Ceph

Hi.

After reading the documentation it is not clear for me, how downgrade processes should be performed over the solution. Could you please describe somewhere in the documentation:

- How to downgrade Ceph to the older version (hopefully with no downtime)
- Maybe some compatibility policies and notes between versions

Such information is really important foor the users, if something goes wrong with the newer Ceph version (and the upgrade is fully performed). If you do not support downgrade in any way - please mention it explicitly and provide some alternative scenario (like set up new Ceph cluster with an old version and import data from a backup).

Thanks in advance!