HP Instant Capacity User's Guide for Version 9.x

4.4 Activating Cores
The icapmodify command provides the ability to increase processing capacity instantly by
activating cores with available usage rights in Instant Capacity systems. At any time, any number
of inactive cores with usage rights can be activated, as long as sufficient usage rights are available.
Whether you are activating or deactivating cores, the icapmodify command adjusts only the
number of dynamic cores, and it does not explicitly identify specific cores.
Activating Cores in nPartitions
The Instant Capacity software provides two types of activation:
• Instant (icapmodify command’s default behavior) — activation occurs immediately.
• Deferred (icapmodify -D) — activation occurs after the next reboot of the partition.
Instant activation of cores occurs when the icapmodify command is used with either the -a
or -s option, and the -D option is not specified. If the -s option is used, the number of cores
specified must be greater than the number of currently active cores.
Deferred activation of cores occurs when the icapmodify command is used with both the -D
option and either the -a or -s option. With the deferred option (-D), core activation occurs after
a reboot of the partition. The reboot (and the core activation) can take place at a planned time.
For example, if you activate cores in deferred activation mode and schedule a partition reboot
to occur on the first day of the next month, the cores are activated at that time.
IMPORTANT: If you shut down a partition for 12 hours or more, it should be powered off or
deactivated to avoid additional charges. To power off the partition, execute the PE command
from the system MP.
On HP-UX systems, always use the shutdown -R -H command when shutting down or
rebooting an Instant Capacity partition. If the partition is already shut down, use the rr command
from the system MP to reset cells for reconfiguring. For information about the shutdown
command, see shutdown(1M).
On OpenVMS systems, always use the sys$system:shutdown.com command procedure
when shutting down or rebooting an Instant Capacity partition.
Although a deferred activation does not immediately change the number of active cores, the
intended active value is changed. This change does affect compliance checking, even before the
partition reboot occurs. In particular, compliance checking is calculated as if the activation had
not been deferred.
IMPORTANT: On OpenVMS Instant Capacity systems, HP strongly recommends that you
activate cores using the icapmodify or the ICAP SET command. The use of the START CPU
command on an Instant Capacity system can result in unintended consequences, such as a
reduction of available temporary capacity. Another unintended side effect might be the adjustment
in core usage across the complex, depending on the intended core settings on the partition where
the START CPU command was issued.
To activate one or more inactive cores, use the icapmodify command as root. For more
information about this command, see icapmodify((1M)).
Constraints
The Instant Capacity software does not activate cores that are marked for deconfiguration. Also,
you cannot use Instant Capacity to activate more cores than are configured in the current
nPartition. If you want more cores, you must modify the nPartition with the parmodify
command. You can use Instant Capacity to activate more cores than are configured into the
current virtual partition, but only if the associated nPartition contains enough unassigned cores
4.4 Activating Cores 55