Deactivating Processors

Deactivating Processors in nPartitions

You have the ability to decrease processor capacity instantly on HP enterprise servers with the Instant Capacity software. Any number of active processors can be deactivated at any time, within the partition constraints listed below. Processor deactivation can be useful for load balancing processors in nPartitions (hard partitions) of Instant Capacity systems. See “Instant Capacity Integration with Virtual Partitions” for details about deactivating processors in virtual partitions.

The software provides two types of processor deactivation:

Instant deactivation of processors occurs when the icod_modify command is used with the -d option, and the -D option is not specified.

Deferred deactivation of processors occurs when the icod_modify command is used with both the -D and -d options specified. With the deferred option (-D), processor deactivation occurs after a reboot of the partition. The scheduled timing of the reboot (and the processor deactivation) can take place at a planned time. For example, if you deactivate processors in deferred activation mode and schedule a partition reboot to occur on the first day of the next month, the processors are deactivated at that time.

To deactivate one or more active processors, use the icod_modify command as root. See the manpage icod_modify(1M) for details.

Partition Constraints

An nPartition must have a minimum of one active processor for each active cell. Deactivation of processors is limited by this rule. If the deactivation applies to a virtual partition, additional constraints may apply, such as the minimum number of processors specified for the virtual partition.

Deactivation Example Session for Hardware-partitionable Systems

The following example shows you how to deactivate an active processor. At the beginning of this deactivation session, there are a total of 4 processors in the partition; 3 processors are active and 1 is inactive. In this example, 1 active processor is deactivated, leaving the partition with 2 active processors and 2 inactive processors. As with activation, you do not specify a particular processor to be deactivated. You specify only a number of processors to be deactivated.

Example 4-4 Deactivating an Active Processor

/usr/sbin/icod_modify -d 1

2 processors are now active, and 2 processors are specified to be active after the next reboot.

	NOTE: In the above deactivation example, the processor deactivation is instant (that is, does not require a reboot). To defer the deactivation (until the next reboot) add the -D option to the command. See the manpage icod_modify(1M) for details.

The icod_modify command allows you to deactivate processors with the -d option, or set the total number of active processors with the -s option. For example, the icod_modify -d 1 command/option deactivates 1 additional processor in a partition. The icod_modify -s 2 command/option sets the total number of active processors in a partition to 2.