Configure high availability

You enable high availability for a resource pool using the Configure HA wizard. The wizard takes you through the high availability configuration process, step-by-step. During this process, the wizard calculates the server failure limit for the pool given the available resources and the high availability restart priorities you specify.

To open the Configure HA wizard: in XenCenter, select the pool, select the HA tab, and then select Configure HA.


  • On the Pool menu, select High Availability.
  • Right-click in the Resources pane and then select High Availability on the shortcut menu.

To configure high availability on a pool:

  1. Ensure that the high availability requirements are satisfied. For more information, see High availability requirements.
  2. Open the Configure HA wizard.
  3. Click Next on the first page of wizard. The wizard scans the pool for a shared iSCSI, Fibre Channel or NFS LUN to use as the heartbeat SR. If no suitable SR is found, configure some appropriate new storage before you continue.
  4. On the Heartbeat SR page, choose an SR from the list and then click Next.
  5. On the HA Plan page, select one or more VMs in the list and set the required VM startup settings. For more on these options, see VM startup settings.

    Set the following options:

    • HA restart priority: Choose a restart priority for each VM:
      • Choose Restart to ensure the selected VMs are restarted if sufficient resources are available within the pool.
      • Choose Restart if Possible if it is not essential to restart the VM automatically.
      • Choose Do Not Restart if you never want the VM to be restarted automatically.
    • Start order: Specifies the order in which individual VMs start during the recovery operation, allowing certain VMs to be started before others. VMs with a start order value of 0 (zero) start first, then VMs with a start order value of 1, and so on.
    • Attempt to start next VM after: Set a delay interval to wait after starting the VM before attempting to start the next group of VMs in the startup sequence. The next group of VMs are those VMs with a lower start order.
  6. Also on the HA Plan page, under Server failure limit, you can set the number of server failures to allow within this high availability plan. Ensure this value is less than or equal to the maximum failure capacity for the pool, shown here as max. If max is 0 (zero), the pool is overcommitted, and you cannot continue until you resolve the situation. To stop the pool being overcommitted, either adjust the high availability restart priorities or make more resources available within the pool. For more information, see To increase the maximum failure capacity for a pool. Click Next when you have finished high availability plan configuration.
  7. On the last page of the wizard, review your high availability configuration settings. Click Back to go back and change any of the settings or click Finish to enable high availability and close the wizard.
Configure high availability

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