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Chapter 1.

Logical partitioning primer

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This chapter introduces the concepts and terminology that are necessary to understand the logical partitioning implementation on the IBM

Sserver

p5 and

OpenPower servers. It discusses the following topics:

1.1, “An introduction to partitioning” on page 2

1.2, “Introduction to Micro-Partitioning and Virtualization” on page 4

1.3, “Partitioning on eServer p5 and OpenPower servers” on page 10

1.4, “IBM Hardware Management Console” on page 11

1.5, “IBM ^ Information Center” on page 14

1.6, “LPAR Validation Tool” on page 15

1.7, “Operating system support” on page 16

If you are a system administrator who has responsibility for managing partitioning-capable pSeries servers, it is imperative that you become familiar with the aspects described in this chapter before you run the system in a logical partitioned environment.

© Copyright IBM Corp. 2003, 2004. All rights reserved.

1

1.1 An introduction to partitioning

There is a strong demand for high-end systems that can provide greater flexibility. In particular, system administrators want the ability to subdivide high-end systems into smaller partitions that are capable of running a version of an operating system or a specific set of application workloads.

IBM initially started work on partitioning in S/370™ mainframe systems in the

1970s. Since then, logical partitioning (LPAR) on IBM mainframes (now called

IBM

^

zSeries®) has evolved from a predominantly physical partitioning scheme, based on hardware boundaries, to one that allows for virtual and shared resources with dynamic load balancing. In 1999, IBM implemented LPAR support on the AS/400® platform (now called iSeries™). In 2000, IBM announced the ability to run the Linux operating system in an LPAR on a zSeries server, followed by the pSeries and iSeries platforms.

Continuing the evolution of partitioning technology on pSeries servers, the

IBM

^

p5 and OpenPower extends its capabilities by further improving flexibility in partition usage. There are now two types of partitions in the

IBM

^

p5 and OpenPower. Partitions can have dedicated processors, or they can have virtualized processors from a single pool of shared physical processors. Sharing a pool of virtualized processors is known as

Micro-Partitioning technology

. Both types of partitions can coexist at the same time in the same system.

Ethernet and SCSI I/O devices also have been virtualized enabling these resources to be shared by multiple partitions. The advantages of this technology include allocations of smaller resource units, more partitions, and higher, more efficient resource utilization.

IBM

^

p5 and OpenPower systems have the ability to use Virtual

Ethernet and Virtual SCSI, although they can use the physical resources, if desired, or a mix of the two.

For more information about virtualization of resources, refer to Chapter 4,

“Virtualized resource management” on page 83.

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1.1.1 Basic types of partitioning

This publication refers to various partitioning mechanisms. The following are some terms and definitions that this book uses:

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Building block

A collection of system resources, such as CPUs, memory, and I/O connections. These may be physically packaged as a self-contained symmetric multiprocessing (SMP) system (rack-mounted or desk-side) or as boards within a larger multiprocessor system. There is no requirement for the

CPUs, memory, and I/O slots to occupy the same physical board within the system, although they often do.

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Physical partition

One or more building blocks linked together by a high-speed interconnect.

Generally, the interconnect is used to form a single, coherent memory address space. In a system that is only capable of physical partitioning, a partition is a group of one or more building blocks that is configured to support an operating system image. Other vendors may refer to physical partitions as

domains

or

nPartitions

. The maximum number of physical processors in a

POWER5™ system at the time of the writing of this book is 64.

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Logical partition

A subset of logical resources that are capable of supporting an operating system. A logical partition consists of CPUs, memory, and I/O slots that are a subset of the pool of available resources within a system.

Dedicated processor partition

A logical partition whose CPU resources are dedicated to the LPAR along with the memory and I/O slots. CPU idle time cannot be used by other LPARs.

Shared processor partition

Using Micro-Partitioning technology, physical processors are divided into virtual processors that are shared in a pool between one or more LPARs. The

LPARs using the shared pool can be a mix of operating systems.

Note: The major difference between partitioning types is the granularity and

flexibility that is available for allocating resources to an operating system image. Logical partitions have finer granularities than physical partitions, while

Micro-Partitioning technology allows for even smaller allocations of resources.

1.1.2 Partition isolation and security

From a functional point of view, applications run inside partitions in the same way that they run on a stand-alone

Sserver

p5 and OpenPower server. There are no

Chapter 1. Logical partitioning primer

3

issues when moving an application from a stand-alone server to a partition. The design of a partitioning-capable server is such that one partition is isolated from software that is running in the other partitions, including protection against natural software defects and even deliberate software attempts to break the partition barriers. It has the following security features:

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Protection against inter-partition data access

The design of partitioning-capable

Sserver

p5 and OpenPower servers prevents any data access between partitions, other than using shared networks. This design isolates the partitions against unauthorized access across partition boundaries.

Unexpected partition crash

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A software failure within a partition should not cause any disruption to the other partitions. Neither an application failure nor an operating system failure inside a partition interferes with the operation of other partitions.

Denial of service across shared resources

The design of partitioning-capable

Sserver

p5 and OpenPower servers prevents partitions from making extensive use of a shared resource so that other partitions using that resource become starved. This design means that partitions sharing the same peripheral component interconnect (PCI) bridge chips, for example, cannot occupy the bus indefinitely.

With partition isolation and security, you can consolidate applications safely within partitions in partitioning-capable

Sserver

p5 and OpenPower servers without compromising overall system security.

1.2 Introduction to Micro-Partitioning and Virtualization

The following sections introduce the basic concepts of Micro-Partitioning as well as the Virtualization capabilities of the

Sserver

p5 and OpenPower servers. You can find a more detailed discussion about using

Sserver

p5 servers and AIX 5L

Version 5.3 in Chapter 4, “Virtualized resource management” on page 83.

1.2.1 Micro-Partitioning

The Micro-Partitioning model offers a virtualization of system resources. In

POWER5 processor-based systems, physical resources are abstracted into virtual resources that are available to partitions. This sharing method is the primary feature of this new partitioning concept, and it happens transparently.

POWER5 Micro-Partitioning technology specifies processor capacity in processing units. One processing unit represents 1% of one physical processor.

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1.0 represents the power of one processor. A partition defined with 220 processing units is equivalent to the power of 2.2 physical processors. Creating a partition using Micro-Partitioning technology, the minimum capacity is 10 processing units, or 1/10 of a physical processor. A maximum of 10 partitions for each physical processor may be defined, but on a loaded system the practical limit is less. The practical limit to the number of partitions is based on available hardware and performance objectives.

Micro-Partitions can also be defined with capped and uncapped attributes. A capped Micro-Partition is not allowed to exceed the defined capacity. A configuration flag inside the Hardware Management Console (HMC) menus determines whether the capacity is capped. An uncapped partition, however, is allowed to consume additional capacity with fewer restrictions. Uncapped partitions can be configured to the total idle capacity of the server or to a percentage of the total idle capacity.

1.2.2 Virtual Ethernet

Virtual Ethernet enables inter-partition communications without a dedicated physical network adapter. With this feature, you can define in-memory point-to-point connection between partitions. These connections have the same characteristics as a high-bandwidth Ethernet network and support multiple networking protocols, such as IPv4, IPv6, and ICMP.

1.2.3 Virtual I/O Server

The Virtual I/O Server is a special-purpose partition that provides virtual I/O resources to client partitions. The Virtual I/O Server owns the real resources that are shared with other clients. With Virtual I/O technology, you can assign a physical adapter to a partition to be shared by one or more partitions, enabling clients to minimize their number of physical adapters. You can use the Virtual I/O

Server to reduce costs by eliminating the requirement that each partition has a dedicated network adapter, disk adapter, and disk drive.

To ensure stable performance, it is preferable to use the Virtual I/O server in a partition with dedicated resources.

The following sections discuss the two major functions that the Virtual I/O Server provides.

Shared Ethernet Adapter

A Shared Ethernet Adapter (SEA) is a new service that acts as a Layer 2 network switch to route network traffic from a Virtual Ethernet to a real network adapter.

The SEA must run in a Virtual I/O Server partition.

Chapter 1. Logical partitioning primer

5

The advantage of the SEA is that partitions can communicate outside the system without having a physical network adapter attached to the partition. Up to 18

VLANs can be shared on a single network interface. The amount of network traffic will limit the number of client partitions that are served through a single network interface.

Virtual SCSI

Access to real storage devices is implemented through the Virtual SCSI services, a part of the Virtual I/O Server partition. Logical volumes that are created and exported on the Virtual I/O Server partition are shown at the virtual storage client partition as a SCSI disk. All current storage device types such as SAN, SCSI, and RAID are supported.

The Virtual I/O server supports logical mirroring and RAID configurations. Logical volumes created on RAID or JBOD configurations are bootable, and the number of logical volumes is limited to the amount of storage available and architectural limits of the Logical Volume Manager (LVM).

Resources removed from a partition are marked as free (free resources) and are owned by the global firmware of system. You can consider these resources as kept in the free resource pool. You can add free resources to any partition in a system as long as the system has enough free resources.

Note: The Shared Ethernet Adapter and Virtual SCSI server functions are

provided in the Virtual I/O Server that is included in the Advanced POWER

Virtualization feature, an additional feature of

Sserver

p5 systems.

1.2.4 Advanced POWER Virtualization technologies

This section provides information about the packaging information for the

Advanced POWER Virtualization feature available on

Sserver

p5 systems. A

more detailed description, including configuration, is provided in Chapter 4,

“Virtualized resource management” on page 83.

This feature is a combination of the hardware capability inherent in POWER5 servers and the following components, available together as a single-priced feature:

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Firmware enablement for Micro-Partitioning technology

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Installation image for the Virtual I/O Server software which supports:

– SEA

– Virtual SCSI

Partition Load Manager

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Note: Virtual Ethernet and partitioning are available without this feature when

the server is attached to an HMC.

Simultaneous Multi Threading (SMT) is available on the base hardware and

requires no additional features. See 2.1.1, “Hardware” on page 26 for a

discussion about SMT.

Figure 1-1 shows a detailed overview of the different parts of the hardware order

that enable firmware and that include the software orders.

HW Order

Advanced POW ER Virtualization Feature

KEY

CD in box

CD in box

Micro-Partitioning

Key enables both Micro-partitioning and Virtual IO-Server

Virtual I/O-Server (VIO)

(I/O Appliance, VLAN & Virtual SCSI Server)

Virtual I/O-Server Software Maintenance

Partition Load Manger (PLM)

PLM Software Maintenance

HW FC

Firmware

SW

Figure 1-1 Advanced POWER Virtualization feature

1.2.5 Advanced OpenPower Virtualization technologies

The Advanced OpenPower Virtualization technologies are available on

IBM

^

OpenPower systems. The Advanced OpenPower Virtualization technologies are a combination of hardware and software features that include the following components and are available as separately priced options:

򐂰 Firmware enablement for the POWER Hypervisor™, which supports:

– LPAR

– Dynamic logical partitioning

– Micro-Partitioning

Chapter 1. Logical partitioning primer

7

򐂰 Installation image for the Virtual I/O Server software, which supports:

– SEA

– Virtual SCSI server

When you order the hardware feature directly from an IBM marketing representative and specify with the initial system order, the shipped firmware is activated to support Micro-Partitioning and the Virtual I/O Server. For upgrades, or any orders placed through IBM Business Partners, customers and IBM

Business Partners must follow the instructions included in the option kit to receive an activation code that will enable the firmware.

These two technology offerings are ordered separately. While the Virtual I/O

Server is not required for the POWER Hypervisor to operate, the POWER

Hypervisor must be installed for Virtual I/O Server to function. While not required, we highly recommend the Virtual I/O Server for use with the POWER Hypervisor technology. It facilitates the sharing of physical I/O resources between logical partitions and can significantly increase system use and capability.

You can find additional information about Advanced OpenPower Virtualization technologies at: http://www.ibm.com/servers/eserver/linux/power/features/virtualization.html

1.2.6 Obtaining the Virtual I/O Server and Partition Load Manager

Virtual I/O Server and Partition Load Manager (PLM) are licensed software components of the Advanced POWER Virtualization feature. They contain one charge unit per installed processor, including software maintenance. The initial software license charge for Virtual I/O Server and PLM is included in the price of the Advanced POWER Virtualization feature.

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The related hardware features that include Virtual I/O Server and PLM are:

9110-510 (FC 7432)

9111-520 (FC 7940)

9113-550 (FC 7941)

9117-570 (FC 7942)

9119-590 (FC 7992)

9119-595 (FC 7992)

9123-710 (FC 1965)

9124-720 (FC 1965)

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For each Virtual I/O Server license ordered, an order for one of the following software maintenance agreement (SWMA) is also required:

One-year (5771-VIO)

Three-year (5773-VIO)

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The processor-based license enables you to install multiple Virtual I/O Server partitions on a single server to provide redundancy and to spread the Virtual I/O

Server workload across multiple partitions.

Virtual I/O Server

The Virtual I/O Server resides in a POWER5 partition as a single-function appliance, which is created using the HMC. The Virtual I/O Server installation media ships with a POWER5 system configured with the Advanced POWER

Virtualization feature. It supports network install (NIMOL from HMC) or CD installation, AIX 5L Version 5.3, SUSE LINUX Enterprise Server 9 for POWER, and Red Hat Enterprise Linux AS for POWER Version 3 as Virtual I/O clients.

The Virtual I/O Server provides the Virtual SCSI server and Shared Ethernet

Adapter virtual I/O function to client Linux or AIX partitions. This

Sserver

p5 partition is not intended to run applications or for general user login.

Partition Load Manager

With PLM for AIX 5L, you can maximize the use of processor and memory resources on POWER5 servers that support dynamic logical partitioning. Within the constraints of a user-defined policy, resources are automatically moved to partitions with a high demand from partitions with a lower demand. Thus, you can fully use resources that would otherwise go unused.

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PLM supports management of any dynamic LPAR that is running the following:

AIX 5L Version 5.2 ML5200-04

AIX 5L Version 5.3 or later

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Features available in PLM are:

Automated processor and memory reconfiguration

Real-time partition configuration and load statistics

Support for dedicated and shared processor partition groups

Support for manual provisioning of resources

Graphical user interface (Web-based System Manager)

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For each Partition Load Manager V1.1 (5765-G31) license that you order, you must also order one of the following SWMAs:

One-year (5771-PLM)

Three-year (5773-PLM)

Software maintenance for PLM is priced on a per-processor basis, by processor

group. Refer to 3.4, “Partition Load Manager” on page 71 for more detailed

information about PLM.

Chapter 1. Logical partitioning primer

9

1.3 Partitioning on eServer p5 and OpenPower servers

Table 1-1 provides the

Sserver

p5 and OpenPower server product range available at the time of the writing of this book.

Table 1-1 eServer p5 and OpenPower servers

Official product model name Short product name

IBM

Sserver

p5 Model 510

IBM

Sserver

p5 Model 520

IBM

Sserver p5 Model 550

IBM

Sserver p5 Model 570

IBM

Sserver p5 Model 590

IBM

Sserver p5 Model 595

IBM

Sserver

OpenPower 710

IBM

Sserver

OpenPower 720 p5-510 p5-520 p5-550 p5-570 p5-590 p5-595

OpenPower 710

OpenPower 720

M/T-MDL

9110-510

9111-520

9113-550

9117-570

9119-590

9119-595

9123-710

9124-720

Note: Hereafter, this book uses the short product names.

Micro-Partitioning is supported across the entire POWER5 product line, from the

entry to the high-end systems. Table 1-2 shows the maximum number of logical

partitions and shared processor partitions that the different models support

(provided that enough boot devices are available).

Table 1-2 Maximum number of processors, memory size, and partitions

Short product name

Max number of processors

Max

Memory size

Max number of I/O drawers

Dedicated processor partitions

Shared processor partitions

p5-510 2 32 GB 0 2 20 p5-520 p5-550 p5-570 p5-590 p5-595

2

4

16

32

64

32 GB

64 GB

512 GB

1 TB

2 TB

4

8

20

7

11

2

4

16

32

64

20

40

160

254

254

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Short product name

OpenPower 710

OpenPower 720

2

4

Max number of processors

Max

Memory size

Max number of I/O drawers

32 GB

64 GB

0

2

Dedicated processor partitions

Shared processor partitions

12

4

20

40

The maximums stated in Table 1-2 are supported by the hardware. However, the

practical limits based on production workloads can be significantly lower.

The logical partitioning concept and required tasks are basically similar on these partitioning-capable

Sserver

p5 and OpenPower server models. However, assigning I/O resources to partitions depends on the models, and there are significant differences. For the hardware model-specific information about the I/O

resource assignments, see 2.4, “I/O device assignment considerations” on page 46.

1.4 IBM Hardware Management Console

To configure and manage logical partitions on a

Sserver

p5 and OpenPower server, you must have at least one Hardware Management Console (HMC). For

more information about the HMC, refer to 3.1, “Hardware Management Console” on page 58.

Depending on the partitioning-capable server models, you can order the HMC as

a feature code or a separate orderable product, as shown in Table 1-3 on page 12. The 7310 is for POWER5-based systems, and the 7315 is for

POWER4™-based systems.

Chapter 1. Logical partitioning primer

11

Table 1-3 Required Hardware Management Console

Short Product Name HMC

p5-595 p5-590

7310-C04 or 7310-CR3

7310-C04 or 7310-CR3 p5-570 p5-550 p5-520 p5-510

7310-C04 or 7310-CR3

7310-C04 or 7310-CR3

7310-C04 or 7310-CR3

7310-C04 or 7310-CR3

Note

1

1

2

2

2

2

OpenPower 720

OpenPower 710

7310-C04 or 7310-CR3

7310-C04 or 7310-CR3

2

2

1. An HMC is required.

2. An HMC is required if the system is partitioned. The HMC is not required if the system is running as a full system partition.

The HMC provides a set of functions that is necessary to manage the systems.

The functions are LPAR, dynamic LPAR (DLPAR), Capacity on Demand without reboot, inventory and microcode management, and remote power control functions.

The HMC is a dedicated computer that provides a graphical user interface for configuring and operating servers that are functioning either in non-partitioned or in a full system partition. It is configured with a set of hardware management applications for configuring and partitioning the server. One HMC is capable of controlling multiple servers. At the time of the writing of this book, a maximum of

32 non-clustered servers and a maximum of 254 partitions are supported by one

HMC. You can also add a second HMC for redundancy (see Figure 1-2 on page 13).

Note: It is not possible to connect POWER4 and POWER5 processor-based

systems to the same HMC simultaneously.

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Figure 1-2 HMC connection

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The HMC provides a set of functions that are necessary to manage partition configurations by communicating with the service processor, as follows:

򐂰 LPR control

Capacity on Demand resource control

Creation or partition and system profiles

Boot, start, and stop actions for the system or individual partitions

Displaying system and partition status

In a non-partitionable system, the operator panel displays the LED codes. In a partitioned system, the operator panel shows the word

LPAR

instead of any partition LED codes. Therefore, all LED codes for system partitions are displayed over the HMC.

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An imbedded DVD-RAM for creating and storing configuration backup information

Cluster support when combined with IBM Cluster Systems Management V1.4 or later

Using a virtual console for each partition or controlled system

With this feature, you can access every partition over the trusted network

HMC connection to the server. This is a convenient feature when the partition is not reachable across the public network.

Chapter 1. Logical partitioning primer

13

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The HMC provides a Service Focal Point for the systems it controls. It is connected to the service processor of the system using network connection and must be connected to each partition using an Ethernet LAN for Service

Focal Point and to coordinate dynamic logical partitioning operations.

The HMC provides tools for problem determination and service support, such as call-home and error log notification through an analog phone line or

Ethernet.

Note: A partitioning-capable pSeries server that is managed by HMC is also

referred to as a managed system.

1.5 IBM

^

Information Center

The IBM

^

Information Center provides a source of technical information about IBM

^

p5 hardware. It offers technical documentation about how to configure and optimize

Sserver

p5 and OpenPower servers.

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With AIX 5L Version 5.3, the role of the IBM

^

and AIX Information Center has been expanded to provide a standardized and central repository for all relevant AIX and pSeries (prior to

Sserver

p5) manuals and documentation.

The two components which make up the AIX InfoCenter structure are the existing

InfoCenter Web portal and the AIX documentation CD. Both of these sources contain the following:

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A message database that shows the meaning of error messages and, in many cases, how to recover from the error. This database also provides information for LED codes and error identifiers.

򐂰 How-to tips with step-by-step instructions for completing system administrator and user tasks.

FAQs for quick answers to common questions.

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The entire AIX software documentation library for Version 5.1, Version 5.2, and Version 5.3. Each publication is available in PDF format, and abstracts are provided for books for Version 5.2 and Version 5.3.

Links to related documentation from IBM, including white papers, IBM

Redbooks, and technical reports on topics such as RS/6000, SP, and

HACMP™ for AIX. Release Notes and readme files are also available.

You can install the AIX Information Center application from the AIX

Documentation CD. You can install and use it on a local system, or you can install it on a documentation server for intranet use.

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The IBM

^

hardware Information Center adds several new videos for customer-installable features and customer-replaceable parts.

For the latest AIX and pSeries (other than

Sserver

p5 hardware) information, refer to the AIX and pSeries Information Center at: http://publib.boulder.ibm.com/pseries/en_US/infocenter/base

For the latest IBM

^

p5 hardware information, see: http://publib.boulder.ibm.com/eserver/

1.6 LPAR Validation Tool

Another new functional role which has been incorporated into the Information

Center application is the ability to download new and useful tools. One example is the LPAR Validation Tool (LVT) on the InfoCenter Web site: http://www.ibm.com/servers/eserver/iseries/lpar/systemdesign.htm

The LVT assists you in the design of an LPAR system and provides an LPAR validation report that reflects your system requirements while not exceeding

LPAR recommendations.

Note: The LVT is not a marketing configurator, nor is it intended to replace

one.

Figure 1-3 on page 16 shows one way to locate the LVT from inside the

InfoCenter. You can find a detailed discussion about the LVT in 2.3, “Resource planning using LPAR Validation Tool” on page 42.

Chapter 1. Logical partitioning primer

15

Figure 1-3 InfoCenter - Planning for AIX logical partitions

1.7 Operating system support

With the introduction of the POWER5 processor and the POWER hypervisor, the ability of the supported operating systems to exploit the advancements in hardware and firmware is critical in leveraging all of the benefits of the

Sserver p5 and OpenPower server. This section describes what new and existing features are supported on each of the available operating systems.

AIX and Linux are supported operating systems that you can install on selected

Sserver

p5 models. A version of Linux is available for OpenPower systems.

These operating systems operate as independent logical servers. However, partitions share some system attributes, such as the system serial number, system model, and processor feature code. All other system attributes can vary among partitions.

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A mixed environment between AIX 5L Version 5.2 and Version 5.3 and Linux partitions on

Sserver

p5 servers is supported. Figure 1-4 shows a sample

configuration with mixed operating systems including different AIX versions. The first five partitions use dedicated processors. The AIX 5L Version 5.2 partition is not able to join the virtual I/O paths, but it provides all the known LPAR and

DLPAR features. It has to be configured with dedicated I/O adapters. The AIX 5L

Version 5.3 partitions using shared processors likewise can use dedicated storage and dedicated networking.

Figure 1-4 Mixed operating systems

Note: Partitions using virtualized shared resources cannot perform DLPAR

operations with partitions that are assigned dedicated hardware resources.

Note: The Linux and i5/OS™ partitions are able to participate in selected

virtual I/O operations on the

Sserver

p5 servers that are mixed operating environments.

Chapter 1. Logical partitioning primer

17

Table 1-4 illustrates the available operating system supported functions on

Sserver

p5 servers for partitions in a mixed operating system environment.

Table 1-4 Operating systems supported functions.

Function AIX 5.2 AIX 5.3 LInux SLES 9 Linux RHEL3 U3

Max 254 partitions

Micro-Partitioning

Capped and uncapped parititions

N

N

N

Y

Y

Y

Y

Y

Y

Y

Y

Y

Capacity on Demand

-processors

-memory

DLPAR

-processors

-memory

-I/O

POWER5 support

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Static

Y

N

Y

Static

Static

N

N

N

-base

-SMT

Virtual SCSI server

Virtual SCSI client

Virtual LAN

EEH Recovery

Large page support

Concurrent diagnostics

PCI Hot Plug

I/O drawer/tower concurrent add/remove

Memory resilience

Machine check handling

Y

Y

N

Y

Y

N

N

N

Y

N

N

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

N

Y

N

Y

Y

N

Y

Y

Y

N

Y

N

N

Y

N

N

Y

N

Y

Y

Y

N

Y

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1.7.1 AIX

To coincide with the POWER5 processor and new

Sserver

p5 product range,

IBM released the AIX 5L Version 5.3 operating system to leverage the new server’s 64-bit system and software architecture. This release supports new

IBM

^

p5 hardware systems, advanced POWER virtualization and symmetric multi-threaded POWER5 processors for improved system performance and utilization. AIX 5L Version 5.3 offers scalability for up to 64-way systems.

In addition to the introduction of the Advanced POWER Virtualization features,

AIX 5L Version 5.3 also includes new system management tools, security enhancements, support for NFS V4, POSIX Real-time, and the consolidation of both the online and CD-ROM based AIX documentation into the InfoCenter application.

Table 1-5 provides an overview of which advance POWER virtualization features

are available on both

Sserver

p5 supported AIX operating system platforms.

Table 1-5 AIX - supported features

Feature AIX 5L v5.2 ML4

POWER4 support Yes

POWER5 support

Dynamic LPAR -CPU

Dynamic LPAR - Memory

Dynamic LPAR -I/O

Yes

Yes

Yes

Yes

Micro-Partitioning technology

Virtual Ethernet

Virtual SCSI Client

>140 Partitions

No

No

No

No

Yes

Yes

Yes

Yes

AIX 5L v5.3

Yes

Yes

Yes

Yes

Yes

Note: Advanced POWER Virtualization is a separate additional feature that

you need to order with a

Sserver

p5 server.

Chapter 1. Logical partitioning primer

19

AIX 5L Version 5.2

In addition to all the enhancements and components provided in the former releases, AIX 5L Version 5.2 provides many enhancements. This section introduces briefly some of the enhancements that this book covers.

Note: AIX 5L Version 5.2 ML4 or later is required when using

Sserver

p5 servers.

Note: The 32-bit AIX kernel supports up to 96 GB of physical memory size

and 32-way processors, regardless of whether it is in a partition or it is running as a full system partition.

Fast reboot in a partitioned environment

Rebooting an operating system instance in a partition is much faster than a full system reboot of a comparable conventional

Sserver

p5 system because less hardware initialization is required.

Partition reboots are merely a re-establishment of the pSeries Open Firmware operating system boot loader environment and, by nature, are very quick. A Full

System Partition reboot repeats all the hardware initialization phases of the processors, caches, and memory. These phases are done by the service processor, and the I/O drawers and I/O adapters are done by the system firmware. When configuring all system resources in a single partition, hypervisor remains resident in memory. This configuration enables the extremely rapid re-establishment of the boot environment but requires the reservation of the first physical memory block by the hypervisor.

Dynamic logical partitioning

Starting with AIX 5L Version 5.2, AIX supports DLPAR, which allows you to add and remove resources dynamically without requiring a partition reboot. Both 32- and 64-bit kernels running in a partition support the DLPAR function. DLPAR provides the following features:

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Dynamic allocation and de-allocation of processors, memory, and PCI I/O adapters.

Capacity on Demand (CoD).

For a detailed explanation of DLPAR, see 5.1, “Dynamic logical partitioning overview” on page 140.

Although POWER5 processor based pSeries servers support AIX 5L Version

5.2, it is not possible to run an AIX 5L Version 5.2 partition with

Micro-Partitioning, Virtual SCSI, Virtual Ethernet, or SEAs.

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AIX 5L Version 5.3

This section introduces the AIX 5L Version 5.3 enhancements that this book discusses.

Micro-Partitioning

The system administrator defines the number of virtual processors that a partition can use as well as the actual physical processor capacity. The system administrator can define a partition with a processor capacity as small as 10 processor units. These 10 units represent 1/10 of a physical processor, and each processor can be shared by up to 10 shared processor partitions.

Shared processor partitions need dedicated memory. However, the partition I/O requirements can be supported through Virtual Ethernet and Virtual SCSI. Using all virtualization features, 254 shared processor partitions are supported.

Virtual Ethernet

The development of Virtual Ethernet enables inter-partition communications without the need of a dedicated physical network adapter. The system administrator can define in-memory point-to-point connections between partitions. These connections have the same characteristics as a high-bandwidth

Ethernet network and support multiple networking protocols, such as IPv4, IPv6, and ICMP.

Note: The maximum number of virtualized Ethernet adapters supported on a

Sserver

p5 AIX 5L Version 5.3 logical partition is 256.

Shared Ethernet Adapter

The Shared Ethernet Adapter (SEA) is a bridge from a physical Ethernet adapter to one or more Virtual Ethernet adapters. The adapter provides a secure route for partition network traffic to an external Ethernet network. With

Sserver

p5 servers, you must order this service with the Virtual I/O Server partition feature.

Virtual SCSI

The Virtual SCSI feature was developed to maximize the available hardware resources of the

Sserver

p5 servers. Because some

Sserver

p5 servers can support up to 254 partitions within the one server, the demand placed on the PCI slots and storage devices, either internal or attached, has increased significantly.

To meet these needs, the Virtual SCSI is designed to provide logical and physical volumes. From the Virtual I/O Server, these logical volumes appear to be SCSI disks on the client partition, giving the system administrator maximum flexibility in configuring partitions. At the time of the writing of this book, Virtual SCSI

Chapter 1. Logical partitioning primer

21

supports Fibre Channel, parallel SCSI, and SCSI RAID devices using SCSI protocol.

Virtual SCSI includes two additional services which also run on the Virtual I/O

Server: Reliable Command / Response Transport and Logical Remote DMA to service I/O requests for an I/O client. With these services, the I/O client uses the services of its own SCSI adapter.

Note: Because there are numerous limitations and considerations when

implementing the new features, these features are covered in more detail in

Chapter 4, “Virtualized resource management” on page 83.

1.7.2 Linux

With the release of the POWER5 processor based pSeries servers, the support for logical partitions running the Linux operating system has continued with the inclusion of the latest

Sserver

p5 and OpenPower server and virtualization features. Both the SUSE Linux Enterprise Server 9 (SLES9) and Red Hat

Enterprise Linux 3 (RHEL3) distributions have been designed to take advantage of the new POWER5 processor and virtualization features, such as

Micro-Partitioning, SMT, Virtual LAN, and Virtual SCSI client. The OpenPower product line supports only Linux as an operating system.

Support for various virtualization features is dependent on the Linux Distribution and Kernel version. At the time of the writing of this book, features such as

Micro-Partitioning, Simultaneous Multi-threading (available on SUSE Linux

Enterprise Server 9 only), Virtual Ethernet, and Virtual SCSI client are supported.

Also, some of the other

Sserver

p5 and OpenPower server features that are supported by SLES9 and RHEL3 are first failure data capture, double data rate

IBM Chipkill™ memory, error checking and correcting memory, Dynamic

Processor De-allocation, and hot-plug PCI slots, fans, and power.

For the latest updates to the SUSE or Red Hat Linux offering for POWER5 processor-based IBM

Sservers

, refer to: http://www.redhat.com/software http://www.suse.com

http://www.ibm.com/servers/eserver/linux/power/index.html

http://www.ibm.com/linux/whitepapers/

Note: One function not supported by Linux on

Sserver

p5 and OpenPower servers is Dynamic Memory allocation or de-allocation.

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Another key pSeries server component that continues to mature on the Linux operating systems is the increasing adoption of proven autonomic computing technologies from IBM.

A full list of reliability, availability, and scalability features that are supported by

SLES9 and RHEL3 is available at: http://www.ibm.com/servers/eserver/linux/power/whitepapers/linux_overview.pdf

Not all devices and features supported by the AIX operating system are supported in logical partitions that are running the Linux operating system. You can find information about external devices and features supported on

Sserver p5 server products at: http://www.ibm.com/servers/eserver/pseries/hardware/factsfeatures.html

http://www-1.ibm.com/servers/eserver/pseries/linux http://www.ibm.com/servers/eserver/pseries/linux/whitepapers/linux_pseries.html

Chapter 1. Logical partitioning primer

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