The use of Wake-on-LAN (WOL) for the vSphere DPM feature is fully supported, if you configure and successfully test it according to the VMware guidelines. You must perform these steps before enabling vSphere DPM for a cluster for the first time or on any host that is being added to a cluster that is using vSphere DPM.

Before you begin

Launch the vSphere Client and log in to a vCenter Server system.

Before testing WOL, ensure that your cluster meets the prerequisites.

  • Your cluster must contain at least two ESX 3.5 (or ESX 3i version 3.5) or later hosts.

  • Each host's vMotion networking link must be working correctly. The vMotion network should also be a single IP subnet, not multiple subnets separated by routers.

  • The vMotion NIC on each host must support WOL. To check for WOL support, first determine the name of the physical network adapter corresponding to the VMkernel port by selecting the host in the inventory panel of the vSphere Client, selecting the Configuration tab, and clicking Networking. After you have this information, click on Network Adapters and find the entry corresponding to the network adapter. The Wake On LAN Supported column for the relevant adapter should show Yes.

  • To display the WOL-compatibility status for each NIC on a host, select the host in the inventory panel of the vSphere Client, select the Configuration tab, and click Network Adapters. The NIC must show Yes in the Wake On LAN Supported column.

  • The switch port that each WOL-supporting vMotion NIC is plugged into should be set to auto negotiate the link speed, and not set to a fixed speed (for example, 1000 Mb/s). Many NICs support WOL only if they can switch to 100 Mb/s or less when the host is powered off.

After you verify these prerequisites, test each ESXi host that is going to use WOL to support vSphere DPM. When you test these hosts, ensure that the vSphere DPM feature is disabled for the cluster.

Caution:

Ensure that any host being added to a vSphere DPM cluster that uses WOL as a wake protocol is tested and disabled from using power management if it fails the testing. If this is not done, vSphere DPM might power off hosts that it subsequently cannot power back up.

Procedure

  1. Click the Enter Standby Mode command on the host's Summary tab in the vSphere Client.

    This action powers down the host.

  2. Try to bring the host out of standby mode by clicking the Power Oncommand on the host's Summary tab.
  3. Observe whether or not the host successfully powers back on.
  4. For any host that fails to exit standby mode successfully, select the host in the cluster Settings dialog box’s Host Options page and change its Power Management setting to Disabled.

    After you do this, vSphere DPM does not consider that host a candidate for being powered off.