HP vPars and Integrity Virtual Machines V6.1 Administrator Guide

operating system and its administrative functions. For more information about the memory
requirements of the VSP, see Section 3.1.3 (page 37).
Guest memory allocation can be viewed and allocated dynamically (that is, without stopping the
guest) by using dynamic memory parameters, as described in Section 11.9 (page 180).
7.1.8 Automatic cell balancing
When creating a guest, Integrity VM determines the best fitting locality domain for the new guest
when the VSP is predominantly Cell Local Memory(CLM). The hpvmstatus -C command provides
a list of guests with their memory type.
7.1.9 Reserved resources and resource over-commitment
HP-UX vPars and Integrity VM V6.1 allows the reservation of resources for virtual machines and
virtual partitions. Reservations imply that a resource will be available when it is needed, with the
intention of assuring that a virtual machine or virtual partition can boot at any time. The reserved
resources setting is managed for each individual virtual machine and virtual partition and is set
using the resources_reserved attribute (managed with the -x option of the hpvmcreate
and the hpvmmodify command). The default behavior of the vparcreate command is to set
resources_reserved to true when a virtual partition is created. However the hpvmcreate
command does not reserve resources by default when creating virtual machines or virtual partitions.
The resources_reserved attribute can be managed using the hpvmmodify command.
Resources that are reserved include memory, CPU and I/O devices. If a resource is assigned to a
virtual machine or virtual partition that has the resources_reserved=true, that same resource
cannot be assigned to a different virtual machine or virtual partition that also has
resources_reserved=true. It is also not possible to assign a resource to a virtual partition
or virtual machine that has resources_reserve=true, if that resource is not currently available.
For example if all the CPUs have been assigned to other reserving virtual machines or virtual
partitions, then it is not possible to assign CPUs to any additional reserving virtual machines or
virtual partitions. It is possible to assign resources to non-reserving virtual machines and virtual
partitions, however, it is not possible to boot them (because the resources assigned to that virtual
machine or virtual partition are reserved by other virtual machines or virtual partitions).
7.1.9.1 Resource over-commitment
In some circumstances, it is possible for resources to be over-committed, meaning that more resources
are assigned to reserving virtual machines and virtual partitions than are currently available. This
can occur if CPU, memory or other I/O devices are lost, such as removed during a VSP shutdown
or from a hardware failure. If all the resources of the VSP are assigned to virtual partitions or virtual
machines, and then later some of those resources are lost, the VSP will be in an over-committed
state. When this occurs, it is not possible to boot all of the reserving virtual machines or virtual
partitions. Virtual machines and virtual partitions with reserving resources will be allowed to boot
on a first-come first-served basis. And virtual machines and virtual partitions without resource
reservations will not be allowed to boot.
If CPU or memory resources are overcommitted, this state is logged in the /var/opt/hpvm/
common/command.log file. Additionally the overcommitted state is noted when displaying system
resources using the hpvmstatus -s command. For example:
# hpvmstatus -s
[HPVM Server System Resources]
*** VSP resources are over-committed ***
vPar/VM types supported by this VSP = Shared
Processor speed = 1596 Mhz
Total physical memory = 16278 Mbytes
Total number of operable system cores = 8
CPU cores allocated for VSP = 1
CPU cores allocated for vPars and VMs = 7
7.1 Specifying virtual machine characteristics 79