[ceph-users] Understanding how crush works

Hi list, I have a problem understanding on how crush works when the crush map changes. Let's take a pool with some data in it, and a crush map that enables a client to calculate itself where a particular chunk is stored. Now we add more OSDs, which means, the crush map changes. Now most objects are misplaced, given the new crush map. If the clients wants a particular chunk, it takes the modified map, but as the chunk is misplaced, it won't find it where the crush algorithm points to. How can the client know which crush map to consider when doing the calculation? Do the clients keep several versions of the map, and try them one after the other? Thanks for some hints on this. -- Andre Tann