Dedicated processors

Dedicated processors are whole processors that are assigned to a single logical partition.

If you choose to assign dedicated processors to a logical partition, you must assign at least one processor to that logical partition. Likewise, if you choose to remove processor resources from a dedicated logical partition, you must remove at least one processor from the logical partition.

On systems that are managed by a Hardware Management Console (HMC), dedicated processors are assigned to logical partitions using partition profiles.

By default, a powered-off logical partition using dedicated processors has its processors available to uncapped logical partitions that use shared processors. If the uncapped logical partition needs additional processor resources, the uncapped logical partition can use the idle processors that belong to the powered-off dedicated logical partition, if the total number of processors used by the uncapped logical partition does not exceed the virtual processors assigned to the uncapped logical partition, and if the use of these idle processors does not cause the shared processor pool to exceed its maximum processing units. When you power on the dedicated logical partition while the uncapped logical partition is using the processors, the activated logical partition regains all of its processing resources. If you use the HMC, you can prevent dedicated processors from being used in the shared processor pool by disabling this function in the partition properties panels.

You can also set the properties of a logical partition using dedicated processors so that unused processing cycles on those dedicated processors can be made available to uncapped logical partitions while the dedicated processor logical partition is running. You can change the processor sharing mode of the dedicated processor logical partition at any time, without having to shut down and restart the logical partition.