Raid Software (MDx)

Note: If you've problem like ERROR: sector 0. You could use --force option.

Global overview (info)

cat /proc/mdstat

Detailed information

mdadm --misc --detail /dev/mdx

Create a new raid (drives and/or partitions)

mdadm --create /dev/mdx --level=1 --raid-devices=2 /dev/sdaX /dev/sdbX

Add a drive to an existing raid

mdadm /dev/mdx --manage --add /dev/sdbx

Declare an array as failed

mdadm --fail /dev/mdx /dev/sdax

source

Copy partitions (identical partitions)

Especially useful if you've changed a drive (e.g. broken), or if you badly manipulate a disk. Let say it happens on /dev/sda:

# if MBR
sfdisk -d /dev/sdb | sfdisk /dev/sda

# elif GPT (-R for replicate)
sgdisk -R=/dev/sda /dev/sdb

Remove raid partitions

umount -l /dev/mdX
mdadm --stop /dev/mdX
mdadm --zero-superblock /dev/sdaX
mdadm --zero-superblock /dev/sdbX ... etc.

Source

Resync is pending

Might happened if you reboot during a sync, the following command will continue the sync:

mdadm --readwrite /dev/mdx

source