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

Whenever an Instant Capacity component without usage rights is purchased, an amount of Instant
Access Capacity (IAC) might also be included. Instant Access Capacity is exactly the same as
temporary capacity, except it is automatically provided with an Instant Capacity component and
is not separately purchased. It provides an immediate buffer of temporary capacity in case extra
capacity is needed before there is time to purchase either an RTU codeword, a temporary capacity
codeword, or to setup a Global Instant Capacity (GiCAP) group.
Temporary capacity can be added to the complex by applying a temporary capacity codeword
(available from the HP Utility Pricing Solutions portal) using the icapmodify command. Information
about the amount of temporary capacity time remaining on a complex can be obtained by executing
the icapstatus command. A warning is also sent via email when the temporary capacity balance
is expected to be depleted within a certain period of time.
The icapmodify command allows activating a core using temporary capacity only if at least 30
minutes of temporary capacity is available for each core being activated.
Whenever temporary capacity has been applied to a system (or if the complex is part of a GiCAP
group), extra care must be taken to avoid situations that cause the Instant Capacity software on
one nPartition of a group member to make assumptions that all cores might be active on another
nPartition of the member, for example, when the nPartition is making boot-related configuration
changes (at EFI or BCH). If left in this state for more than 12 hours, unexpected temporary capacity
may be consumed on the complex.
Instant Capacity Cell Board
Instant Capacity Cell Board offers a way to have additional (inactive) cell board capacity for your
system. These Instant Capacity cell boards, which contain memory and cores, can be activated
after a cell RTU codeword is obtained from the HP Utility Pricing Solutions portal and is applied
to the complex using the icapmodify command. To activate a cell, you must have usage rights
for all memory attached to the cell and at least one core.
Global Instant Capacity
Global Instant Capacity (GiCAP) provides HP customers with the flexibility to move usage rights
for Instant Capacity components within a group of servers. It also provides “pooled” temporary
capacity across the group. This has several potential benefits: cost-effective high availability, more
adaptable load balancing, and more efficient and easier use of temporary capacity.
For example, in case of planned or unplanned down time, a customer can transfer usage rights
from a failed partition on one server to one or more other servers in the group that are providing
backup availability, thus allowing additional activations of iCAP components on the backup servers.
Without GiCAP, the only way to provide this failover scenario is to provision each server with an
adequate amount of temporary capacity.
A similar scenario exists for load balancing. Rather than using temporary capacity whenever a
server is overloaded (peak profiles for all workloads on a server), usage rights can be transferred
from other servers in the GiCAP group that have extra capacity. These borrowed usage rights
enable new component activations on the overloaded system.
Pooled temporary capacity for a group of servers is more efficient because all temporary capacity
is available to all servers in the GiCAP group. It is also easier to manage if temporary capacity
needs to be applied to only one member of the group and monitored across the group instead of
monitoring TiCAP for each member complex.
GiCAP Groups
Global Instant Capacity is built on the concept of a server group, or GiCAP group. The group
consists of a list of server complexes that are allowed to share Instant Capacity usage rights (for
cores, cell boards, and memory) and temporary capacity. There are no constraints on the number
of servers allowed in a group, but grouping rules defined by HP specify the types of servers allowed
to group together.
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