Upgrading your Ceph cluster software version is relatively simple. You just need to update the Ceph package followed by a service restart and you are done. The upgradation process is sequential and usually does not require any downtime for your storage services if you have configured your cluster in high availability, that is, with multiple OSDs, monitors, MDS, and RADOSGW. As a general practice, you should plan your cluster upgradation during nonpeak hours. The upgradation process upgrades each Ceph daemon one by one. The recommended upgradation sequence for a Ceph cluster is as follows:

You should upgrade all daemons of a specific type and then proceed for upgradation of the next type. For example, if your cluster contains three monitor nodes, 100 OSDS, 2 MDS, and a RADOSGW. You should first upgrade all your monitor nodes one by one, followed by upgrading all OSD nodes one by one, then MDS, and then RADOSGW. This is...