HP Instant Capacity User's Guide for Versions 8.x

Global Instant Capacity Resource Sharing
Once a group has been established, Instant Capacity resources (core, cell board, memory usage
rights, and temporary capacity) may be shared among all the members of the group. The sharing
can occur in several ways:
• During creation of the group, some members may 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 may
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
resources on another member of the group. The system on which the resources were deactivated
is loaning 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 -t command to activate shared
temporary capacity. Note that this differs from the sharing of usage rights in that temporary
capacity is never a “loan” to be returned; it is always depleted through its usage over time.
Example 7-6 Core Rights Sharing
In the following scenario, no member of the group mygroup has core usage rights immediately
available. 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, will deactivate 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 for 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 the loaning system member2 will show that the
Number of Intended Active Cores and Number of active cores have decreased by
one, and the Number of inactive cores and Number of cores without usage
rights have increased by one. On the borrowing system member1, the Number of Intended
Active Cores and Number of active cores have increased by one, and the Number of
inactive cores and Number of cores without usage rights have decreased by one.
The output of icapmanage -s on the Group Manager system will show that the total number
of cores without usage rights for the group has not changed.
Effect of Temporary Capacity
In systems where usage rights and temporary capacity are available, Instant Capacity tends to
use usage rights before temporary capacity. In a situation where temporary capacity is being
used on at least one member system, a component on another member is deactivated, and a
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