Failed mdadm software raid 1. No problem, just replace the drive, right?
Raid rebuilds..... Waiting game....
Finish rebuild. Runs for a bit. All of a sudden, the original drive looses its mind and all of the filesystem superblocks (along with the backups).
What to do now eh?
Here is what I did:
Boot the venerable old SysrescueCD mdadm --stop /dev/mdXX (for the misbehaving raid) mdadm --assemble --force /dev/mdXX /dev/sdXX <-where the fresh drive is sdXX (note - leave that turd original drive out - the one without the superblocks).
Now we can mount and check the mdXX raid and verify we can start again.
Wheeeeeee. Such is life sometimes.