Comment 3 for bug 1276787

I like option 2 in comment 2 best so far (no strong feelings at the moment on a vs b). My concern with simply failing if the backend doesn't support the snapshot's original type is that from a user persecutive, I have no easy way to know which snapshots are valid. Horizon simply offers up all available snapshots without any filtering based on backend appropriateness. It also seems onerous on the user to force them into a 2 step process of create the snapshot with the original settings and then migrate and change type when that is something that *could* be automated. I understand it would require a lot of work from a programmers perspective, but we must also consider the user perspective.