Partitions can use one of two modes of processors on the iSeries™ server. The results of your capacity planning and system hardware configuration will help you make a decision about utilizing dedicated processors or the shared processor pool for each partition.
Depending on workload demands for each partition, one partition can use dedicated processors and another partition can use the shared processor pool.
Dedicated processors allows you to assign a whole processor to a partition. You can assign dedicated processors to a partition as long as processors are available or unassigned.
The shared processor pool allows you to assign partial processors to a partition. The processors are held in the shared processing pool and are shared among the logical partitions. A minimum of 0.10 processing units per virtual processor can be configured for any partition using shared processors. The primary partition may require more than 0.10 processing units when starting secondary partitions, otherwise timeout conditions may occur with resources communicating directly with the primary partition. Each system processing capacity and partition configuration needs to be evaluated to determine reasonable processor units for primary and secondary partitions.
To adjust to workload demands, you can move shared processing resources without needing to restart the partition. Use of the shared processor pool is preferred for small (less than one processor) partitions or where the use of a whole processor increments are too great for the partition.