In my previous post, I reported that a user wanted to backup the Mirror Database.  This is not possible.  Backups of any kind on the mirror db is not a valid operation.

This same person presented an idea that I had heard of before, but wanted to double-check before blogging about it.  The scenario is basically this - he wants to BREAK the mirror (stop the mirroring session - drop the partnership) and then backup up the mirror db.  Well, you can stop the session, drop the partnership, and recover on the server formerly known as the mirror, and back it up.  The “not so nice” aspect of this scenario is if he wants the mirroring to be re-established, a full backup from the principal must then be restored on the Mirror and a partnership setup again. 

So, yes you can BREAK the mirror in order to perform a backup on the server formerly known as the mirror.  There may be a good reason to do so.  But it doesn't relieve you of your responsibility of doing a full backup on the Principal - especially if you want to re-establish mirroring.  Mirroring is still one of the collest features coming in SQL Server 2005.