Basic Commands Checking status of drive/arrays, displaying all raids and basic information # cat /proc/mdstat  Detailed status of array # mdadm --detail /dev/md2 Creating raid device # mdadm --create --verbose /dev/mdX --level=RAID5--raid-devices=2 /dev/sdj /dev/sdk  Stoping raid device # mdadm --stop /dev/md2  Adding a drive: # mdadm /dev/md2 -a /dev/sdm  Marking a drive as failed (This will break things if your not careful) # mdadm --manage --set-faulty Read more...