The sfdisk is because as part of our kickstart file we only create the first partition. After removing the disk from the raid we repartition it.

I don't see why this couldn't fix up a RAID device generated by the debian installer. The device name could be parameterized if it's not always the same.

We run this script before there's any real data on the device so loss of redundancy for a brief moment is not a huge deal - md0 is a very small device so it doesn't take long to resync.