Source and destination servers in a partition mobility environment

Two servers are involved in partition mobility that is managed by a Hardware Management Console (HMC). The source server is the server from which you want to migrate the logical partition, and the destination server is the server to which you want to migrate the logical partition.

The source and destination servers must be POWER8 processor-based servers, or later, to participate in partition mobility. The destination server must have enough available processor and memory resources to allow the mobile partition to run on its server.

DPO is a hypervisor function initiated by the HMC. DPO rearranges the logical partition processors and memory on the system, to improve the affinity between processors and memory of the logical partition. When DPO is running, mobility operations targeting the system being optimized will be blocked. To continue with the migration, you must either wait for the DPO operation to complete, or manually stop the DPO operation.

Huge pages

Huge pages can improve performance in specific environments what require a high degree of parallelism, such as in DB2® partitioned database environments. You can specify the minimum, desired, and maximum number of huge pages to assign to a logical partition when you create the logical partition or partition profile.

A logical partition cannot participate in active partition mobility if huge pages are used. However, an inactive partition migration can be performed if the mobile partition uses huge pages. The partition profile will maintain the huge page resources, but the specified number of huge page resources may not be available on the destination server, in which case the logical partition will boot without some or all these huge pages after the inactive migration.

Inactive partition mobility policy

For inactive partition mobility, you can select one of the following configurations in the HMC for memory and processor-related settings of the mobile partition. If you are able to start the partition, and you select the current configuration as the mobility policy, then memory and processor-related settings are obtained from the partition state that is defined in the hypervisor. However, if you are unable to start the partition, or you select the last activated profile on the source server as the mobility policy, then memory and processor-related settings are obtained from the last activated profile on the source server. The mobility policy that you select applies to all inactive migrations, where the source server is the server on which you have set the policy.

For inactive partition mobility validation, the HMC either uses the hypervisor data or the last activated profile data to verify that the partition can be migrated to the destination server.