HP Instant Capacity Version 10.x User Guide (5900-2170, January 2012)

date for a rights seizure operation effectively terminates the period during which the core usage
rights are available to other group members for purposes of disaster recovery. If none of the member
partitions are reachable by the expiration date for a particular member, the usage rights are
automatically restored (reassigned) to the member partition (or complex, in the case of unassigned
seized rights) from which they were seized. However, note that if the seized usage rights have
been redeployed to other members and are not released at the expiration time, the group may go
out of compliance or temporary capacity may be used to maintain compliance.
If any partition of the inaccessible member from which rights seizures were deferred reconnects to
the group before the expiration date, the seized core usage rights (for all partitions) are finalized
as a loan from the member to the group, the expiration date is no longer relevant, and the usage
rights can thereafter be manipulated with normal icapmodify operations.
The icapmanage -x operation can be performed after for each hard partition on the member.
Down partitions with powered-on cells
Partitions that are not running an iCAP daemon are assumed to be running another OS and using
all cores on cells configured in the partition. The iCAP software can avoid this assumption when
all cells configured in the partition are powered down. 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 seized 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 iCAP contract. Cells can be made inactive by
removing them from the partition, shutting down the partition from within the OS by using
shutdown -R -H, or with the MP RR command.
TiCAP and rights seizure
iCAP is designed to stop using temporary capacity and instead take advantage of usage rights if
any become available. If temporary capacity is in use during a failover sequence, the activation
on the failover node might need to specify the use of temporary capacity. After the rights have
been seized and before the activation on the failover node, there is a window of time when the
iCAP daemons (on other partitions in the group) can wake up and start using the seized usage
rights to stop using temporary capacity. If this happens, the seized usage rights are no longer
available for the failover activation.
By specifying the use of temporary capacity on failover activation, you guarantee that the core
activations needed for failover will occur. The total temporary capacity consumption across the
group remains the same, even though the temporary capacity might be consumed on the failover
server instead of on the original server.
If, for some reason, it is important to keep the temporary capacity usage to a particular server,
you can manually deactivate the temporary capacity-consuming cores before doing the failover
activations, and then reactivate the temporary capacity usage after the failover activations. For
similar reasons, it might also be important to make sure other activations are not occurring
simultaneously during a failover sequence.
Other considerations
Rights seizure can be used as part of an automatic failover system, but be sure that resources are
seized appropriately and in a manner that does not cause problems when the problem is corrected.
The iCAP software determines that the partition is down based on whether the ping command is
unsuccessful for the partition. In some circumstances, ping might be unsuccessful but the system
remains functional (for example, if a network connection is interrupted). In this case, rights seizure
may be inappropriate and leave workloads without the necessary resources.
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