VMware VMotion fails with "CPU is incompatible" error - IBM Servers

Resolving The Problem

Source

RETAIN tip: H201978

Symptom

Issue 1:

When attempting to use VMotion between two (2) identical servers, the VMotion fails and VMware reports the following error:

Issue 2:

When using a VMware cluster with EVC enabled in a VCenter server, it is not possible to add a server with Westmere processors to a cluster with the "Intel Xeon 32nm Core i7 ("Westmere")" EVC option selected.

Affected configurations

The system may be any of the following IBM servers:

• BladeCenter HS22, type 1936, any model
• BladeCenter HS22, type 7870, any model
• BladeCenter HS22V, type 1949, any model
• BladeCenter HS22V, type 7871, any model
• BladeCenter HX5, type 7872, any model
• System x3550 M2, type 4198, any model
• System x3550 M2, type 7946, any model
• System x3550 M3, type 4254, any model
• System x3550 M3, type 7944, any model
• System x3650 M2, type 4199, any model
• System x3650 M2, type 7947, any model
• System x3650 M3, type 4255, any model
• System x3650 M3, type 7945, any model

This tip is not software specific.
This tip is not option specific.

Workaround

The default value of the Advanced Encryption Standard (AES) feature is "Enabled" in Unified Extensible Firmware Interface (UEFI) version 1.10 and newer. The default value was disabled in previous versions. The setting must be consistent across two (2) blades to VMotion between them.

The value may need to be set to "Disabled" when using VMotion depending on the processors you are using. See VMware for further detail on whether or not AES should be enabled or disabled for your environment:

To disable AES:

1. Download the Advanced Settings Utility (ASU) utility, version 3.62 (or later) from the following URL:
   
   

   http://www.ibm.com/support/entry/portal/docdisplay?lndocid=TOOL-ASU

   
   
2. Run the following ASU command:
   
   

   asu set UEFI.AesEnable Disable

   
   
3. Reboot the server.
   

To enable AES:

• Install UEFI version 1.10 or newer and restore the default settings in UEFI.

Additional information

In order for a VMotion migration to succeed between two (2) processors, the virtual machine must view them as identical. If the AES setting is mixed across blades, then performing a migration between them will fail.

VMware's EVC function serves to mask the differences between processors. EVC expects processors to have AES enabled if they are going to run in "Westmere" EVC mode. If the processors do not support AES or if the server is configured with AES disabled, then you cannot select "Westmere" EVC mode.