HP Instant Capacity Version 10.x User Guide (5900-1581, March 2011)

core usage right per active cell. Any core usage rights in excess of this are made available for use
elsewhere in the GiCAP group.
The seizure of core usage rights from a fully unavailable member is temporary. After 10 days, the
usage rights are automatically restored to the member from which they were seized. Seizure of
core usage rights from a member with at least one accessible partition (at the time of rights seizure)
do not expire. The icapmanage -z command allows you to restore previously seized core usage
rights to a specified host.
The following command seizes core usage rights from a partition that is unavailable, so that the
rights are available for other group member activations:
icapmanage -x mypar1.node.corp.com
When to Migrate Usage Rights and When to Seize Usage Rights
Here are some basic guidelines for determining when to seize usage rights or when to simply
migrate those rights:
• Planned downtime and load balancing
Whenever possible, migrate usage rights by deactivating cores in one partition and then
activating cores in another partition. The involved partitions do not need to be part of the
same member server. For example, if maintenance is planned such that a partition is
unavailable for a period of time, deactivate cores in that partition before it becomes
unavailable. The usage rights from this partition are available to the entire GiCAP group
during this maintenance period.
• Unplanned downtime
When an nPartition or server goes down unexpectedly, seize the usage rights from that
nPartition to make them available to the remaining GiCAP group members.
Effects of Rights Seizure
Rights seizure takes almost all the available usage rights from the hard partition containing the
specified host, leaving only enough usage rights to be able to boot (one core usage right for each
cell configured for use-on-next-boot (UONB)). The partition has the value intended active set
to the required minimum (one core per configured cell) and the value actual active set to
zero. The number of core usage rights seized is equal to the difference between the new value for
intended active and the greater of the old values for intended active and actual
active. These seized core usage rights are available for use elsewhere in the GiCAP group.
Although rights can be seized from any hard partition that is unavailable, the Instant Capacity
software makes some additional restrictions when all partitions of a complex are unavailable. As
a result, there are different behaviors and constraints depending on whether any partitions can be
contacted on the specified member complex.
If, at the time of rights seizure, at least one member partition can be contacted, then the software
is able to make an immediate adjustment to the available core usage rights, just as if a normal
migration operation using icapmodify -d had been performed before the specified hard partition
stopped running. This makes core usage rights available for potential loans to other member
systems. In this situation, the seized core usage rights do not have an expiration date. However,
because other member partitions are running Instant Capacity software, you can assume that the
unreachable partition is using all cores on cells configured for that partition. Unless an explicit
restore operation is performed, when the failed partition is rebooted it will have only the minimum
number of core usage rights left after the rights seizure. Because of this, cells in partitions from
which usage rights have been acquired should be rebooted or made inactive within 12 hours. If
this is not done, the partition may begin to consume temporary capacity. If temporary capacity is
not available, the complex may no longer be in compliance with the Instant Capacity contract.
84 Global Instant Capacity