Configuration requirements for shared memory

Review the requirements for the system, Virtual I/O Server (VIOS), logical partitions, and paging space devices so that you can successfully configure shared memory.

System requirements

The server must be a POWER6® processor-based server.
The server firmware must be at release 3.4.2, or later.
The Hardware Management Console (HMC) must be at version 7 release 3.4.2, or later.
The Integrated Virtualization Manager must be at version 2.1.1, or later.
The PowerVM® Active Memory Sharing technology must be activated. 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.

Paging VIOS partition requirements

VIOS partitions that provide access to the paging space devices for the shared memory partitions that are assigned to the shared memory pool (hereafter referred to as paging VIOS partitions) cannot use shared memory. Paging VIOS partitions must use dedicated memory.
Paging VIOS partitions must be at version 2.1.1, or later.
On IVM-managed systems, all logical partitions that use shared memory (hereafter referred to as shared memory partitions) must use virtual resources provided by the management partition.
On HMC-managed systems, consider configuring separate VIOS partitions as server partitions and paging VIOS partitions. For example, configure one VIOS partition to provide virtual resources to the shared memory partitions. Then, configure another VIOS partition as a paging VIOS partition.
On HMC-managed systems, you can configure multiple VIOS partitions to provide access to paging space devices. However, you can only assign up to two of those VIOS partitions to the shared memory pool at any given time.

Requirements for shared memory partitions

Shared memory partitions must use shared processors.
You can assign only virtual adapters to shared memory partitions. This means that you can dynamically add only virtual adapters to shared memory partitions. More specifically, you can assign only virtual SCSI client adapters, virtual Ethernet adapters, virtual fibre channel client adapters, and virtual serial adapters to AIX® and Linux shared memory partitions. You can assign only virtual SCSI client adapters, virtual Ethernet adapters, and virtual serial server adapters to IBM® i shared memory partitions. You cannot assign Host Ethernet Adapters (HEA) or host connection adapters (HCA) to shared memory partitions.
Shared memory partitions cannot use the barrier synchronization register.
Shared memory partitions cannot use huge pages.
AIX must be at version 6.1 Technology Level 3, or later, to run in a shared memory partition.
IBM i must be at version 6 release 1 with PTF SI32798 to run in a shared memory partition.
SUSE Linux Enterprise Server must be at version 11, or later, to run in a shared memory partition.
You cannot configure IBM i logical partitions that provide virtual resources to other logical partitions as shared memory partitions. Logical partitions that provide virtual resources to other logical partitions in a shared memory environment must be VIOS partitions.

Requirements for paging space devices

The paging space devices for AIX or Linux shared memory partitions must be at least the size of the maximum logical memory of the shared memory partition.
The paging space devices for IBM i shared memory partitions must be at least the size of the maximum logical memory of the shared memory partition plus 8 KB for every megabyte. For example, if the maximum logical memory of the shared memory partition is 16 GB, its paging space device must be at least 16.125 GB.
Paging space devices can only be assigned to one shared memory pool at a time. You cannot assign the same paging space device to a shared memory pool on one system and to another shared memory pool on another system at the same time.
Paging space devices that are accessed by a single paging VIOS partition must meet the following requirements:
- They can be physical or logical volumes.
- They can be located in physical storage on the server or on a storage area network (SAN).
Paging space devices that are accessed redundantly by two paging VIOS partitions must meet the following requirements:
- They must be physical volumes.
- They must be located on a SAN.
- They must be configured with global IDs.
- They must be accessible to both paging VIOS partitions.
- The reserve attribute must be set to no reserve. (The VIOS automatically sets the reserve attribute to no reserve when you add the paging space device to the shared memory pool.)
Physical volumes that are configured as paging space devices cannot belong to a volume group, such as the rootvg volume group.
Logical volumes that are configured as paging space devices must be located in a volume group that is dedicated for paging space devices.
Paging space devices must be available. You cannot use the physical volume or logical volume as a paging space device if it is already configured as a paging space device or virtual disk for another logical partition.
Paging space devices cannot be used to boot a logical partition.
After you assign a paging space device to the shared memory pool, you must manage the device by using one of the following tools:
- The Create/Modify Shared Memory Pool wizard on the HMC.
- The View/Modify Shared Memory Pool page on the Integrated Virtualization Manager.
Do not change or remove the device using other management tools.

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Last updated: Thu, June 12, 2014