HP Instant Capacity (iCAP) Global Instant Capacity Resource Sharing, Example Core Rights Sharing

Global Instant Capacity Resource Sharing

Once a group is established, Instant Capacity resources (core, cell board, memory usage rights, and temporary capacity) can be shared among all the members of the group. Resource sharing can occur in several ways:

•During creation of the group, some members might have unused usage rights, so that by simply joining the group, additional usage rights are available for use by any member of the group.

•Even if there are no unused usage rights across the group, a member of the group can deactivate resources (cores, cells, or memory) to make additional usage rights available for activation by any other member in the group.

•Temporary capacity from all members of the group is available for use by any member of the group.

•Rights seizure allows the sharing of usage rights from failed partitions or failed servers.

Usage rights are shared by deactivating resources on one group member and then activating the resources on another member of the group. The system on which the resources are deactivated is lending usage rights to the activating (or borrowing) system. Activations and deactivations are performed on the individual member systems using the usual icapmodify commands (for cores) or parmodify commands (for cells) to effect this “loan” operation (also sometimes referred to as a transfer of usage rights).

Any temporary capacity available to individual members of the group is combined into a larger pool of temporary capacity that is available for consumption by any and all members of the group, as needed. Initiating usage of shared temporary capacity is the same as with individually purchased TiCAP: group members use the icapmodify -a-tcommand to activate shared temporary capacity. This differs from the sharing of usage rights in that temporary capacity is never a “loan” to be returned; it is always depleted through usage over time.

Example: Core Rights Sharing

In this scenario, core usage rights are not immediately available to any member of the group mygroup. Group member member1 has an immediate need for more processing power. However, group member member2 can loan a core usage right by deactivating one core.

First, member2, currently with 8 active cores, deactivates one core:

member2> icapmodify -d 1

7 cores are intended to be active and are currently active.

The core usage right from member2 is now available to any member of the group and can be used to activate an additional core on member1:

member1> icapmodify -a 1

8 cores are intended to be active and are currently active.

The output of the icapstatus command on loaning system member2 shows that the Number of Intended Active Cores and Number of active cores have decreased by 1, and the Number of inactive cores and Number of cores without usage rights have increased by 1. On borrowing system member1, the Number of Intended Active Cores and Number of active cores have increased by 1, and the Number of inactive cores and Number of cores without usage rights have decreased by 1.

The output of icapmanage -son the Group Manager system shows that the total number of cores without usage rights for the group has not changed.

Effect of Temporary Capacity

On systems where usage rights and temporary capacity are available, Instant Capacity uses usage rights before it uses temporary capacity. If temporary capacity is being used on at least one member system, a component on another member is deactivated, and a component on a third

112 Global Instant Capacity