About Maintenance Mode

Applies To: Virtual Machine Manager 2008 R2, Virtual Machine Manager 2008 R2 SP1

In Virtual Machine Manager (VMM) 2008 R2, you can start maintenance mode for a virtual machine host anytime that you need to perform maintenance tasks on the physical host, such as applying security updates or replacing hardware on the physical host computer.

Note

A host that is in maintenance mode should not be confused with a maintenance host. You start maintenance mode temporarily on a host to perform maintenance tasks to the physical host, while you designate a maintenance host to perform ongoing maintenance tasks to virtual machines. For more information about maintenance hosts, see About Maintenance Hosts.

To start or stop maintenance mode on a host, in the VMM Administrator Console, in Hosts view, click a host, and then in the Actions pane, click either Start maintenance mode or Stop maintenance mode.

Windows-Based Hosts

When you start maintenance mode on a Windows-based host, VMM automatically does the following:

  • On a stand-alone host, places all running virtual machines into a saved state.

  • On a Windows-based host cluster that is capable of live migration, gives you the option to do one of the following:

    • Live migrate all running highly available virtual machines to other hosts in the cluster, and place any running virtual machines that are not highly available in a saved state.

    • Place all running virtual machines into a saved state.

    Warning

    Placing a running virtual machine in a saved state causes a loss of service to any users of that virtual machine.

  • Blocks all virtual machine creation operations on the host.

  • Excludes the host from the host ratings during placement.

    Note

    VMM does not modify the This host is available for placement check box on the Status tab of the Host Properties dialog box.

  • Displays a host status of In Maintenance Mode in Hosts view of the VMM Administrator Console.

When you stop maintenance mode on a Windows-based host, VMM does automatically does the following:

  • Unblocks virtual machine creation operations on the host.

  • Includes the host from the host ratings during placement.

When you stop maintenance mode on a Windows-based host, VMM does not do the following:

  • Automatically restart the virtual machines on a stand-alone host.

  • Automatically move any migrated virtual machines back to the host cluster.

VMware ESX Server Hosts

When you start maintenance mode on an ESX Server host, VMM automatically does the following:

  • Sends an Enter maintenance mode request to the VMware VirtualCenter Server.

    The system behavior of the virtual machines on the selected ESX Server host is determined by the configuration of the VMware VirtualCenter Server.

    Note

    If the VMware Distributed Resources Scheduler is not configured, all virtual machines on the host must be either manually shut down or moved to another host to successfully start maintenance mode on an ESX Server host.

  • Blocks all virtual machine creation operations on the host.

  • Excludes the host from the host ratings during placement.

  • Clears and disables the This host is available for placement check box on the Status tab of the Host Properties dialog box.

  • Displays a host status of In Maintenance Mode in Hosts view of the VMM Administrator Console.

When you stop maintenance mode on an ESX Server host, VMM automatically does the following:

  • Unblocks virtual machine creation operations on the host.

  • Includes the host from the host ratings during placement.

When you stop maintenance mode on an ESX Server host, VMM does not automatically restart the virtual machines on the host.

See Also

Other Resources

Managing Hosts