Changing the paging VIOS partitions assigned to the shared memory pool
You can use the Hardware Management Console (HMC) to change the Virtual I/O Server (VIOS) logical partitions (hereafter referred to as paging VIOS partitions) that are assigned to the shared memory pool.
Before you begin
- Shut down all of the shared memory partitions that use the paging VIOS partition that you plan to change. You must shut down all of the shared memory partitions that use the paging VIOS partition (that you plan to change) as the primary paging VIOS partition, and you must shut down all of the shared memory partitions that use the paging VIOS partition (that you plan to change) as the secondary paging VIOS partition. For instructions, see Shutting down and restarting logical partitions.
- Verify that the VIOS logical partition that you plan to assign to the shared memory pool as a paging VIOS partition is running. (This is the VIOS logical partition to which you plan to change the VIOS assignment of a paging VIOS partition.)
- Verify that you are a super administrator or an operator of the HMC.
About this task
The following table describes the situations in which you can change a paging VIOS partition.
| State of one paging VIOS partition | State of the other paging VIOS partition | Change options |
|---|---|---|
| Running or shut down | None. Only one paging VIOS partition is assigned to the shared memory pool. | You can change the VIOS assignment of the paging VIOS partition. In this situation, you also need to add the paging space devices to which the changed paging VIOS partition has access. |
| Running | Running | You can change the VIOS assignment of one of the paging VIOS partitions. You cannot change the VIOS assignment of both paging VIOS partitions at the same time. |
| Running | Shut down | You can change the VIOS assignment of only the paging VIOS partition that is shut down. |
| Shut down | Running | You can change the VIOS assignment of only the paging VIOS partition that is shut down. |
| Shut down | Shut down | You cannot change the VIOS assignment of either paging VIOS partition. Instead, you can remove the paging VIOS partition that you do not want to change and then change the VIOS assignment of the remaining paging VIOS partition. In this situation, you also need to add the paging space devices to which the changed paging VIOS partition has access. |
When you change the VIOS assignment of a paging VIOS partition, the following configuration changes occur to the paging space devices:
- Paging space devices that were common become independent if only one paging VIOS partition can access them.
- Paging space devices that were common remain common if both paging VIOS partitions can access them. (These are paging space devices to which all three VIOS logical partitions have access. The three VIOS logical partitions are the two VIOS logical partitions that were originally assigned to the shared memory pool as paging VIOS partitions plus the VIOS logical partition that you assigned as a paging VIOS partition when you changed the VIOS assignment of a paging VIOS partition.)
- Paging space devices that were independent become common if both paging VIOS partitions can access them.
When you change the VIOS assignment of a paging VIOS partition, the HMC changes the configuration of the shared memory partitions to use the VIOS logical partition that you assigned as the paging VIOS partition. When you activate the shared memory partition, the HMC automatically reflects the name of the VIOS logical partition that you assigned as the paging VIOS partition in the partition profile. The following examples explain this automatic change in more detail:
- A shared memory partition uses only one paging VIOS partition and you change the VIOS assignment of that paging VIOS partition from VIOS_A to VIOS_B. When you activate the shared memory partition, the HMC automatically shows VIOS_B as the paging VIOS partition in the partition profile.
- Two paging VIOS partitions are assigned to the shared memory pool. VIOS_A is assigned to the shared memory pool as PVP1 and VIOS_B is assigned to the shared memory pool as PVP2. A shared memory partition uses PVP1 as the primary paging VIOS partition and PVP2 as the secondary paging VIOS partition. You change the VIOS assignment of PVP1 from VIOS_A to VIOS_C. When you activate the shared memory partition, the HMC automatically shows VIOS_C as the primary paging VIOS partition and VIOS_B as the secondary paging VIOS partition.
For more information about managing shared memory pools, see Managing shared memory pools.
What to do next
- If necessary, assign paging space devices to the shared memory
pool. For instructions, see Adding and removing paging space devices to and from the shared memory pool.
You might need to add paging space devices in the following situations:
- You changed the VIOS assignment of the only paging VIOS partition that is assigned to the shared memory pool. The VIOS logical partition that you assigned as the paging VIOS partition has access to different paging space devices than the VIOS logical partition that was previously assigned as the paging VIOS partition. The paging space devices to which the current paging VIOS partition has access must be assigned to the shared memory pool for the shared memory partitions to use them.
- You removed a paging VIOS partition that was shut down and then changed the VIOS assignment of the other paging VIOS partition that was also shut down. Because you removed a paging VIOS partition from the shared memory pool, you changed the VIOS assignment of the only paging VIOS partition that is assigned to the shared memory pool. The VIOS logical partition that you assigned as the paging VIOS partition has access to different paging space devices than the VIOS logical partition that was previously assigned as the paging VIOS partition. The paging space devices to which the current paging VIOS partition has access must be assigned to the shared memory pool for the shared memory partitions to use them.
- You changed the VIOS assignment of a paging VIOS partition that provided independent paging space devices to shared memory partitions. The VIOS logical partition that you assigned as the paging VIOS partition has access to different paging space devices than the VIOS logical partition that was previously assigned as the paging VIOS partition. The independent paging space devices to which the current paging VIOS partition has access must be assigned to the shared memory pool for the shared memory partitions to continue to use independent paging space devices.
- Activate all of the shared memory partitions that you previously shut down so that your changes can take effect. For instructions, see Activating a logical partition.