Performing an Unscheduled Backup of a Domain Controller

Updated: April 29, 2008

Applies To: Windows Server 2008

There are three types of backup that you can perform to back up Active Directory Domain Services (AD DS) on a domain controller. You can also use all three backup types to restore AD DS. A full server backup contains all volumes on the domain controller. To back up only the files that are required to recover AD DS, you can perform either a system state backup or a critical-volumes backup:

  • A system state backup creates a backup that is similar to a backup that you can create by using the Ntbackup tool in Windows Server 2003.

  • A critical-volumes backup includes all files that are stored on all volumes that contain system state files.

A system state backup is not incremental. Therefore, each system state backup requires a similar amount of space. A critical-volumes backup is incremental, which means that it includes only the difference between this backup and the previous backup. However, because the critical-volumes backup can include other files in addition to the volumes that are required for system state, you can expect critical-volume backups to increase over time with unnecessary files.

To help manage the number of versions of system state backups that you store, you can use the wbadmin delete systemstatebackup command. For more information, see Wbadmin delete systemstatebackup (

  • The target volume for a critical-volumes backup can be a local drive or network shared folder, but it cannot be any of the volumes that are included in the backup.

  • If you use an external storage device for the backup, it must be connected to the domain controller that you are backing up.

  • The target volume for a system state backup cannot be a network shared folder.

  • The target volume for a system state backup cannot be the same volume that hosts any of the system state components by default. To change the default, you must add the AllowSSBToAnyVolume registry entry to the server. For more information, see Known Issues for AD DS Backup and Recovery.

  • Do not store critical-volume and system state backups on the same volume.

  • Although Windows Server Backup appears on the Administrative Tools menu by default, you must add Windows Server Backup as a feature in Server Manager before you can use the tool. For more information, see Installing Windows Server Backup.

The procedures in this section provide instructions for performing unscheduled backups of all three backup types. You can use the Windows Server Backup snap-in to perform unscheduled full server and critical-volume backups. For information about performing scheduled backups, see Scheduling Regular Full Server Backups of a Domain Controller. For system state backups, you must use the Wbadmin.exe command-line tool. You cannot use the Windows Server Backup snap-in to back up system state.

To perform backups on a domain controller, use the following procedures:

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