EVC vs CPU masking

[dirtdevil01]

Whats the diff between EVC and CPU masking? Don't they do the same thing? The doc mentions how EVC is used in clusters and you can use a selected baseline but in general it just masks the cpus features which is pretty much cpu masking.

[Troy_Clavell]

Yes, EVC sets a common baseline for your ESX Hosts in order to be vMotion compatible.  So, yes, at a high level, the accomplish the same thing.

[dirtdevil01]

Is EVC requried to be on in a cluster in order to vmotion?

[Troy_Clavell]

dirtdevil01 wrote:

Is EVC requried to be on in a cluster in order to vmotion?

EVC is only needed if you have incompatible CPU's on your ESX Hosts.  So, no, it's not required for vMotion to work.

[jmounts]

In my opionin EVC is better then masking, as its done by Family and applies to the entire cluster to make vMotion compatible with different server platforms.

However, EVC is not required to make vMotion work, UNLESS you are running different CPU classes in the same cluster.

CPU masking gives you alot more control, if you wanted you can strip down CPU masking enough to migrate between AMD and Intel CPUs, hot. But you lose alot of compatability in the VM's doing so. And this is not recommended 🙂

I do not remember if CPU masking can be done on the cluster like EVC can.

[Troy_Clavell]

...CPU masking enough to migrate between AMD and Intel CPUs

I have never seen nor heard of such a thing.  Can you provide an example?

[jmounts]

yes I can, but im not going to.

Unless your Guests are built for it, or you 100% absolultly know what you are doing you will crash your VMs after the migration from one vendor to another.

And I will not be responsible for someone crashing their environment testing this out.

[Troy_Clavell]

just my opinion, so take it for what it's worth.  vMotion between different vendors (AMD and Intel) is not supported (and from what I seen, doesn't work, period) should not be offered up as a viable solution.

You should NOT mix CPU vendors.

[jmounts · Accepted solution]

Until AMD and Intel streamline their feature sets so vmotion works out of the box. its not a viable solution. I dont think anyone here is disputing that fact.

I gave information on cpu masking against AMD and Intel as an example to show how powerful it is, and why EVC should be considered over CPU masking unless you need something special.