mgr: add module which displays current usage of file system (`fs top`)
It would ideally provide a list of sessions doing I/O, what kind of I/O, bandwidth of reads/writes, etc. Also the same information in aggregate form. The other metrics of general interest: caps outstanding, MDS cache size (broken down by type?), cache utilization/hits, client cache utilization (#26996), etc.
#9 Updated by Venky Shankar 3 months ago
for completeness, linking John's performance probes blueprint here, which is really interesting: https://tracker.ceph.com/projects/ceph/wiki/Live_Performance_Probes