I really like this line of thought and I think your instinct is very good here. Remember - if you are in the middle of a potentially failing array, every singl

I really like this line of thought and I think your instinct is very good here. Remember - if you are in the middle of a potentially failing array, every single bit of parity data is pure gold and if you fail out a drive, that drive worth of parity is gone forever. So if you fail out a drive but it was actually weird bus errors getting spammed by some other drive that is actually failing, now you're in trouble ... While on the topic, in filesystem emergencies, don't forget the ability to mount, and even run, read-only. Your filesystem might be puking on mount and backing you into a corner, but perhaps if it were mounted read-only ...