Re: Drive mirroring.
@Alister
I've done the whole replaced the failed drive in a mirror set and copy the new drive to the old while out on a warranty repair case.
I hadn't done a backup first (not part of the warranty service), but I had asked the client if he had a backup before I headed to site. And again when I got there. And again after shutting down the non-hotswap "server" before pulling out the failed drive. And again when I inserted the new drive. And finally before putting power to the system.
When the mirror completed rebuilding there was no boot device.
Reboot, check BIOS boot order is correct.
Boot with a live Linux CD, both HDD completely blank. Crap.
Ask client for install dvd and backups.
They don't have either one, they had never done a backup.
I hope they learned their lesson and took backups from then on.