Install package mdadm
# aptitude install mdadm
Create a new array
# mdadm --create /dev/md0 --level=raid1 --raid-devices=2 /dev/sdb1 /dev/sdc1
Add the new RAID in the main configuration file for mdadm
# mdadm --detail --scan >> /etc/mdadm/mdadm.conf
Now we go to check the status the new array
# mdadm --detail /dev/md0
Next step we go to format new array:
# mkfs.ext4 -v -L "NEWARRAYRAID1" /dev/md0
And we get the UUID with blkid command:
# blkid | grep /dev/md0
We add the next line to file /etc/fstab. And we don’t forget create the folder where you’ll mount the array:
UUID=feeaa6fb-9c7b-4213-8a83-2f9c1ed77a68 /media/RAID1 ext4 defaults 0 1
Finally generate an initramfs image:
update-initramfs -u
We can’t remove a disk directly from the array, unless it is failed, so we first have to fail it:
# mdadm --fail /dev/md0 /dev/sdc1
And now we can remove it:
# mdadm --remove /dev/md0 /dev/sdc1
Verifying the status of the RAID arrays:
# cat /proc/mdstat
or
# mdadm --detail /dev/md0
Add new disc to array:
# mdadm --add /dev/md0 /dev/sdc1
Verifying the status of the RAID arrays:
# cat /proc/mdstat
or
# mdadm --detail /dev/md0
NOTE: if the array is inactive (what happens, for instance, if a disk has dissapeared) before remove and add the new disk the array must be actived with:
# mdadm --run /dev/md0