What's scarier: a guy at OSCON got excited about MogileFS, saying he was just starting to design something almost exactly the same. He said he'd just work on MogileFS instead. I asked what he needed it for. I forget the official project name, but it was something like "NASA's Near-Earth Object Detection Center".
So now we joke that MogileFS better not have bugs.
Between his need for checksumming data and the kick-ass presentation of Solaris 10's ZFS with end-to-end checksumming, we've started putting streaming checksumming into it. Don't want to be responsible for an asteroid hitting the Earth or anything.