Since I'm running Stablebit Drivepool on my server PC it's been trying to unload the drive it picked up as starting to fail, but my other drives were full... so I effectively had no storage left on my server... lame.
Ended up buying a couple of WD Red 10TB drives and a Pcie sata controller and jamming them in this evening. Not really how I'd planned on spending $1,000 at this point in time...but at least I can claim it on tax for uni and work, so there's that.