boot into the system using a live cd like knoppix or kubuntu live.
chose your input method, i prefer the german keyboard.
# dpkg-reconfigure keyboard-settings
since livecds normally do not ship with mdadm, install mdadm into the live cd (remember to repeat that everytime you’ve booted).
# apt-get install mdadm
get an idea about your disk layout.
# ls -la /dev/sd*
assemble the drives on RAID1 level, mounting them.
# mkdir /mnt/md0 /mnt/md1 /mnt/md2 /mnt/md4
# mdadm -A /dev/md0 /dev/sda1 /dev/sdb1 # mdadm -A /dev/md1 /dev/sda2 /dev/sdb2 # mdadm -A /dev/md2 /dev/sda3 /dev/sdb3 # mdadm -A /dev/md3 /dev/sda4 /dev/sdb4
if you get one “cannot open device …: Device or resource busy. … has no superblock – assembly aborted”, this will be most likely the swap partitions you’ve set (which I do not add to RAID1 level normally).
now, mount all the assembled raid arrays.
# mount /dev/md0 /mnt/md0 # mount /dev/md1 /mnt/md1 # mount /dev/md2 /mnt/md2 # mount /dev/md3 /mnt/md3
check the mounts with
# mount
and then go to the mounted partitions
# cd /mnt/
and copy your data to your preferred backup media (usb disk, etc).