# re-initialize the raid stack to /dev/md0, 
# creating a /dev/md0 devnode if necessary

umount /raid
mdadm --stop /dev/md0
echo y | mdadm --create /dev/md0 --chunk=512 --raid-disks=4 --level=0 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1

# wait for sync disks, then remount
sync
mkdir /raid
mount /raid

# store settings 
echo 'DEVICE /dev/hd[a-h]1 /dev/sd[a-h]1' > /etc/mdadm/mdadm.conf
mdadm --examine --scan >> /etc/mdadm/mdadm.conf