A while back I was also looking into ways to umount the root partition (raid5 in my case). I was poking around with the kernel to see how real_root_dev etc works, and the way initrd (which I was using) moved the real root device around.. I figured a syscall of some sort could be called at shutdown, to make the final move and umount it. i.e. the initrd ram disk would become the real root again, and the md0 would live off of it. In any case, I remember fairly clearly with mingo's annoucnments, right about when ckraid was eliminated, that the umounting problem was cleanly solved in the kernel itself -- the raid code unmounts it for you automatically! I verified this when I upgraded to the latest code recently, a quick reboot brought the system right back up. So perhaps you guys are just running an older version of the raid patches / code? - lv
