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.
For example, consider a cluster containing hosts with Intel Xeon 45nm Core™ 2 processors that have been set to the Intel® "Merom" Generation (Xeon® Core™ 2) EVC mode. A virtual machine powered on in this cluster runs in the Intel "Merom" Generation (Xeon Core 2) EVC mode. If the cluster's EVC mode is raised to Intel "Penryn" Generation (Xeon 45nm Core 2), the virtual machine remains at the lower Intel "Merom" Generation (Xeon Core 2) EVC mode. To use any of the features exposed by the higher cluster EVC mode, such as SSE4.1, you must power off the virtual machine and power it on again.
You can use the Virtual Machines tab of a cluster or a host to determine the EVC modes of the running virtual machines.
- You must be connected to a vCenter Server system with the vSphere Client.
- Select the cluster or host in the inventory.
- Click the Virtual Machines tab.
- If the EVC Mode column is not displayed, right-click on the column titles and select EVC Mode.
The EVC modes of all running or suspended virtual machines are displayed in the EVC Mode column. Powered off virtual machines and virtual machines that are not in EVC clusters show N/A as the EVC mode.