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vMotion CPU compatibility requirements for Intel processors (1991)

Details

This article outlines migrating virtual machines with vMotion across Intel processors, and the necessary steps to take to ensure compatibility.


Solution

In ESX 3.5 Update 2 and later, VMware recommends using Enhanced vMotion Compatibility (EVC) to eliminate many vMotion CPU compatibility problems. For more information on EVC, see Enhanced vMotion Compatibility (EVC) processor support (1003212).
 
To ensure system stability during migration with vMotion, VirtualCenter and vCenter Server require the source and target CPUs to be compatible. For more information on CPU compatibility requirements, see Basic System Administration for your version of vCenter Server or VirtualCenter, available from http://www.vmware.com/support/pubs/.

If the source and target CPUs are incompatible for vMotion, you can:

  • Perform a cold migration (rather than a vMotion migration), thereby removing vMotion CPU requirements as an issue.
  • Remove vMotion compatibility constraints by modifying the default bit-mask used by vCenter Server or VirtualCenter.

    Note: That some modifications discussed in this knowledge base article are neither supported nor recommended by VMware for production environments. In general, masking any CPU features intended for applications (such as SSE3) is not supported for vMotion . Use of EVC is recommended for migrating virtual machines across CPU generations.

To obtain more information about a host system's CPU, you can use the CPU Identification Utility. VMware provides this as an ISO image file that can be uncompressed and used to create a bootable CD-ROM that provides CPU information about a host, even before an operating system or ESX/ESXi is installed. The latest version of this tool can be found on the VMware downloads page at http://vmware.com/download/shared_utilities.html.

This knowledge base article discusses vMotion compatibility constraints for Intel CPUs. For detailed information about how to apply the masks discussed in this article, see vMotion CPU Compatibility - Migrations Prevented Due to CPU Mismatch - How to Override Masks (1993). For information on AMD CPUs, see VMotion CPU Compatibility Requirements for AMD Processors (1992).

vMotion Compatibility Groups for Intel Processors

To guarantee successful migrations with vMotion, VMware has defined several compatibility groups based on processor family (Pentium 4, Core) and features introduced within those families.

By default, vCenter Server and VirtualCenter support vMotion migrations within each CPU compatibility group. For example, migration within group A is allowed, but migration from group A to group B or from group B to group C is not, as shown in the tables.

 
Intel Pentium CPUs
 
vMotion CPU Compatibility Group CPU Details

 

ESX Server 3.x and ESX 4.x

 

ESX Server 2.x

 
 
 
 
 
 
 
 
Group A
Without SSE3, without XD (eXecute Disable).
Models include:
  • Intel P4s prior to Model 3, Stepping 1. For example, Willamette and Northwood.
  • Xeon and Xeon MP CPUs prior to Nocona, Q3 2004. For example, Foster, Prestonia, and Gallatin.
 
 
 
For A <-> B vMotion, apply SSE3 mask. (Not supported)




 

 

 

 

 

 

For A <-> B vMotion, apply SSE3 mask. (Not supported)

 

 
 
 
 
 
Group B
(Group B and C are the same for VC 1.x)

 

With SSE3, without XD.
Models include:
 
P4s from Model 3, Stepping 1 to Model 4, Stepping 1.
 
For example, Prescott, or numbered 5x0, 5x5, 5x9.

 

 
 
 
 
 
For B <-> C vMotion, apply NX mask.(Supported)


 

 
 
 
 
 
 
 
 
Group C
(Group B and C are the same for VC 1.x)

 

With SSE3 and XD.
Models include:
 
P4s after Model 4, Stepping 1 onward and Xeon and Xeon MP with 64-bit (EM64T) enabled.
 
For example, Irwindale, Cranford, Dempsey, Tulsa, or numbered 50xx, 70xx, or 71xx.

Intel Core CPUs

vMotion CPU Compatibility Group
CPU Details
ESXi 5.0, ESX/ESXi 4.x, ESX Server 3.x, and ESX Server 2.x
Group A
Without SSSE3, SSE4.1, SSE4.2 or AES.
Models include:
Dual-core Xeon LV based on Intel Core microarchitecture.
For example, Sossaman.
For A<->B vMotion, apply SSSE3 mask. (Not supported)
Group B
With SSSE3 only.
Models include:
Intel Xeon CPUs based on the Intel Core microarchitecture. For example, Intel Xeon 30xx, 32xx, 51xx, 53xx, 72xx, or 73xx.
For B<->C vMotion, apply SSE4.1 mask. (Not supported prior to ESX 3.5. Experimentally supported for ESX 3.5 and later only.)
Group C
With SSSE 3 and SSE4.1 only.
Models include:
Intel Xeon CPUs based on 45nm Intel Core microarchitecture. For example, Intel Xeon 31xx, 33xx, 52xx, 54xx, or 74xx.
For C<->D vMotion, apply SSE4.2 mask. (Not supported prior to ESX 3.5. Experimentally supported for ESX 3.5 and later only.)
Group D
With SSSE3, SSE4.1, and SSE4.2 only.
Models include:
Intel Xeon CPUs based on Intel Nehalem microarchitecture. For example, Intel Xeon 75xx Series, Intel Xeon 65xx Series, Intel Xeon 55xx Series ("Nehalem-EP"), and Intel Xeon 34xx Series ("Lynnfield").
For D<->E vMotion, apply AES mask. (Not supported prior to ESX 3.5. Experimentally supported for ESX 3.5 and later only.)
Group E
With SSSE3, SSE4.1, SSE4.2, and AES.
Models include:
Intel Xeon CPUs based on Intel Westmere microarchitecture. For example, Intel Xeon 56xx Series ("Westmere-EP").

Applying the Masks

For information about how to apply masks referenced in the tables, see Modifying the Default Mask in vMotion CPU Compatibility - Migrations Prevented Due to CPU Mismatch - How to Override Masks (1993).
 
Warning: For production environments, VMware neither supports nor recommends modifying CPU masks for SSE3, SSSE3, SSE4.1, or SSE4.2, because of the risk of failure in applications or the guest operating system after migration. Experimental support is available for some masks in ESX 3.5 and later as noted. For more information on experimental feature support, see http://www.vmware.com/support/policies/experimental.html.

vMotion Between Single-Core and Multi-Core Processors

Migrations between single-core and multi-core Intel processors are supported, as long as the source and target CPUs have compatible CPU features (or the features are masked) as outlined in the tables above.

For More Information

For more information about the Intel Pentium 4 CPU family, see http://www.intel.com/support/processors/pentium4/.
For more information about Intel Xeon processors, see http://support.intel.com/support/processors/xeon/.
For more information about SSE3, SSSE3, and SSE4, see the Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 1: Basic Architecture: http://www.intel.com/products/processor/manuals/
 
Note: Knowledge base articles 1991, 1992, and 1993 replace KB article 1377.
 
 
Additional Information:
 
For translated versions of this article, see:

Tags

cannot-vmotion different-intel-cpu incompatible-cpu migrate-vm-across-esx-hosts multi-core single-core unable-to-migrate-vm vmotion-vm

Keywords

URLZ; KB; 1991; dual core; dualcore

Update History

06/21/2012 - Updated for 5.x, minor formatting changes

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