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 activating 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.

Prerequisites

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

  • Your cluster must contain at least two hosts that are version ESX 3.5 (or ESX 3i version 3.5) or later.
  • 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 deactivated 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 deactivated 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. Browse to the host in the vSphere Client.
  2. Right-click the host and select Power > Enter Standby Mode
    This action powers down the host.
  3. Right-click the host and select Power > Power On to attempt to bring it out of standby mode.
  4. Observe whether or not the host successfully powers back on.
  5. For any host that fails to exit standby mode successfully, perform the following steps.
    1. Select the host in the vSphere Client and select the Configure tab.
    2. Under Hardware > Power Management, click Edit to adjust the power management policy.
    After you do this, vSphere DPM does not consider that host a candidate for being powered off.