HP Instant Capacity (iCAP) manual Effects of Rights Seizure

Rights Seizure

GiCAP disaster recovery was introduced in Instant Capacity version 8.02.01 and provides the ability to “seize” core usage rights from a GiCAP member that is off line because of some disaster, and transfer them to the Group Manager. Then, using normal activation commands, these usage rights can be used to activate additional processor cores on other group members to increase capacity. Rights seizure can be used to provide disaster recovery when all partitions of a GiCAP member fail. It also enables the restoration of usage rights to the member once contact has been restored.

When a failure occurs on a partition in an active group member, use the icapmanage -xcommand to acquire core usage rights from the specified host to make them available to other group members. This is known as rights seizure. The specified host must be known to the GiCAP Group Manager (it appears in the output of the icapmanage -scommand) and not currently running. That and any other (vPar) hosts associated with the same hard partition are verified to be unreachable by the GiCAP Group Manager. The icapmanage -xcommand verifies with each known host on the hard partition. The hard partition containing the specified host is left with one 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 -zcommand 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.

122 Global Instant Capacity