We have a couple of Windows Server 2012 machines we need to back up. I have set up an Openfiler box to store all the backups on. I've created a couple iSCSI LUN's and attached them to the machines to back up to. For the Exchange server, it works perfectly fine, but for one of the DC's it fails. They are both configured the exact same way.
In the application log, I see:
The backup operation that started at '2013-05-08T14:10:16.128584700Z' has failed with following error code '0x807800C5' (There was a failure in preparing the backup image of one of the volumes in the backup set.). Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.
In the Backup_Error log, it just says "Backup of volume C: has failed. The specified backup disk cannot be found."
The disk is there just fine, it even creates the whole "WindowsImageBackup" folder structure.