Creating Backups of Windows 2008 Server Core Machines

Windows 2008 Server Core is a minimalist installation of Windows Server 2008. It must be managed from the servers console command line or remotely via Terminal Services.

In previous versions of Windows Server, NTbackup.exe was the program used for creating system backups. NTbackup.exe has been phased out and has been replaced in Windows 2008 by Windows Server Backup, wbadmin.exe. NTbackup is still available as a separate download in Windows 2008, only for backwards compatibility for restores, so don’t bother trying to use this legacy tool to create backups.

Since the Server Core installation only installs files that are absolutely essential, we’ll first have to install Windows Server Backup. The following command is case sensitive, so type it carefully from the server console:

start /w ocsetup WindowsServerBackup

Now that the Windows Server Backup program is installed, we can start making backups to remote machines.

wbadmin.exe start backup -backuptarget:\\SERVER\SHARE -allCritical -VSSfull -quiet

will create a backup of the entire system and save it to \\SERVER\SHARE, which is a share on a remote machine. Notice that a UNC path is required rather than a mapped drive.

Normally you will be prompted to answer Y/N to “Do you want to start the backup operation?” before the backup begins, but the -quiet command hides this prompt.

To create a System State Backup and save it on the D Drive, use the following syntax:

wbadmin.exe start systemstatebackup -backuptarget:d:

There are a few rules you need to remember about backups in Windows 2008. First, you can’t create a System State Backup on the server’s C Drive. You’ll receive the following message:

ERROR – The location for backup is a critical volume.

I used to be able to create System State backups in Windows 2003 and save them to the C Drive. This was useful for servers that had only one partition, since I’d move the System State backup to a flash drive after it was created. Luckily, KB 944530 describes a registry entry you can create to enable system state backups to critical volumes.

To enable the system state backup files to be targeted to critical volumes, you must set the value of the AllowSSBToAnyVolume registry entry under the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wbengine\SystemStateBackup\

Set the value of this entry as follows:
Name: AllowSSBToAnyVolume
Data type: DWORD
Value data: 1
Note When this value is set to 1, system state backups to any volume are enabled. To revert to the default behavior, set the value to 0.

The next rule, which I find to be particularly ridiculous, is that you cannot save System State backups to a remote share on another server. When I attempted to do this I encountered the following message:

“Creating a system state backup to a shared network folder is not allowed. To store a system state backup on a shared network folder, first run the backup to a local volume and then copy the backup to the shared network folder.”

Sounds great in theory, but like I said before, if you only have a C Drive and no other local volumes, unless you hack the registry the only way you can backup the System State is to do a complete system backup.

The third rule is you can only backup entire volumes, which means no choosing which folders and files are backed up. I find this odd, since I often have folders that I don’t want to ever backup, like temp and cache directories.

Finally, you cannot backup to tape using Windows Server Backup. I’m not really affected by this since I’ve been using disk-to-disk solutions for quite a while now. I can see how this caveat may mess with some admin’s backup strategy, especially those used to keeping long term tape archives.

Comments [5]

  1. Well I am having similar problems. In my case on a 10 disk server system where the boot disk is C: and the 1TB OS images backup disk is z:. Well windows 2008 server is convinced that the Z: is a critical volume! So even with the “fix” when I try to backup the server it tries to backup C: and Z: (in their entirety) to Z:. Obviously that is ridiculous. How does windows server determine that Z: is a critical volume???

  2. strange!! me too having the same problem. but in a differnent manner. Im running an application to start system state backup. The problem is wbadmin tool is telling that my application installation location also a critcal volume. After few hours of headache i found that the registry key of my application causes the problem. If i remove those keys its telling that only C:\ is critical volume. But still i dont find the reason, why my app installation location changed to critical volume. Is there any relationship b/w current working directory entry in registry and wbadmin ??/

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