POWER7 information

Configuring the shared memory pool

You can configure the size of the shared memory pool, assign paging space devices to the shared memory pool, and assign one or two Virtual I/O Server (VIOS) logical partitions (that provide access to the paging space devices) to the shared memory pool using the Hardware Management Console (HMC).

Before you start, complete the following tasks:

Enter the activation code for the PowerVM® Enterprise Edition. For instructions, see Entering the activation code for PowerVM Editions using the HMC version 7. The ability to share memory among multiple logical partitions is known as the PowerVM Active Memory™ Sharing technology. The PowerVM Active Memory Sharing technology is available with the PowerVM Enterprise Edition for which you must obtain and enter a PowerVM Editions activation code.
Ensure that your configuration meets the configuration requirements for shared memory. To review the requirements, see Configuration requirements for shared memory.
Complete the required preparation tasks. For instructions, see Preparing to configure shared memory.
Create the VIOS logical partitions (hereafter referred to as paging VIOS partitions) that you plan to assign to the shared memory pool, and then install the VIOS. For instructions, see Creating additional logical partitions and Installing the VIOS and client logical partitions.
Create and configure the paging space devices that are owned by the paging VIOS partitions that you plan to assign to the shared memory pool. If you plan to use logical volumes as paging space devices, then create the logical volumes. For instructions, see Creating a virtual disk for a VIOS logical partition using the HMC.
Verify that the HMC is at version 7 release 3.4.2, or later. For instructions, see Upgrading your HMC software.
Ensure that you are a super administrator or operator of the HMC.

If there is not enough physical memory available in the system to allocate to the shared memory pool, you can release to the hypervisor the physical memory that is currently assigned to logical partitions that use dedicated memory and that are shutdown. The hypervisor can then assign the released physical memory to the shared memory pool.

To configure the shared memory pool, complete the following steps using the HMC:

In the navigation pane, expand Systems Management and click Servers.
In the work pane, select the server on which you want to configure the shared memory pool.
From the Tasks menu, click Configuration > Virtual Resources > Shared Memory Pool Management. The Shared Memory Pool wizard is displayed.
Follow the steps in the Shared Memory Pool wizard to configure the shared memory pool.
Tip: If you expect to see a particular device on the list of eligible devices to add to the shared memory pool, but the device does not appear, you can run the prepdev command from the VIOS command line. You can run the prepdev command to determine why the device does not meet the requirements for paging space devices and to learn what tasks need to be performed on the device to satisfy the requirements.
If a device was used by a logical partition and then the logical partition was removed, the device might not meet the requirements for a paging space device, even though the logical partition was removed. The prepdev command detects this situation and provides instructions about how to change the device so that it meets the requirements for a paging space device.

After you create the shared memory pool, you can create logical partitions that use shared memory. For instructions, see Creating additional logical partitions.

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Last updated: Thu, September 20, 2018