The EVC mode of a virtual machine determines the CPU features that a host must have in order for the virtual machine to migrate to that host and power on. The EVC mode of a virtual machine is independent from the EVC mode that you configure for the cluster in which the virtual machine runs.

The EVC mode of a virtual machine is determined when the virtual machine powers on. At power-on, the virtual machine also determines the EVC mode of the cluster in which it runs. If the EVC mode of a running virtual machine or the entire EVC cluster is 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 use any CPU features exposed by the new EVC mode until the virtual machine is powered off and powered on again.

For example, you create an EVC cluster that contains hosts with Intel processors and you set the EVC mode to Intel "Merom" Generation (Xeon Core 2). When you power on a virtual machine in this cluster, it runs in the Intel Merom Generation (Xeon Core 2) EVC mode. If you raise the EVC mode of the cluster to Intel "Penryn" Generation (Xeon 45 nm Core 2), the virtual machine retains the lower Intel "Merom" Generation (Xeon Core 2) EVC mode. To use the feature set of the higher EVC mode, such as SSE4.1, the virtual machine must be powered off and powered on again.

Procedure

  1. Navigate to a cluster or a host in the vCenter Server inventory.
  2. Click the VMs tab.

    A list of all virtual machines in the selected cluster or on the selected host appears.

  3. If the EVC Mode column is not visible, click the angle icon next to any column title and select Show/Hide Columns > EVC Mode.

    The EVC Mode column shows the EVC modes of all virtual machines in the cluster or on the host.

    Important:

    For each virtual machine, the EVC Mode column displays the EVC mode defined at the virtual machine level.

    However, if you do not configure per-VM EVC for a virtual machine, the virtual machine inherits the EVC mode of its parent cluster or host. As a result, for all virtual machines that do not have per-VM EVC configured, the EVC Mode column displays the inherited EVC mode of the parent host or cluster.

    If the virtual machine is in an EVC cluster, the EVC mode that you see in the EVC Mode column is defined in the following manner.

    • When the virtual machine is powered on, the EVC Mode column displays either the per-VM EVC mode, or the cluster-level EVC mode.

      Per-VM EVC

      Cluster-Level EVC

      EVC Mode for the Virtual Machine

      Enabled

      Enabled

      Enabled. The EVC Mode column displays the EVC mode of the virtual machine.

      Disabled

      Enabled

      Enabled. The EVC Mode column displays the EVC mode of the EVC cluster.

    • When the virtual machine is powered off, the EVC Mode column displays the per-VM EVC mode. If per-VM EVC is disabled, the EVC Mode column for the virtual machine is empty.

    When the virtual machine is not in an EVC cluster and per-VM EVC is not configured, the EVC mode that you see in the EVC Mode column is defined in the following manner.

    • When the virtual machine is powered on, the EVC Mode column displays the EVC mode of the parent host.

    • When the virtual machine is powered off, the EVC Mode column is empty.