I've got a question about EVC.
I want to add 1 server with an Intel Xeon X5450 to a vmware vsphere 4 update 1 farm
The servers that are currently in the farm all have an Intel Xeon E5420 .
My question is, can i just add the server and use vmotion?
I do not know if I need to use EVC because they are in the same family according to this document.
Or can I just add the server and enjoy vmotion etc.
If the current cluster already has VM's running in it, and you need to enable EVC, it can be done on hosts with running guests. What I would do is add the host into the existing cluster and attempt a vMotion. You'll know pretty quick whether or not it's vMotion Compatible.
With that said, and not really answering your question. I see no reason to EVER NOT enable vMotion on all clusters. It has no impact on performance in could safe you some headaches in the future.
Depending on the version of vSphere you can enable EVC also on a running cluster.
Otherwise you must chech the correct common baseline, buind a new EVC cluster, put the new host on it, use vMotion across clusters, free the other node, and then move in the new cluster.