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

Cells may 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.
If, at the time of rights seizure, all member partitions are unreachable, the rights seizure is deferred
and must be viewed as a limited and immediate loan of usage rights from the specified partition
to the group. This loan of seized usage rights expires in 10 days. Upon expiration, usage rights
are automatically restored to the member partitions from which they were seized. The expiration
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 once for each hard partition on the member.
Down Partitions with Powered-On Cells
Partitions that are not running an Instant Capacity daemon are assumed to be running another OS
and using all cores on cells configured in the partition. The Instant Capacity 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 Instant Capacity 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.
Temporary Capacity and Rights Seizure
Instant Capacity 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 in order 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.
Rights Seizure 85