vMotion and EVC

[pan1268]

Hello Experts,

Please help me to find out if we need to enable evc for vMotion to work in a cluster where I have Intel 6140 esxi hosts and I will add Intel 8260 new hosts.

Cheers

[pkvmw]

Hi,

Enable EVC by doing:
1. Shutting down all VMs in this cluster
2. Enabling EVC in the cluster settings
3. Startup all VMs and add new hosts

Regards,
Patrik

[scott28tt · Accepted solution]

To migrate between the current hosts and new hosts, yes you will.

6140 is Skylake, 8260 is Cascade Lake, so you'll need EVC in Skylake mode.

[pan1268]

Hi Scott,

Appreciate your help and sincere apologies for responding late on the thread.  I have a follow up Q please.  Can we enable EVC with Skylake mode  on the in the cluster where I have only 6140 ESXI hosts without powering down any VMs. 

Also, Can we migrate VM from EVC disabled cluster (that is on old 6140 ESXI hosts ) to new EVC enabled cluster ( that is on 8260 ESXI hosts ) .  On the new cluster with 8260 model we will enable EVC with Skylate option. For example - when i create a new cluster with 8260 model - I will create it with skylake option and then vMotion migrate the VMs from old cluster ( 6140 ESXI hosts ) to new cluster. Storage is shared between the two cluster. 

Cheers

[IRIX201110141]

If you have a EVC Mode which is a direct match to your current Host pCPUs that you can enable it always with running VMs.

Regards,
Joerg

[a_p_ · Accepted solution]

Enabling, disabling, or modifying the EVC mode does not effect any powered on VMs.
A given EVC mode can however only be set if the physical hardware (CPU) supports it, and if no powered on VM has CPU features in use which are not supported for the given EVC mode.

Since CPU features are exposed to VMs only at power on, you can migrate VMs between ESXi hosts with the same, or newer CPUs (given it supports the exposed features) even without EVC being enabled.

That said, there's an issue with Skylake CPUs for which Intel introduced a new CPU feature, that they dropped again in later CPU models (see e.g. https://kb.vmware.com/s/article/76155 for details). Depending on the ESXi version/build on which a VM has been powered on, and the VM's virtual hardware version, you may need to shut down that VM in order to migrate it to the new EVC enabled cluster.

André