[ceph-users] snapshot-based mirroring explanation in docs

Hi list, When reading the documentation for the new way of mirroring [1], some questions arose, especially with the following sentence: delta will need to be synced prior to use during a failover scenario. 1) I'm not sure I follow. Why are snapshots not point-in-time, whereas using the journal-based mirroring is? 2) Also, I am not sure what the implications are for the second part of the referenced sentence, what significance does the word "full" bear in "full snapshot delta" ? Further, Isn't it obvious that in order to do a failover, the other side should have the latest snapshot? - I am probably missing what the documentation is trying to tell me. All in all, I think some background concepts are missing in order to read this chapter of the documentation. It might well be that this is explained somewhere else in the docs, but maybe we should link to that. If someone can explain the above 2 points, I'm willing to take a shot at making a patch if I can make this clearer in the docs. Thanks, Hans [1] https://docs.ceph.com/docs/octopus/rbd/rbd-mirroring/