Resizing partitions automatically with HP-UX Workload Manager

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WLM offers wlmpard for managing Instant Capacity or PPU resources. For more information on
this, see the wlmpard(1M) manpage. See also “Configuring automatic partition resizing” in this
paper.
With Instant Capacity v6 or earlier, do not include spaces in partition names. Also, if icod_stat
or icapstatus truncate the name of an nPartition, use parmodify to shorten the name so that it
is not truncated.
• Virtual machines—To run WLM on the Integrity VM Host, you must use a strictly host-based
configuration (designed exclusively for moving cores across HP-UX virtual partitions or nPartitions,
or for activating TiCAP cores or PPU cores). WLM will not run with FSS groups or pSets on Integrity
VM Hosts where guests are also running. In addition, ensure that the minimum number of cores
allocated to a WLM host is greater than or equal to the maximum number of virtual CPUs (vCPU
count) assigned to each VM guest. Otherwise, VM guests with a vCPU count greater or equal to
WLM’s minimum allocation could receive insufficient resources and eventually crash. For example,
if an Integrity VM host has 8 cores and three guests with 1, 2, and 4 virtual CPUs, respectively,
your WLM host should maintain an allocation of at least 4 cores at all times. You can achieve this
by using the WLM hmincpu keyword.
To run WLM within an Integrity VM (guest), you cannot use WLM integration with PPU and Instant
Capacity. As noted, WLM must continue allocating at least as many cores as the maximum number
of virtual CPUs in any VM guest on the system. In addition, you should specify a WLM interval
greater than 60 seconds. This helps ensure a fair allocation of CPU resources for FSS groups within
the Integrity VM guest.
• Global arbiter (wlmpard)—Do not adjust any WLM-managed partition while wlmpard is running.
This includes using vparmodify, icapmodify, or icod_modify to change the name,
configuration, or resources (CPU or memory) associated with the virtual partition or nPartition. This
also includes using parolrad to perform online cell (Cell OL*) operations on any cell in a WLM-
managed partition. To adjust a partition or cell, first shut down WLM (including wlmpard) on all
partitions that will be affected by the modification, then modify the partition. Restart WLM after
modifying the partition. (Changes to Instant Capacity affect the entire complex; changes to a virtual
partition affect the nPartition only, unless Instant Capacity is configured on the nPartition.) For
example, if WLM is managing two virtual partitions vParA and vParB, and you need to migrate
memory resources from vParA to vParB, you must shut down WLM in both virtual partitions. As
another example, to change the name of an nPartition, you must first shut down WLM in every
operating system instance across the entire complex, because the name change affects Instant
Capacity, and changes to Instant Capacity affect every nPartition across the complex.
HP recommends running the global arbiter (wlmpard) in secure mode. If you do not run it in secure
mode, a rogue user could manipulate the communications, resulting in one or more partitions being
granted an incorrect number of cores. To enable secure communications, set up security certificates
and distribute them to all systems or partitions being managed by the same WLM global arbiter.
For more information, see the HP-UX Workload Manager User’s Guide or the wlmcert(1M)
manpage. With secure communications enabled, wlmpard runs in secure mode by default when
you use the /sbin/init.d/wlm script to start WLM. (If you upgraded WLM, secure mode might not
be the default. Ensure that the WLMPARD_SECURE_ENABLE variable in /etc/rc.config.d/wlm is
enabled.) You can also activate global arbitration in secure mode by using the –s option with the
wlmpard command.
For information on using global arbitration with firewalls, see the wlmparconf(4) manpage.
• pSets—Simultaneous support of partitions and pSet-based workload groups requires the following:
– If Instant Capacity is available on the complex, it must be v7 or later.
– If HP-UX Virtual Partitions (vPars) is on the complex, it must be v4 (A.04.01) or later.