Enhanced VMotion Compatibility(EVC) question

[tlyczko]

I know this is a new VMotion feature which solves some of the problems of processor incompatibilities.

We are getting a second VMware host, into which I can put either an Intel Xeon 53xx or 54xx quad-core processor.

Our 1st host has a Xeon 5150 dual-core processor, which I may get upgraded to a Xeon 53xx processor.

Would EVC make it at least reasonably possible to VMottion from the 54xx to either the 5150 or 53xx processor??

If VMotion failed even with EVC turned on, would the VM be totally destroyed and unusable or unavailable on both VMs or just on the receiving VM??

Thank you, Tom

[RParker]

Our 1st host has a Xeon 5150 dual-core processor, which I may get upgraded to a Xeon 53xx processor. Would EVC make it at least reasonably possible to VMottion from the 54xx to either the 5150 or 53xx processor??

Nope, this is the type of thing it guards against.

Would EVC make it at least reasonably possible to VMottion from the 54xx to either the 5150 or 53xx processor??

Nope. It won't even let you add the host to the cluster.

For your case it's best to leave EVC off, until you get ALL your ESX hosts with the SAME CPU match... That's what its for, to prevent incompatible CPU hosts with dissimilar vmotion options from being in the same cluster. Nothing will happen to your VM's, they just won't be able to utilize vmotion, and probably not cold migration either. You have to remove them from inventory, and add them to the other host.

[tlyczko]

Ouch!! I have a lot to learn, then.

My interpretation was that EVC makes it easier to VMotion between processors with relatively differences like the 51xx series and the 53xx sereis (as opposed to the difference between Intel/AMD), similar to what the relatively unsupported masking procedures do...hide the incompatible features.

I will proceed with your remarks in mind...It may be quite some time before we get a 3rd host so this makes things pretty complicated.

However the 5150 box is upgradeable to the 53xx quad-core, which is still available -- I can at least do that, money permitting...if not, the 51xx and 53xx are indeed VMotion-compatible.

Thank you, Tom

[stvkpln]

To clear the air, clear up any confusion, etc... Here's the official stance on what EVC is (direct from the KB article on the subject!): Enhanced VMotion Compatibility (EVC) simplifies VMotion compatibility issues across CPU generations. EVC automatically configures server CPUs with Intel FlexMigration or AMD-V Extended Migration technologies to be compatible with older servers. After EVC is enabled for a cluster in the VirtualCenter inventory, all hosts in that cluster are configured to present identical CPU features and ensure CPU compatibility for VMotion. The features presented by each host are determined by selecting a predefined EVC baseline. VirtualCenter does not permit the addition of hosts that cannot be automatically configured to be compatible with the EVC baseline.

Based on the kb article (tinyurl: ), the 51xx series and 54xx are both EVC-compatible, so if you create a new cluster and enable EVC, then migrate your VM's into that cluster, you should be good going between the two of them with VMotion, etc... Just make sure you enable VT and the Intel eXecute Disable in the system BIOS.

[tlyczko]

Thank you, dizorted.

I will have only 1 cluster, so when I can get VI3 Ent and set up VMotion etc., it's a matter of shutting down the VMs and turning on this feature.

The 51xx and 53xx series are already compatible, I know. I had hoped this would make a 51xx/53xx Xeon VMotion-able with a Xeon 54xx.

Thank you,

Tom

[SuryaVMware]

I agree with diztorted. If not there is no point in calling it Enhanced VMotion ..

More information on this is available

http://compare.intel.com/PCC/default.aspx?familyid=5&culture=en-US

http://developers.amd.com/assets/Live%20Virtual%20Machine%20Migration%20on%20AMD%20processors.pdf

http://www.virtualization.info/2007/09/intel-releases-flexmigration-in-new.html

http://www.virtualization.info/2007/09/amd-to-simplify-v2v-with-amd-v-extended.html

and search youtube for flex Migration you will see some nice videos from Intel and VMware.

-Surya

[stvkpln]

Yep. If you can take the downtime, just shut the VM's down, enable EVC, and you're good. the 51xx, 53xx, and 54xx are all supported by EVC, as the KB article lists.

[prashantprahlad]

EVC will make Intel 45nm Core2 based (Penryn) processors compatible with Intel Core2 based (Merom) processors. Similarly, AMD's Third Generation Opteron will be compatible with their older generation.

The VMware KB article 1003212 lists the CPU models that are compatible EVC requires that VMs to be evacuated or powered off when being enabled. I'm sure many are awareof ways to do this without having to force all your VMs to shutdown.