Use increased Micro-Partitioning limits on a Power system running Linux

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Micro-Partitioning allows for multiple partitions to share one physical processor. Previously, each partition was limited to 10 partitions per physical processor. On some newer Power systems running Linux, the Micro-partitioning limit is increased to 20 partitions per physical processor. Stated another way, this means that the minimum number of processing units that you can have for each virtual processor is now lowered to 0.05 (or 20 virtual processors for every processing unit).


In order to use 20 partitions per physical processor, ensure that you have the following hardware and software installed:

Hardware and Firmware Prerequisites

The increased partition limit applies on the following systems:

  • 9117-MMD (IBM Power 770), firmware level 760 or later
  • 9179-MHD (IBM Power 780), firmware level 760 or later
  • 9119-FHB (IBM Power 795), firmware level 760 or later

To update your firmware, see Getting firmware fixes.


Software Prerequisites

One of the following Linux distribution versions:

  • SUSE Linux Enterprise Server 11 SP2 or later
  • Red Hat Enterprise Linux 6.3 or later



After you've ensured that you've met the pre-requisites, follow these steps:

  1. Update your Linux distribution, if necessary.

    - For Red Hat Enterprise Linux 6.4  or SLES 11 SP3 (or later), no updates are necessary. The base kernels ship with the increased Micro-Partitioning limit included.

    - For Red Hat Enterprise Linux 6.3, update the kernel RPM to kernel-2.6.32-279.14.1.el6.ppc64.rpm or later. For more information see the security and bug fix update errata in the Red Hat Customer Portal.

    - For SLES, update SUSE Linux Enterprise Server 11 SP2 to kernel RPM version 3.0.42-0.7.3 or later. For more information, see the patch powerpc/pseries: Support lower minimum entitlement for virtual processors (bnc#775984) on the Linux kernel downloads page.

  2. Select the partition profile to change

    - If you are using the Hardware Management Console (HMC), see Changing partition profile properties for detailed steps.

    - If you are using the Integrated Virtualization Manager (IVM), see Modifying partition properties for detailed steps.

  3. Specify a lower value for the memory allocation for the partition. The minimum value that you can specify is .05 processor units.