If You have array with 9 devices and add another one You may at same time grow array and change raid level. In this case You not need backup file. Please try this: mdadm --grow /dev/md0 --raid-devices=10 --level=6 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html