Configure EVC to ensure that virtual machine migrations between hosts in the cluster do not fail because of CPU feature incompatibilities.
Several EVC approaches are available to ensure CPU compatibility:
- If all the hosts in a cluster are compatible with a newer EVC CPU or Graphics (vSGA) mode, you can change the EVC CPU or Graphics (vSGA) mode of an existing EVC cluster.
- You can enable EVC for a cluster that does not have EVC enabled.
- You can raise the EVC mode to expose more CPU features.
- You can lower the EVC mode to hide CPU features and increase compatibility.
- Verify that all hosts in the cluster have supported CPUs for the EVC mode you want to enable. See Knowledge Base article KB 1003212 for a list of supported CPUs.
- Verify that all hosts in the cluster are connected and registered on vCenter Server. The cluster cannot contain a disconnected host.
- Virtual machines must be in the following power states, depending on whether you raise or lower the EVC mode.
EVC Mode Virtual Machine Power Action Raise the EVC mode to a CPU baseline with more features. Running virtual machines can remain powered on. New EVC mode features are not available to the virtual machines until they are powered off and powered back on again. A full power cycling is required. Rebooting the guest operating system or suspending and resuming the virtual machine is not sufficient.Tip: You can configure a virtual machine to power cycle when its guest OS is rebooted, by setting the vmx.reboot.powerCycle VM parameter to TRUE. When the virtual machine is powered back on, this configuration parameter is removed. To edit the virtual machine configuration settings, you can use the VMware Host Client. See Edit the Configuration File Parameters in the VMware Host Client topic in the vSphere Single Host Management - VMware Host Client guide. See the VMware vSphere Blog post for information about how to set this parameter to a group of virtual machines using VMware PowerCLI. Lower the EVC mode to a CPU baseline with fewer features. Power off virtual machines if they are powered on and running at a higher EVC mode than the one you intend to enable.Note: When you take a snapshot of a virtual machine in an EVC cluster, keep in mind the following use cases:
- If you take a snapshot of a running virtual machine before an EVC downgrade, an attempt to revert to that snapshot after the EVC downgrade will fail and the virtual machine will be left in a suspended state.
- If you take a snapshot of a virtual machine before an EVC upgrade, you can revert to the snapshot taken before the EVC upgrade.
To verify the EVC mode for virtual machines, see Determine the EVC Mode of a Virtual Machine.
- Select a cluster in the inventory.
- Click the Configure tab.
- Under Configuration, select VMware EVC, and click Edit.
- On the Change EVC Mode page, select whether to enable or disable EVC.
Option Description Disable EVC The EVC feature is disabled. CPU compatibility is not enforced for the hosts in this cluster. Enable EVC for AMD Hosts The EVC feature is enabled for AMD hosts. Enable EVC for Intel Hosts The EVC feature is enabled for Intel hosts.
- From the CPU Mode drop-down menu, select the baseline CPU feature set that you want to enable for the cluster.
If you cannot select the EVC CPU Mode, the Compatibility pane displays the reason, and the relevant hosts for each reason.
- (Optional) From the Graphics Mode (vSGA) drop-down menu, select a baseline graphics feature set.
If you cannot select the EVC vSGA Mode, the Compatibility pane displays the reason, and the relevant hosts for each reason.
Option Description Baseline Graphics Applies the Baseline Graphics feature set that includes features through Direct3D 10.1/OpenGL 3.3.Note: Graphics Mode (vSGA) applies only the Baseline Graphics set that includes features through Direct3D 10.1/OpenGL 3.3. The Baseline Graphics feature set is compatible with all supported features for ESXi 7.0 or earlier. D3D 11.0 class features Applies the baseline graphics feature set that includes features through Direct3D 11.0/OpenGL 4.1.Note: When you create a cluster, if you enable EVC graphics mode D3D 11.0 class features, you can add only ESXi hosts that support Direct3D 11.0 to the cluster. When you try to add an ESXi host that does not support Direct3D 11.0 to the cluster, the operation fails with an error message.
- Click OK.