6.0

Table Of Contents
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.
Prerequisites
n
You must be connected to a vCenter Server system with the vSphere Client.
n
If you intend to lower the EVC mode, power off any currently running virtual machines with a higher
EVC mode than the one you intend to enable. See “Determine EVC Modes for Virtual Machines,” on
page 130.
Procedure
1 Display the cluster in the inventory.
2 Right-click the cluster and select Edit Settings.
3 In the left panel, select VMware EVC.
The dialog box displays the current EVC settings.
4 To edit the EVC settings, click Change EVC Mode.
5 From the VMware EVC Mode drop-down menu, select the baseline CPU feature set you want to enable
for the cluster.
If the selected EVC Mode cannot be selected, the Compatibility pane displays the reason or reasons
why, along with the relevant hosts for each reason.
6 Click OK to close the EVC Mode dialog box, and click OK to close the cluster settings dialog box.
Determine EVC Modes for Virtual Machines
The EVC mode of a virtual machine defines the CPU features that the virtual machine can access. The
virtual machine's EVC mode is determined when it is powered on in an EVC-enabled cluster.
When a virtual machine is powered on, it determines the EVC mode of the cluster in which it is running. If
the EVC mode of the cluster is subsequently raised, the virtual machine does not change its EVC mode until
it is powered off and powered on again. This means that the virtual machine does not make use of any
additional CPU features exposed by the cluster's new EVC mode until the virtual machine has been
powered off and powered on again.
vSphere Administration with the vSphere Client
130 VMware, Inc.