MDADM

Start manual mdadm RAID-Check

With the below command you can start a manual raid-check, just change md0 to your raid name.

echo check > /sys/block/md0/md/sync_action

With the below command you can stop a running raid-check, just change md0 to your raid name.

echo idle > /sys/block/md0/md/sync_action

Add new disk

mdadm --manage /dev/md0 --add /dev/sdx1

Remove disk

mdadm --manage /dev/md0 --set-faulty /dev/sdx1
mdadm --manage /dev/md0 --remove /dev/sdx1

mdadm --assemble --run --force /dev/md3 /dev/sd[a-x]1