mdadm.md

mdadm - linux software raid

Create software raid5 with mdadm

1. prepare disk. (skip)

2. create newe raid5 with mdadm

# mdadm -C /dev/md0 -a yes -l5 -n3 -x0 /dev/sdb /dev/sdc /dev/sdd

3. check state

# mdadm -D /dev/md0

4. make filesystem and mount

# mkfs.ext4 /dev/md0
# mount /dev/md0 /mnt

5. setup raid in configure files

# mdadm -Ds /dev/md0 >> /etc/mdadm.conf
# blkid
# vim /etc/fstab
+ /dev/md0 /mnt ext4 defaults 0 0
OR
+ UUID=xx /mnt ext4 defaults 0 0
# cat /proc/mdstat
# mdadm -D /dev/md0

6. simulate disk failure

# mdadm /dev/md0 --fail /dev/sdd
# mdadm -D /dev/md0
# mdadm /dev/md0 --remove /dev/sdd
# mdadm --zero-superblock --force /dev/sdd
# mdadm /dev/md0 --add /dev/sdd

7. stop an md

# mdadm -S /dev/md0  ## and then edit fstab, mdadm.conf

8. assemble md

# mdadm -A /dev/md0 /dev/sdx /dev/sdy /dev/sdz

Ref

https://wiki.gentoo.org/wiki/Filesystem/Security
https://wiki.archlinux.org/index.php/RAID