I now have a new disk. I'm trying to copy the data off of the RAID so I can reformat it but it keeps oopsing. But weirdly after I power cycle (won't respond even to ctl-alt-del) I can successfully copy the same file. I can tell it's picking up where it left off because rsync starts with a few files back from where it locked up (I assume it's a few files back because of some delayed commit? all of these are on reiserfs).
This is pretty lame. I'm now to the "L" in my music but that's only maybe two thirds of the data. (...there, it died on "M".)