Can't vMotion 6.7U3 to 6.7U2. (with EVC error)

[hoon0715]

Hi, all.

I use ESXi 6.7U2 (Build.13006603) and 6.7U3 (Build.17167734) in the same cluster.

But the CPU of all servers is Skylake.

I found that VMs running on 6.7U3 can not be migrated to 6.7U2 with the error message below.

The target host does not support the virtual machine's current hardware requirements.
Use a cluster with enhanced vmotion compatibility (evc) enabled to create a uniform set of cpu features across the cluster, or use per-vm evc for a consistent set of cpu features for a virtual machine and allow the virtual machine to be moved to a host capable of supporting that set of cpu features. See KB 1003212 for cluster EVC information. com.vmware.vim.vmfeature.cpuid.mdclear

VMs running on 6.7U2 are free to migrate anywhere.

I've never turned on the EVC mode, and the CPU class is all the same, but why does the EVC problem occur??

Thanks in advanced.

[a_p_]

This could be related to a CPU feature that Intel introduced in Skylake, but removed in later CPU generations.
For details, see e.g. https://kb.vmware.com/s/article/76155

André

[hoon0715]

Thanks for your reply.

Then, should I understand that there is a new feature of the Skylake CPU that can only be used in 6.7U3?

[a_p_]

It's a feature that was introduced with Skylake, but removed again in later CPU generations. So it should basically not be used at all anymore in order to allow vMotion. From how I understand the KB, it's not exposed for VMs with either HW version less than 13, or with EVC being enabled.

CPU features are exposed to VMs at power on, so it basically depends on the ESXi build, the VM's virtual hardware version, and whether EVC is enabled, which CPU features the VM uses.

André