Hi all, we have some Ceph clusters with RGW replication between them. It seems that in the last month at least, it gets stuck at around the same time ~every day. Not 100% the same time, and also not 100% of the days, but in the more recent days seem to happen more, and for longer. With "stuck" I mean that the "oldest incremental change not applied" is getting 5 or more minutes old. In the past this seemed to resolve itself in a short time, but recently it didn't. It remained stuck at the same place for several hours. The output on one end looks like this (I redacted out some of the data because I don't know how much of the naming would be sensitive information): root@zone2:/# radosgw-admin sync status --rgw-realm backup realm xxxxxxxx-xxxx-xxxx-xxxx-8ddf4576ebab (backup) zonegroup xxxxxxxx-xxxx-xxxx-xxxx-58af9051e063 (backup) zone xxxxxxxx-xxxx-xxxx-xxxx-e1223ae425a4 (zone2-backup) current time 2024-08-04T10:22:00Z zonegroup features enabled: resharding disabled: compress-encrypted metadata sync no sync (zone is master) data sync source: xxxxxxxx-xxxx-xxxx-xxxx-e8db1c51b705 (zone1-backup) syncing full sync: 0/128 shards incremental sync: 128/128 shards data is behind on 3 shards behind shards: [30,90,95] oldest incremental change not applied: 2024-08-04T10:05:54.015403+0000 [30] while on the other side it looks ok (not more than half a minute behind): root@zone1:/# radosgw-admin sync status --rgw-realm backup realm xxxxxxxx-xxxx-xxxx-xxxx-8ddf4576ebab (backup) zonegroup xxxxxxxx-xxxx-xxxx-xxxx-58af9051e063 (backup) zone xxxxxxxx-xxxx-xxxx-xxxx-e8db1c51b705 (zone1-backup) current time 2024-08-04T10:23:05Z zonegroup features enabled: resharding disabled: compress-encrypted metadata sync syncing full sync: 0/64 shards incremental sync: 64/64 shards metadata is caught up with master data sync source: xxxxxxxx-xxxx-xxxx-xxxx-e1223ae425a4 (zone2-backup) syncing full sync: 0/128 shards incremental sync: 128/128 shards data is behind on 4 shards behind shards: [89,92,95,98] oldest incremental change not applied: 2024-08-04T10:22:53.175975+0000 [95] With some experimenting, we found that redeploying the RGWs on this side resolves the situation: "ceph orch redeploy rgw.zone1-backup". The shards go into "Recovering" state and after a short time it is "caught up with source" as well. Redeploying stuff seems like a much too big hammer to get things going again. Surely there must be something more reasonable? Also, any ideas about how we can find out what is causing this? It may be that some customer has some job running every 24 hours, but that shouldn't cause the replication to get stuck. Thanks in advance, -- Olaf Seibert Site Reliability Engineer SysEleven GmbH Boxhagener Straße 80 10245 Berlin T +49 30 233 2012 0 F +49 30 616 7555 0 https://www.syseleven.de https://www.linkedin.com/company/syseleven-gmbh/ Current system status always at: https://www.syseleven-status.net/ Company headquarters: Berlin Registered court: AG Berlin Charlottenburg, HRB 108571 Berlin Managing directors: Andreas Hermann, Jens Ihlenfeld, Norbert Müller, Jens Plogsties