Show device details
mdadm --detail /dev/md127Verify device statuses
cat /proc/mdstatmdadm --create --verbose /dev/md0 --level=6 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sddAdd the device
mdadm --add /dev/md2 /dev/sde1Grow the RAID
mdadm --grow --raid-devices=5 /dev/md2