Ref: E2010 WSB does not support passive database copies (DAG)
http://exchangeserverpro.com/exchange-2010-passive-database-copies-included-backups-dag-members So what do we learn from this? Reminder, the below should be read in conjunction with the notice at the start of the article, as backing up passive database copies using Windows Server Backup is not a supported scenario Yes, passive database copies stored on a volume are backed up by Windows Server Backup Yes, this allows backups of passive database copies to be restored, although not directly Yes, this would allow a backup of a passive database copy to be used for disaster recovery of a database No, the backup time stamp is not written when a passive database copy is backed up, so any monitoring of backups that involves checking that time stamp needs to take that into consideration http://blog.chrislehr.com/2010/03/exchange-2010-dag-backups-using-windows.htm