Subscribe to this informationAdding and removing I/O entitled memory dynamically to and from a shared memory partition
You can dynamically add and remove I/O entitled memory to and from a running logical partition that uses shared memory (hereafter referred to as a shared memory partition) using the Hardware Management Console (HMC). This allows you to increase and decrease the maximum amount of physical memory that is assigned to the shared memory partition for its I/O devices without having to shut down the shared memory partition.
A Linux shared memory partition supports the dynamic addition and removal of I/O entitled memory resources only if the DynamicRM tool package is installed on the Linux shared memory partition. To download the DynamicRM tool package, see the Service and productivity tools for Linux on POWER® systems Web site.
You can increase the amount of I/O entitled memory that is assigned to a shared memory partition when the sum of I/O entitled memory that is assigned to all shared memory partitions in the shared memory pool is less than the size of the shared memory pool minus the required amount of reserved firmware memory. If there is not enough physical memory in the shared memory pool by which to increase the I/O entitled memory to the amount specified, you can release to the hypervisor the physical memory that is currently assigned to other shared memory partitions that are shut down. The hypervisor can then assign the released physical memory to the shared memory partition that needs more I/O entitled memory.
You can decrease the amount of I/O entitled memory that is assigned to a shared memory partition only when the shared memory partition requires less physical memory for its I/O devices than the amount of I/O entitled memory that is assigned to the shared memory partition. For example, you assign 128 MB of I/O entitled memory to a shared memory partition. The shared memory partition requires a minimum of 64 MB for its I/O devices. Thus, you can decrease the I/O entitled memory that is assigned to the shared memory partition by up to 64 MB. For instructions about how to view the assigned, minimum, optimal, and maximum I/O entitled memory used by a shared memory partition, see Determining the I/O entitled memory for a shared memory partition.
To dynamically add and remove I/O entitled memory to and from a running shared memory partition using the HMC, you must be a super administrator, service representative, product engineer, or operator of the HMC.
- In the navigation pane, expand .
- Click the server on which the shared memory partition runs.
- In the work pane, select the shared memory partition to which you want to add or remove logical memory.
- From the Tasks menu, click . The Add/Remove Memory Resources window is displayed.
- If Auto is selected, deselect Auto. This changes the I/O entitled memory mode to the manual mode.
- In the I/O Entitled Memory field, enter the total amount of I/O entitled memory that you want to assign to the shared memory partition. You can enter the size in a combination of gigabytes (GB) plus megabytes (MB).
- Adjust the settings in the Options area if necessary. You might need to increase the value in the Timeout (minutes) field to allow enough time for the HMC to complete the operation. (These settings relate to how the managed system adds memory dynamically. These settings are not retained after the addition completes.
- Click OK. If there is not enough physical memory in the shared memory pool by which to increase the I/O entitled memory to the amount specified in step 6, the Release Memory Resources window is displayed.
- Select shared memory partitions that are shut down until the available memory is equal to or greater than the requested memory and click OK.
