utility 7-2

Navisphere product set 7-3

node, defined 1-3

nonredundant array, see RAID 0 Group

O operating system

device name for disk unit 5-19

software mirroring 2-2

optical cable, types and sizes 6-13

P

page size, storage system cache 5-16

parallel access array, see RAID 3 Group

paths to LUNs 5-2

performance, RAID Group 2-13

physical disk unit, see LUN (logical unit) physical volume, see LUN (logical unit)

planning

LUNs and file systems 5-8

See also worksheets

plug types 6-12

port 6-5

SP ALPA ID 5-16

power requirements

DAE 6-11

DPE 6-9

primary image

defined 3-2

failure 3-5

production host (SnapView) 3-2, 4-2

promotion of secondary image 3-6, 3-8


Index i-4

R

rackmount storage system hardware components

6-3

RAID 0 Group

defined 2-7


when to use 2-18

RAID 1 mirrored pair

defined 2-7


when to use 2-17

RAID 1/0 Group

defined 2-8


when to use 2-17

RAID 3 Group

defined 2-5


when to use 2-17

RAID 5 Group

defined 2-4


when to use 2-17

RAID Group

application guidelines 2-19

performance tradeoffs 2-13

planning worksheet 5-8


shared storage examples 5-3

type guidelines 2-17

types, compared 2-12

RAID Groups and LUNs 2-3

read cache 6-6

redundant array of independent disks (RAID), see

RAID Group

remote mirroring

example 3-7

promotion 3-8

See also Chapter 3

S secondary image

defined 3-2

failure 3-6

promotion 3-6, 3-8

server

cabling guidelines 6-13

connection to storage system 1-3 connection to storage system, see also cabling

service clearance

DAE 6-11

DPE 6-10

shared storage systems

application and LUN planning 5-8

components 6-8

examples 5-3

hardware planning worksheets 6-13

requirements 6-8

shared-or-clustered direct installation type

defined 1-8

shared switched installation type

defined 1-8

sample 5-3

site requirements

DAE 6-11

DPE 6-9

storage systems 6-12

size

cache 5-16

chunk 4-5

SnapView snapshot software

about 4-2

benefits 4-3

cache 4-2 components 4-2 snapshot 4-2

software mirroring 2-2

SP (storage processor)

about 6-5

cache size 5-16

in remote mirror 3-4

IP address 5-16 port ALPA ID 5-16

software 6-5

storage

managment worksheets 7-4

system components 6-3

types

defined 1-8

see also disk-array storage system, installation types

stripe

disk, defined 2-2


RAID 3 Group 2-5

with RAID 1/0, RAID 0 2-8

with RAID 5 2-4

switch

cascading description

fabric, introduced 1-3 introduced 1-3

sample shared storage installation 5-3

zone 1-6

T temperature requirements

DPE 6-9

storage system 6-10, 6-11

tradeoffs

hardware, shared storage 6-8

RAID types 2-12

U

unshared direct installation type, sample 5-7

unshared storage systems

application and LUN planning 5-8

components 6-8

defined 1-8

hardware planning worksheets 6-13

requirements 6-8

sample 5-7

V

vault disks 2-10

volume name 5-19

W weight

DAE 6-11

DPE 6-9

storage system 6-12

worksheet

application 5-8

hardware 6-13

LUN 5-14

LUN configuration 5-15

storage management 7-4, 7-5

write cache 6-6

write intent log (remote mirror) 3-5

Z

zone, switch 1-6

Index


Index i-6 EMC Fibre Channel Storage System Model FC4700 Configuration Planning Guide

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