Nicolas CANIART napisał(a):
As far as I can tell the disk actually used is /dev/sdb1 (sda1 content is outdated).
check /proc/mdstat to be sure.
I tried to force the array assembly but I got : % mdadm -A /dev/md0 --force md: md0 stopped. mdadm: /dev/sda1 has no super block - assembly aborted So I tried to make sda1 faulty, remove it then reinstall it; but I got : % mdadm --fail /dev/md0 /dev/sda1 mdadm: cannot get array info for /dev/md0 As far as I understand, it's because md0 is active... but I can't activate it; It's a dead lock !!
You need to hot-add a drive to mirror set. If you are really sure it's /dev/sda1 which is unused, just mdadm --manage /dev/md0 --add /dev/sda1
HTH