mdadm-raid10-grow.sh

#!/usr/bin/env bash

for i in {1..8}; do
        truncate -s10m loop-$i
        losetup /dev/loop$i loop-$i
done

mdadm -CR /dev/md0 --metadata 1.1 --level raid10 --raid-disks 4 /dev/loop{1..4}
# recovery
sleep 1m

mdadm /dev/md0 --add /dev/loop{5..8}
mdadm /dev/md0 --grow --raid-devices 8

for i in {1..8}; do
        rm -f loop-$i
        losetup -d /dev/loop$i
done

mdadm -S /dev/md0