Specifications

4 Move the host into the cluster.
You can power on the virtual machines on the host, or migrate virtual machines into the cluster with
vMotion, if the virtual machines meet CPU compatibility requirements for the cluster’s EVC mode. Virtual
machines running on hosts with more features than the EVC mode must be powered off before migration
into the cluster.
5 Repeat Step 3 and Step 4 for each additional host that you want to move into the cluster.
Enable EVC on an Existing Cluster
Enable EVC on an existing cluster to help ensure vMotion compatibility between the hosts in the cluster.
Prerequisites
Before you enable EVC on an existing cluster, ensure that the hosts in the cluster meet the requirements listed
in “EVC Requirements,” on page 119.
Procedure
1 Select the cluster for which you want to enable EVC.
2 If virtual machines are running on hosts that have feature sets greater than the EVC mode you intend to
enable, ensure that the cluster has no powered-on virtual machines.
n
Power off all the virtual machines on the hosts with feature sets greater than the EVC mode
n
Migrate the cluster’s virtual machines to another host using vMotion.
Because these virtual machines are running with more features than the EVC mode you intend to set,
power off the virtual machines to migrate them back into the cluster after enabling EVC.
3 Ensure that the cluster contains hosts with CPUs from only one vendor, either Intel or AMD.
4 Edit the cluster settings and enable EVC.
Select the CPU vendor and feature set appropriate for the hosts in the cluster.
5 If you powered off or migrated virtual machines out of the cluster, power on the virtual machines in the
cluster, or migrate virtual machines into the cluster.
Any virtual machines running with a larger feature set than the EVC mode you enabled for the cluster
must be powered off before they can be moved back into the cluster.
Change the EVC Mode for a Cluster
If all the hosts in a cluster are compatible with the new mode, you can change the EVC mode of an existing
EVC cluster. You can raise the EVC mode to expose more CPU features, or lower the EVC mode to hide CPU
features and increase compatibility.
To raise the EVC mode from a CPU baseline with fewer features to one with more features, you do not need
to turn off any running virtual machines in the cluster. Virtual machines that are running do not have access
to the new features available in the new EVC mode until they are powered off and powered back on. A full
power cycling is required. Rebooting the guest operating system or suspending and resuming the virtual
machine is not sufficient.
To lower the EVC mode from a CPU baseline with more features to one with fewer features, you must first
power off any virtual machines in the cluster that are running at a higher EVC mode than the one you intend
to enable, and power them back on after the new mode has been enabled.
Chapter 12 Migrating Virtual Machines
VMware, Inc. 121