What are you expecting fdisk to tell you? fdisk lists partitions and I suspect you didn't have any partitions on /dev/md0 More likely you want something like fsck -n -f /dev/md0 and see which one produces the least noise.
Maybe a simple file -s /dev/md0 could do the trick, and would only produce output different from the mere "data" when the good configuration is found... -- F.-E.B. - 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