ようやく！ できた！
# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md1 : active raid1 sda1[2] sdb1[1]
970719488 blocks [2/1] [_U]
[>………………..] recovery = 0.2% (1974912/970719488) finish=138.9min speed=116171K/sec
あとはgrub Hard Disk Errorでしょんぼりしないように祈るばかりだ。