PR/SM shared partitions

PR/SM configurations supporting multiple partitions, all sharing CPs, support concurrent CP upgrades. PR/SM code, once signaled that one or more central processors have been made available to the configuration, will vary them online automatically into the shared pool of physical cores and begin full utilization of the added capacity. In the following example, three partitions sharing eight physical cores are able to share the increased capacity resulting from a nondisruptive upgrade to a 9- way server without any other configuration changes. In the second upgrade scenario, Partition 1 is additionally changed from a 4-way to a 5-way partition nondisruptively. The preparation for this is straightforward and easy. Simply define and activate logical Partition 1 with four initial and one reserved logical cores (see Figure 1 for a similar example). At the time of the concurrent CP upgrade, the 21CS VSEn command or the z/OS CONFIG CPU command can be used in Partition 1 to configure a fifth CP online to the shared partition without interruption to any logical partition.