Erica told me the drive upstairs was loud enough that she thought it was the laptop in front of her.
I didn't REALLY register this, since I'd been hearing a faint whine off and on for months.
I logged into the server and no errors in syslog.
I get home and it is very loud from the entryway.
The console shows /dev/sda1 I/O error. Blah.
In a panic I shut it off.
Long story short, it turned out that the noisy drive was /storage/movies, a 73g Quantum Atlas 10k. An empty space, then another bay below it containing / and /home.
I don't know if it was luck, or heat from the band-saw noise, or what, but we lost both drives, 100g of scsi, together.
/storage/movies is no biggie. I've bought most of ZIM already, and the stuff in there was backups of things we have on hard media.
/home sucked. 8 days of whatever has changed.