Ceph

That said, feel free to assign it to me unless someone else is ready to run with it. @zdover23?

We should along the way make it clear that an undeployed drive local to each node is required for this approach. I've long wanted to reserve a drive bay per system for just this sort of thing, but I suspect that capacity pressure means that very few people will have this luxury. One could undeploy an existing OSD and let it recover elsewhere; this sort of defeats the whole idea, but at least it's only one OSD recovering across the net vs. all of them.

Since 12 bay chassis are common and 13 bay chassis aren't, change the example to read 11/12 vs 12/13 to reflect this and be more explicit about the need to reserve or evacuate a drive bay.