I remember a few months back when someone hit the emergency power switch to
the whole floor where we host at Internap. Subsequently the backup power
system had a cascading failure. Livejournal, who also hosts there, was up
all night and into the next day restoring their mysql databases after a
bunch of them were corrupted. I believe they had write cache turned on.
Of course our postgresql servers on scsi drives came right back up. If it
wasn't for a couple of servers that won't reboot automatically if the power
goes out I wouldn't have even had to go down to the data center.
Chris