Some cephfs tool commands silently operate on only rank 0, even if multiple ranks exist
I think this is biting people, e.g. in thread "[ceph-users] CephFS - How to handle "loaded dup inode" errors"
We made commands like cephfs-journal-tool operate on rank 0 by default, at a time when single MDS systems were the norm.
On a system with many MDS ranks, it is confusing to run this command, see it succeed, but have it only act on one rank. Maybe we should change the default to all ranks, or maybe we should warn the user that they're only acting on one, but the current silent behaviour is a bit awkward.
We could get rid of the default option entirely, as it is also kind of scary that these commands will operate (I think?) on the default filesystem when there are multiple filesystems, which makes it easy for someone to forget they have multiple filesystems, and do a "reset" on a particular rank forgetting which one they're acting on.