Article ID : 5165
Reviewed : 2018-02-08

Product Version:
AhsayOBM: 7.3.2.0 to 7.x
OS: Windows

ATTENTION 1st January, 2022: v7 officially End-of-Life [details]

What are the restrictions for the temporary storage location of a System State (MS Windows System State Backup module) or System backup (MS Windows System Backup module) image file(s) generated by the Windows WBAdmin.exe utility?

Refer to the following restrictions imposed by Microsoft's Windows Server Backup Feature (WSB), on the storage location for the MS Windows System and System State Backup module.

For System State backup (MS Windows System State Backup module), the target volume CANNOT be a:

• Critical Volume (by default).
  
  Critical volumes refers to the volumes present on the system which house the operating system and other files which are essential for the OS to function properly. In the event of a disaster these volumes are required to bring your server back up and running.
  
  
• Source Volume (by default).
  
  Source volume is any volume that contain a file that is included in the backup (e.g. component selected to be included in the system state data by the WSB during the backup, you do not have the option to exclude any file).
  
  
• Network Share (limitation for Windows Server 2008 only).
  
  Network share refers to a Universal Naming Convention (UNC) path to a remote shared folder.
  
  Important: This restriction only implies to Windows Server 2008. For Windows Server 2008 R2 or above, the target volume can be a network share.

To change the default behavior to allow the target to be a critical or source volume, add the 'AllowSSBToAnyVolume' registry entry to the target server. Refer to the technote for details:

http://support.microsoft.com/kb/944530

Note that, there are known issues with storing a system state backup on a source volume:

• Backup can fail, the backup may be modified during the backup process, which might cause the backup to fail.
  
  
• It causes an inefficient use of target space.
  
  Twice the amount of space is necessary for a backup than for the original data. The volume must allocate twice the amount of space for the shadow copy process.

For System backup (MS Windows System Backup module), the target volume CANNOT be a:

• Critical Volume.
  
  Critical volumes refers to the volumes present on the system which house the operating system and other files which are essential for the OS to function properly. In the event of a disaster these volumes are required to bring your server back up and running.
  
• Source Volume.
  
  Source volume is any volume that is selected for backup (e.g. volume selected in the backup source setting).
  
  Important: Unlike System State backup, no registry change can workaround these restrictions.

For both System and System State backup, the target volume CANNOT be a subdirectory on a local volume.

Windows Server Backup will enforced system and system state data to a 'WindowsImageBackup' folder on the root of the local volume:

{backuptarget}:\WindowsImageBackup


Summary table of all restrictions:

	Critical Volume	Non-critical Volume	USB Volume	Network Share	Subdirectory	Source Volume
System	No	Yes	Yes	Yes	No	No
System State	Yes 1	Yes	Yes	Yes 2	No	Yes 1

¹ Registry modification required: http://support.microsoft.com/kb/944530
² For Windows 2008 Server R2 or above.

Note: For optimal backup performance, it is strongly recommended to use a dedicated local volume for temporary storage of the Windows System Backup and Windows System State image file.

wbadmin, system, systemstate, volume, image