convert /dev/md0 to /dev/sda1 - raid 1:
here's metadata at the start of the partition:
mdadm -E /dev/sda1
File system starts at (Data Offset). Use 'fdisk -u /dev/sda', and check partition table with 'p'. Note the start/end, delete it, and recreate it with the first sector being the old number plus the (Data Offset).