VMotion fails with imcompatible CPUs error (1993) But CPUs are the same

[VanAlex]

Hi,

I have a vSphere Cluster with two similar dell servers, VMotion migration has been working correctly, but since yesterday it fails with a message stating the CPUs are imcompatible, but the CPUs are exactly the same. This is clearly an error or Bug with VMware. Any thougths on how to solve this SERIOUS issue?

[VMmatty]

It sounds like something in the configuration changed if it was working previously and now it is not. Check out the following two KBs which talk about VMotion between CPUs that are not identical. Maybe your issue can be solved by something in here.

VMotion compatability with Intel CPUs: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1991

How to override CPU masks: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1993

[VanAlex]

The only thing that changed recently was the installation/configuration of the VMware disaster recovery plugin. Everything else is exactly the same, and the CPUs are identical. I saw those KBs before deciding to post this issue... The CPUs are absolutely identical.

[vmkarthik]

what is the version of esx and vcenter you have?

If you have vcenter 2.5 update 2, have you enabled the EVC option and tried vmotioning??

[VanAlex]

ESX 4, vCenter 4 build 162856.

EVC was disabled, I enabled it but I still get the same error. Still, from what I understood I shouldn't need EVC with similar CPUs.

I'm restarting both hosts with EVC enabled, and rebooting all VMs. Let's see if that makes a difference.

[VanAlex]

Even after rebooting all machines (VM and Physical), the problem persists...

This is a cluster with only 2 Dells (Model for Virtualization PowerEdge 1950 Intel E5405)... vmotion worked perfectly with Infrastructure 3, and also perfectly after upgrading to vSphere 4. Can't really what might have change to cause this. The hardware has been untouched.

[VMmatty]

This seems highly unlikely but is it possible that someone disabled Intel-VT in the BIOS on one of the servers? I'm not sure if that alone would cause the problem either.

At this point you should probably start looking through the logs to see if you can get any more info on why it's failing. Have you checked out the vmkernel log? That is where I would start.

[probie]

I suppose you upgraded the virtual machine hardware? We had the same issue. Workaround: power off VM, Edit Settings, CPU ID Mask - Advanced, Reset all to default and save, then start the VM again, problem should be gone.

[VanAlex]

Thank you!!!... This was driving me crazy, specially without having time to diagnose the issue.