pervm_evcMode_powercli

[jvm2016]

Hi Luc ,

just thought of discussing the use case of per vm EVC on virtual machine .

if yu can review below statements .

1:these features are arranged from low priority (intel-merom) to  high priority (intel-skylake ) .

so in case of migrations of vms to different evc set (in different clusters or cloud environemt with diferent evc set )

we can enable it on per vm basis .

this will avoid changing the evc set at cluster level which involved reboot of the hosts .

[LucD]

Not too sure what the question is, but Kyle did a post on the cmdlets for EVC settings.

See Configuring Per-VM EVC with PowerCLI

[jvm2016]

Thanks Luc,

i am just trying to understand the use case of enabling per vm  evc mode .

if i need to migrate vm to a cluster which is configured for intel-haswell .do i need to enable vms with intel-haswell to get max capability of cpu feature sets.

[T180985]

If you havent set Per-VM EVC mode then the VM just picks up the EVC mode of the cluster so when you vMotion the VM to a cluster with a newer CPU, it will pick up the features of the new CPU.
If you have enabled Per-VM Sandy Bridge, when you vMotion the VM it will continue to use Sandy Bridge until you shut it down and change it to either use the cluster level or set it to Haswell

In terms of use case, this might be usefull for when you having to vMotion to enviroments with an older EVC mode or even allowing certain VMs to run at a higher (supported) level on a cluster that is set at an older level.

[LucD · Accepted solution]

How I understand it, and which the article I pointed to explains in the introduction, when you use per-VM EVC, it is primarily intended to allow you to move VMs across clusters, datacenters, vCenters and VMC.
When the VM is in a new location where the EVC level is above the one configured for the VM, you would indeed need to change the EVC setting of the VM to be able to use the features available in the newer/higher EVC level.
The drawback would be that your VM can't move back to an environment with the lower EVC level.

It's a consideration you as the administrator will have to make.

[jvm2016]

Thnaks Luc.

[jvm2016]

thnaks