Uuuugh
Had to wait days to get the server back online because the replacement hard drive appears to have been DOA so I had to get a replacement replacement hard drive, but the original drive failed entirely before that got here...
So... finally back up and running.
(I do have a Raid-5 style setup under LVM, so thankfully that means no data was lost... but it wasn't in a great position to run it in the mean time. I plan to try and upgrade it to RAID-6 style soonish so I can safely run it deprecated... as well as a few other configuration changes that'll help performance and reliability)