Created attachment 1934117 [details]
Dashboard snapshot

Description of problem:
We display a column in images tables of mirroring page in our dashboard named "Entries behind primary". This is specific to journal based mirroring.

Either display Not Applicable or Display snapshot based mirroring specific information.

Version-Release number of selected component (if applicable):
16.2.10-84.el8cp


Steps to Reproduce:
1. Configure snapshot based mirroring inbetween two clusters with some images and check mirroring page in dashboard

Actual results:
(Mentioned above)

Expected results:
Accurate/apt information

Additional info:
information specific to rbd-mirroring
[root@e22-h20-b02-fc640 ~]# rbd mirror image status test_mirror/set_2_image_9 --debug-rbd 0
set_2_image_9:
  global_id:   ce59f3b9-986c-4641-9869-f69c6516e798
  state:       up+stopped
  description: local image is primary
  service:     e22-h24-b01-fc640.xrklhe on xxx.xxxx.xxx.com
  last_update: 2022-12-22 14:39:13
  peer_sites:
    name: site-a
    state: up+replaying
    description: replaying, {"bytes_per_second":0.0,"bytes_per_snapshot":0.0,"local_snapshot_timestamp":1671719511,"remote_snapshot_timestamp":1671719511,"replay_state":"idle"}
    last_update: 2022-12-22 14:39:02
  snapshots:
    1924390 .mirror.primary.ce59f3b9-986c-4641-9869-f69c6516e798.1940dbe6-cf35-43bb-bb24-935e2472a013 (peer_uuids:[cf28d399-a04f-49ac-a62b-5de6ff3e21eb])



Ref - https://github.com/ceph/ceph/blob/main/src/pybind/mgr/dashboard/controllers/rbd_mirroring.py#L234-L238