Vlad is now alive again.
After spending a significant chunk of Saturday grubbing around on the floor, elbow-deep in computers (think James Herriot, only less gooey and with sharper edges), I've diagnosed vlad's problems: At least one of the two hard drives in the RAID-1 array containing my home directory has media errors, and the motherboard has decided to stop working entirely.
At about half eleven last night, my server, vlad, died. Quite comprehensively.