HP OpenVMS Alpha Partitioning and Galaxy Guide

Managing Workloads With Partitions

Using Hard and Soft Partitions on OpenVMS Systems

Partitioning for the AlphaServ

OpenVMS PartitioningGuidelines  

When deciding whether to use hard or soft partitions on AlphaServerES or GS series systems, note the following:

• For the AlphaServer GS80/160/320,each partition (hard or soft) must have its own console line; for AlphaServerES47/ES80 and GS1280 systems, a network connection to the consoleor direct console access is needed. For the AlphaServer GS80/160/320,each QBB in the system can have one console line.



• You can have multiple softpartitions within a hard partition.



• As an example of the licensing policy, you onlyneed one cluster license for the entire AlphaServer ES or GS seriessystem. It does not matter how many instances exist or how theyare clustered, internally or externally. For additional informationon licensing, see Installing Licenses ofthis manual and the licensing policy itself.

In an OpenVMS Galaxy computing environment, MOP(Maintenance Operations Protocol) Booting is only supported on Instance0.

• Hard partitionsshould be on building block boundaries either on quad (QBB) or system(SBB) building blocks. GS80/160/320 systems use QBBs, and ES47/ES80/GS1280systems use SBBs. A hard partition can contain more than one SBBor QBB. For high availability, HP recommends that hard partitionsbe created on system building block boundaries. No partition canhave more than 32 processors.
  
  Only the GS1280can use subsystem building blocks (SSBBs). A subsystem buildingblock in a GS1280 is a 2P building block within an 8P building block.
  
  TheAlphaServer ES47/ES80 system uses two-processor (2P) system buildingblocks, and the GS1280 uses eight-processor (8P) SBBs. A 2P SBBincludes some I/O, but with an 8P SBB, the user must supply externalI/O connections. Both subsystem and system building blocks can beused for hard partitions to provide fault isolation. See System Building Blocks for the two types of SBBs with theirvariants.



• Soft partitions do not have to be on building blockboundaries.
  
  

  Table 1    System Building Blocks

  System	SBB Type	Model	Maximum Number of Hard Partitions
  ES47/ES80	2P (2x1)	2	1
  	2P (2x2)	4	2
  ES80	2P (2x3)	6	3
  	2P (2x4)	8	4
  GS1280	8P (8x1)	8	4 - using 2P SSBBs
  	8P (8x2)	16	8 - using 2P SSBBs
  	8P (8x1)	8	1 - using 8P SBBs
  	8P (8x2)	16	2 - using 8P SBBs
  	8P (8x4)	32	4 - using 8P SBBs

  
  

Setup for partitions must follow setup rules.

For QBB-based systems, each partition (hard or soft) musthave its own console line. Note that each QBB in the system canhave one console line in it. Therefore, the maximum number of partitions(hard or soft) in the system equals the number of QBBs in the system.

Hard Partition Rules:

Each hard partition must have:

• Console accesswith the Management Backplane Module (MBM) or telnet



• An I/O drawer per partition(an internal drawer on the ES47/ES80 is sufficient).



• To avoid single points offailure, you must set up on building block boundaries.

For maximum fault isolation and availability, ES47/ES80/GS1280systems should be hard partitioned on system building block boundaries.For the ES47/ES80, this means on the 2P SBB boundary. For the GS1280, itis the 8P SBB boundary. When configured on system building blockboundaries, hard partitions will have no single points of failurefor the entire system. Power and cooling are self-contained withinthe hard partition. The interprocessor links will be turned off.This is the most robust form of partitioning. Note that a robusthard partition may contain multiple system building blocks.

For the GS1280 system, it is possible to hard partition thesystem building blocks into subsystem building blocks (SSBBs). An8P SBB may be partitioned down to the 2P level. These hard partitionsare separately powered and offer the ability to power off a dual-CPUmodule if needed for repair. This level of partitioning does notoffer the fault isolation and robustness of a system that is partitionedon 8P SBB boundaries.

For hard partitions at the 8P or 2P SBB level, an individualserial console line per hard partition is supported. When an 8PSBB is subpartitioned into multiple hard partitions, the serialconsole can only connect to one subpartition at a time. If simultaneousaccess to all subpartition consoles is needed, then telnet sessionsacross the management LAN must be used. The section Process for Partition Setup describes the partition setupprocess, and the section Hard Partition Configuration Example illustrates configuration setup with two examples.

Console accesswith the MBM or telnet. An I/O drawer per partition(an internal drawer on the ES47/ES80 is sufficient). A primary CPU. Private and shared memoryfor the operating system and applications. Shared memory is notnecessary for independent instances but is required for shared memoryapplications. Process for PartitionSetup   The basic process for setting up hard and soft partitionsat the Management Backplane Module (MBM or SCM) is the following: Create hard and soft partitions. Assign CPU, IO, and memoryresources to the partitions. Power on CPUs and connectto consoles. Check and reset console environmentvariables if necessary. This process is illustrated in Partitioning Sequence.   Figure 1  Partitioning Sequence   Physical hardware and ownership relationships are representedas branches of a single configuration tree in each system. Partitions,both hard and soft, can be thought of as ownership containers representingthe accessibility and visibility of all resources in the configuration.Thetop level configuration branch shown in System Configuration Tree includes both the hardware and software configurationtrees.   Figure 2  System Configuration Tree   In the hardware configuration tree shown in Hardware Configuration Tree, the physical nature of the box isdelimited. Each bullet or filled circle represents a node in thetree (where node is not an individual computer but a point of connectionin the tree). From the hardware root the tree divides to the buildingblocks, and within each building block to the major system categoriessuch as memory, input/output, and CPU. At a lower level in the configurationtree, within I/O, for example, the tree branches to individual deviceson the system, and so on. Each node in the tree has a definitionthat includes its parent, its siblings, its children, and its ownership.Figure 3  Hardware Configuration Tree

The scope of a partition is always on a branch, up or down,but never across branches.A soft partition, as shown in Software Configuration Tree, always looks up its tree for potentially available resources.The hard partition owns assigned resources that are available toall nodes below it.

In general, resources that are in use by a specific instanceof an operating system are owned by the soft partition that representsthat partition in the configuration tree. The cooperative push model ineffect with multiple instances in a hard partition dictates thatresources owned by a given instance can only be given away, nottaken. A resource owned by nodes further up the tree may be usedcooperatively (for example, shared memory at the community level),assigned down the tree to a specific soft partition, or up the tree whereit becomes available to potentially multiple soft partitions.

Direct assignment of resources between soft partitions iscalled migration; only CPUs can move between soft partitions. Themigration partitioning feature is not specific to Galaxy: CPUs canbe migrated from any soft partition to another in the same hardpartition without direct communication between them. All managementof CPU resources is initiated with OpenVMS DCL SET/STOP CPU commands.

Migration ResES47/ES80/GS1280 Systems: You cannot migrate a CPU thathas attached IO. To check if there is attached IO, either check thephysical configuration for a hose attached to a CPU, or use theMBM show partition output: in the IOPs section, a CPU with attachedIO has a dashed line; the CPU ID is the corresponding PID in theCPUs section of the show partition output. (Hard Partition Configuration Example for an example.)

Figure 4  Software Configuration Tree

Using Hard and Soft Partitions on OpenVMS Systems

Partitioning for the AlphaServ