The /proc/mdstat file is a dynamically modified log file, which provides the current status of all the RAID devices on the system. We can confirm that the initialization is complete by displaying the file, with the following command:

cat /proc/mdstat

This may take some time to complete, depending on the size of the attached drives.

The preceding screenshot shows the result of this command. You will notice that our array is called md0 and that it consists of two physical drives, called sda and sdb.

It's now time to format the drives in our RAID array. We will use the mkfs.ext4 command to do this, as shown in the screenshot that follows the command line:

mkfs.ext4 /dev/md0

The new Mdadm installer creates an mdadm.conf file in the /etc/mdadm directory.

All the partitions...