Vmotion Enhanced Compatibility: Anyone using it?

[jbsengineer]

From what I am reading on the Intel website the 45nm Quad-core 5400 series processors support the "Flex Migration". I understand this to be able to hide specific features of the processor at the hardware level thus enabling Vmotion migration between older and newer processors. Is this currently supported in ESX 3.5? If so is anyone successfully using it? We are looking at upgrading 4 of our Poweredge's to the newer 2950's with Quad-core's and I would like not to create another cluster.

Thanks.

[dmorgan]

I cannot definitively say that this is not supported in VMWare, however I am using 3.5 with current patches, and can definitively say that it does not let you VMotion between non-compatible processors. I would extrapolate from this, and the fact that VMWare is still using their compatibility matrix to determine which processors are vmotion-able, that this is not possible with the current release of VMWare.

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[jbsengineer]

This feature would require the processor to have the Intel's Flex Migration hardware support. Do you have one of the supported Procs? There are only 2 series from Intel that I can see. Then there would be some sort of intervention on the BIOS or ESX Host side to mask the feature set of the processor.

From VMware's Vmotion Info Guide:

"Q: What is Enhanced VMotion Compatibility?

A: Hardware Support for Live Migration (Flex Migration from Intel and Extended Migration from AMD) allows the virtualization layer to support masking out CPUID features. This prevents applications from using these features, thereby allowing VMotion across a broader range of CPUs while maintaining application and guest OS stability.

Q: Does Enhanced VMotion Compatibility mean VMotion between any CPUs becomes possible?

Frequently Asked Questions 16

VMware VMware VMotion Information Guide

Frequently Asked Questions 17

A: No. Enhanced VMotion uses hardware support to modify the supported CPU feature set reported by the CPUID instruction. Other incompatibilities outside the feature set, such as vendors, models, etc. would still exist and may cause CPU incompatibility for VMotion. For instance, Enhanced VMotion will never allow VMotion between Intel and AMD CPUs."

[dmorgan]

Yes, but either this functionality exists Outside of VMWare, or VMWare has to support it. Hardware Support for Live Migration (Flex Migration from Intel and Extended Migration from AMD) allows the virtualization layer to support masking out CPUID features.Hardware Support for Live Migration (Flex Migration from Intel and Extended Migration from AMD) allows the virtualization layer to support masking out CPUID features. This seems that they have laid the hardware foundation for Virtualization platforms to utilize this feature set, but that it would require VMWare to implement this. I haven't heard of anything, nor is there anything mentioned in the compatibility matrix, referencing this functionality at this time. Again, I am not the expert, I would like to hear from VMWare directly on this one.

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[jbsengineer]

I've been trying to dig up an article I read stating this would be supported in ESX 3.5. I can only find documentation in the VMotion guide unfortunately.

[avarcher]

Sounds like an extended version of the No eXecute flag masking we have now.