Raising the EVC mode of a cluster

[terrible_towel]

Hi all.   We’ve gone through a few hardware cycles.  Building a new cluster with new HW and then vmotioning the VMs into it.

Since we didn’t take the time to power cycle/uplift the EVC mode at that time.. we now have a cluster with an old EVC mode. One that will not support RHEL10 down the line.   So we need to get it done.   Our actual HW will support up through Skylake, but our EVC mode is back on Ivy Bridge.

Can per VM EVC only be set to something lower than the cluster it resides on?  I’ve tried powering off a VM, setting the per VM EVC mode to SkyLake, but then I can not power it on in this cluster.

I can not power off all VMs at the same time to do this (700 VMs).   Is my only other option to build a new cluster with higher EVC mode, and then power off VMs to move it into the new cluster?

Thanks.

[Alexandru Capras]

https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/8-0/change-the-evc-mode-for-a-cluster.html

Documentation says that you can raise the EVC mode and the running virtual machine can remain powered on. New EVC mode features will not be available to the VMs until they are powered off and powered back on again.

Never done this in production so I did this test in my lab and I raised the EVC mode from Ivy Bridge to a newer mode while the test machine remained on. The other way around is the tricky part, if you lower the EVC mode you have to power off the VMs before.

Since you said that you have 700 VMs in the cluster you can plan phased power cycles.
Check the link above there's a tip where you can configure the VM to power cycle when its guest OS is rebooted - so maybe you can do that when the patch window/maintenance is scheduled.