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MrBigFeathas
Enthusiast
Enthusiast

Enabling EVC Mode on existing ESXi 4.0 u1 cluster

I had a question about enabling EVC mode on an existing cluster. I currently have 3 machines that are all compatible with each other. I can vMotion between them without EVC enabled. The CPUs are all from the Nehalem family. I am going to be adding a new server to the cluster that that has a Westmere CPU. I know I need to enable EVC for vMotion to work with the new Host. My question is, since the 3 hosts are currently using the same CPU series can i just enable EVC mode now without any downtime or issues? it says validation succeeded when I select the Intel Xeon Core i7 (Nehalem) on the EVC setting.

Thanks

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Troy_Clavell
Immortal
Immortal

one thing to consider, is you cannot enable EVC on a cluster with VM's running.  So, I would create a new Cluster, enable EVC, add new host, find your EVC Baseline.  From there you should be able to vmotion to the new cluster, once the hosts from the other cluster are empty of any guests, disconnect and drag host to new cluster.

If you plan on shutting down all your guests, well, than you won't have to create a new cluster.

see below for baselines

http://kb.vmware.com/kb/1003212

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MrBigFeathas
Enthusiast
Enthusiast

So, even if the 3 current hosts are the same I can't enable EVC mode with the VMs running? I don't have the 4th host yet. I was under the impression that I could enable it on the fly as long as all the machines were from the same series CPU.

Glad I asked first.

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Troy_Clavell
Immortal
Immortal

The only way to enable EVC on a Cluster is to have the VM's powered off, or the ESX(i) Hosts empty of any guests. I would wait until you get the fourth host, this way you will be able to determine your EVC Mode, then create your EVC Cluster.

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MrBigFeathas
Enthusiast
Enthusiast

I just found this post after searching.

http://communities.vmware.com/thread/281618

Does that mean the answer given here is wrong?

">1. Is it correct that if a cluster is already existing and running many VMs I would have to either power them off or move them to enable EVC?

All running VMs must be on host with oldest CPUs equal to EVC level. For. ex if you have cluster with 53xx and 54xx Xeons then you can enable Core2 EVC level when all running VMs are on 53xx CPUs and not on 54xx."

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Dave_Mishchenko
Immortal
Immortal

Enabling EVC changes the feature set of the vCPUs that the VMs are using hence the need to power down all running VMs first.

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idle-jam
Immortal
Immortal

yes you're right. you will need to power off as suggested above. however if you have enough hosts, there are some tricks here: http://malaysiavm.com/blog/how-to-enable-evc-on-esx-35/

although it's for ESX3,5 it works well for ESX/ESXi 4 too.

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