Followed the link to mediasmart but still no clear explanation between duplication of WHS BACKUP and BDBB BACKUP.
WHS BACKUP I know consists of the workstation backups. But what is in the BDBB backups?
The "Enable Duplication" options allows the user to turn Duplication on for the WHS backup databse. If you use BDBB to backup your backup database to a shared folder in Server Storage, you can then choose to enable Duplication for that folder. This should allow your BDBB backup to persist intact in the event of a drive failure.
I hope this helps.
http://www.mediasmartserver.net