You can run your daily/hourly backups on the mirror and not impact performance on your main database.

Right. But the grandparent comment was suggestive of the possibility that he or she wanted the mirror to fulfil multiple roles, including being the backup.

The mirror is to run the backups on, not the backup itself.

CHANGE MASTER TO MASTER_DELAY = 3600;

Your slave will always be 5 minutes behind the master. You were saying?

If this is your tactic, I'd think the binary log would be the winning way to rollback a bad delete.

Well, with a functional mirror to run manual queries against, you wouldn't be running the risk of running such a query on your prod DB anyway. But yeah, you still need a dump.

There's lots of disaster reports that start with "shouldn't" and "normally we wouldn't" :)

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