Enabling EVC mode for production cluster

[kennyhwx]

Hi,

I have the following setup:

• Existing Cluster_A with 3 ESX hosts running on Intel Xeon E5540 CPU (Nahelem)
• 30 VMs is running in a production environment
• 2 new ESX hosts running on Intel Xeon E5649 CPU (Westmere)

The 2 new hosts are not added into vCenter yet but the goal is to allow the adding of these 2 new hosts into Cluster_A.

I understand that in order to have all 5 hosts in the same cluster, EVC mode must be enabled with the highest level being "Nahelem" (lowest common denominator).

From a theoretical point of view, any CPU masking to be applied is going to be identical to the existing CPU settings presented to the running VMs, thus enabling EVC using the same CPU architecture should not cause any conflict or problem.

Therefore, I would like to seek confimation that enabling EVC and setting it to Nahelem level for Cluster_A will not cause an impact (e.g. BSOD) or downtime to the VMs.

Thanks,

Kenny

[a_p_]

Welcome to the Community,

the most that can happen is that enabling EVC will not succeed. You can raise the EVC level without affecting the VM's, but you cannot lower it. I doubt you will be albe to enable EVC without powering off the VM's in the cluster though.

André

[kennyhwx]

Hi Andre,

Thanks.

If I choose a level lower or higher than Nahelem, it prompts me for incompatible VMs and requires me to shutdown or evacuate the VMs inside the cluster.

In addition, the "OK" button is greyed out.

However when choosing the Nahelem EVC level, the  compatibility shows "validation succeeded" and the "OK" button is  enabled. Thus, would like to find out if there are any "side effects" to VMs before applying.

Kenny

[arturka · Accepted solution]

Therefore, I would like to seek confimation that enabling EVC and setting it to Nahelem level for Cluster_A will not cause an impact (e.g. BSOD) or downtime to the VMs.Kenny

Hi

Is 100% safe operation (did it many, many times on running clusters). No side effects 🙂

1. create TEST VM
2. add new ESX server into vCenter
3. put it into maintenace mode
4. add to cluster
5. enable ECV
6. exit ESX from maintenance
7. try to make vMotion between old and new node in a cluster
8. if vMotion will not work, as Andre says, you have to power VM down and start it.

Cheers
Artur

Please, don't forget the awarding points for "helpful" and/or "correct" answers.

[kennyhwx]

Hi Artur,

Thanks for your assurance.

Kenny