How to Delete Non-System State Backups in Windows 2008R2

Question

Hello,
I am running a Windows 2008R2 server which uses Windows Server Backup to do the backups. We are using the backup-tool to create non-system state backups of the data-directories on this machine. The backup is done on a dedicated disk connected through iscsi
(to a Synology box). This backup disk has become too small and we have now replaced the Synology box with a bigger one. Here i created a new LUN again for the backup purposes.
Now for my question; The wbadmin.exe tool supplied with W2008R2 does not offer a way to delete the old backups. I know that in Win2012 (which we we also have running) I could add the new iscsi location and then (when enough backups are available on the new
target) use wbadmin.exe delete backup  to delete the old non-system state backups; e.g.
 wbadmin delete backup -version:08/07/2013-21:00
This (very undocumented) feature of Windows 2012 and higher works quite nice and is exactly what i am searching for on the W2008R2 machine; a way to delete the old backups (and under the hood delete the corresponding snapshots)
I've done quite a bit of research and it should be possible to do something similar in 2008 but then manually, The howto is described in the following link: http://blogs.technet.com/b/filecab/archive/2009/06/22/backup-version-and-space-management-in-windows-server-backup.aspx .
Basically it describes that you should use DiskShadow.exe to remove e.g. the oldest snapshot with a  command like :
Delete shadows OLDEST \\?\Volume{7fc1871b-2e1f-11dd-a339-001e4fb7af35}
Windows Server backup (wbadmin) should then on the next run 'see' this deletion and update its list of available backups:
"You can perform the same steps manually to delete backups on demand. However, the backup catalog update cannot be done manually and it will happen instead during
the next backup."
I've done this on our box and it indeed removes the shadows from the list. However, in the Windows Backup 'dashboard' it still lists the backups as available. Also after a new backup has finished (according the the article this is when it should 'update'
its backup catalog). When I try to restore a backup from a date that i just removed it gives a nice message that this is impossible because the snapshot is not available (duh :)) ;
Unable to browse Local disk. The shadow copy of the backup stored on the backup destination cannot be found.
So it seems that the aforementioned method works; it removes the snapshot and frees diskspace, but it doesn't update the Windows Backup catalog. As a result the management tool (GUI) still lists the backups which are no longer available! How can i change
this? Is there any way to do this? I found one article which mentions that the Dashboard bases its screen on the Windows Logs and not on the actual VSS snapshots available:
http://forum.wegotserved.com/index.php/topic/23757-start-afresh-with-server-backup/ (WHS) In my situation however this seems unlikely because i don't have any logs that date back as far as my backups go.
In my opinion this is a real bug and it leaves us with a in-consequent backup schema. Does anyone have similar situations or even a solution to my problem?
Kind Regard, Martin

Answer 1

Hi Mandy,
Yes! I think i got my answer and I now get how windows backup works in Windows 2008 :-) It turns out that I dismissed some suggestions a bit too soon. The answer lies in the command mentioned earlier : 
Wbadmin delete catalog
This command does delete all the backups from a perspective of the Windows Backup UI, but leaves the VSS snapshots intact. This means that the backups are still available, but you just can't restore them with the User Interface. In order to 'update' the
UI with the current available snapshots (which you can list with diskshadows list shadows all), you have to re-add the existing media on which the backups took place using the Wizard of the UI. It will then inform you that existing backups are available and
if you want to keep these for restore purposes. If you click 'yes', and THEN perform a backup ... All the current available backups will be shown in the User Interface :-) 
So for my steps taken to change from one iscsi (iscsi1) to another (iscsi2):
- Add the 2nd iscsi target with the Windows Backup UI
using Backup schedule , Modify backup -> [desired options] => Add more backup destinations -> iscsi2
- Remove the 1st iscsi target with the Windows Backup UI
using Backup schedule , Modify backup -> [desired options] => Remove current backup destinations -> iscsi1
- Run some backups on the new destination. Old restore points are now still available. When enough restore points are available on the new volume iscsi2 start deleting old data from iscsi1 as follows:
- Run diskshadow
diskshadow
- list all the current snapshots
list shadows all
- remove all the snapshots of iscsi1  (repeat until all shadows are gone of iscsi1)
delete shadows oldest \\?\volume{yourvolumeid}\
- delete the windows backup catalog
wbadmin delete catalog
- Restart the windows backup UI and re-add your schedule on the new volume iscsi2. It will now ask if you want the keep the existing data for restore purposes; click yes. 
- After the next backup only the backups of volume iscsi2 will be listed and everything is fine ! 
I Hope my post will help others with similar questions. It was quite a search before I understood the way it works. Basically as long as your VSS snapshots are still available and listed by diskshadow you still have the backups and you will be able to get
this in sync with the steps above (delete schedule and re-add originating targets containing the snapshots). After the next backup the UI will update itself. 
(In my case someway along the way I lost my originating snapshots, but because I already had my new backup set it didn't bother me; It kept me from having to delete all 510 old backups :) with diskshadow)
Regard, Martin