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VMotion CPU Compatibility, PERF_MSR Extended-Feature Bit, and Intel Dempsey (and subsequent) Processors

Details

Dempsey (and subsequent) Intel processors have bit 15 (PERF_MSR) set in their extended features. For VMotion to occur between Dempsey (or other servers based on Intel Pentium 4 family 15, model 6, such as Pressler, Cedar Mill, and Tulsa), or between servers with older Xeon processors, VirtualCenter Server must ignore bit 15.

 
Note: Only ESX Server 2.5.4 (and later releases) support Dempsey processors.

Solution

By design, the default bit mask (CPU compatibility for VMotion) provided with VirtualCenter Server 1.3.1 Patch 2, VirtualCenter 1.4.1, and later versions of VirtualCenter Server software disregards the PERF_MSR bit (introduced by Intel in Dempsey and subsequent processors). However, for VirtualCenter Server releases prior to VirtualCenter Server 1.3.1 Patch 2, you must manually configure a bit-mask (as detailed below) to ignore this bit and support VMotion between systems running on the Dempsey (and subsequent) processor.
 
 
To determine if a particular system has Dempsey processors:
  1. Run the following command:

    cat /proc/vmware/cpuinfo

  2. The command returns the following information for a Dempsey processor:

    family = 15
    model = 6
    extFeat = 0x0000e43d
If the system has Dempsey processors, you must manually configure the mask:
  1. Locate the VirtualCenter configuration file, config.ini (usually located at C:\Documents and Settings\All Users\Application Data\VMware\VMware VirtualCenter).

  2. If the config.ini file does not exist, create a text file and save it with that name.

  3. Add the following line to the file:

    migrate.ignore.extfeature.bits = 0xE5A0

  4. Restart the VirtualCenter management server.

 

Keywords

esx254; vmotion; dempsey;Pressler; Cedar Mill; Tulsa; vmotion constraints and CPU extended features; masking constraints;

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  • KB Article: 4893083
  • Updated: Aug 14, 2009
  • Products:
    VMware ESX
    VMware VirtualCenter
  • Product Versions:
    VMware VirtualCenter 1.1.x
    VMware VirtualCenter 1.2.x
    VMware VirtualCenter 1.3.x
    VMware VirtualCenter 1.4.x