Reminder : Mdadm commands
I'll try to sum up here everyday needed commands with mdadm. Of course, you'll need to replace partitions letters and numbers by yours. Every line is a different command and require root privileges. Install raid manager (mdadm) on Debian based distros (Ubuntu, Linux Mint...) apt-get install mdadm Create a new raid with all disks presents mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1 Create a new raid with only one present (use it to migrate a single drive to a raid : first create the raid with one disk, copy data, complete the raid with the second disk) mdadm --create /dev/md0 --level=1 --raid-devices=2 missing /dev/sda1 Get a quick overview of raids running on the system cat /proc/mdstat Get full details of a raid mdadm --detail /dev/md0 Assemble an existing raid with all disks presents mknod /dev/md0 b 9 0 mdadm --assemble /dev/md0 /dev/sda1 /dev/sdb1 Assemble a 2-disks raid with only one present