Snaptrim is the process of removing a snapshot and reclaiming diskspace after it got deleted. I don't know how the ceph internals work, but it helped for us.
You can try to move the snaptrim into specific timeframes and limit it to one per osd. Also sleeping (3s worked for us) between the deletion helped to alleviate the pressure from the OSDs. Please check the documentation for the exact config parameters. I don't know if octopus got the tooling to remove the pg log dups. Check "ceph-objectstore-tool --help" if the --op parameter accepts trim-pg-log-dups croit made a blog post how to remove these dups: https://croit.io/blog/oom-killer-osds But be warned: Checking an 8TB Samsung SAS SSD with 300pgs (not trimming) took 4 hours. You can skip the listing and counting and just start the trim directly. But the OSD needs to be offline for it. What we did when we were hit with this issue: Stop snaptrim, update to pacific, do an offline rocksdb compression before the OSDs start after the upgrade, start the OSDs and hate our lives while they started, wait a week, slowly start the snaptrim and hope for the best. :-) Mit freundlichen Grüßen - Boris Behrens > Am 06.12.2023 um 20:17 schrieb Peter <peter...@raksmart.com>: > > > Thank you for pointing this out. I did check my cluster by using the article > given command, it over 17 million PG dups over each OSDs. > May I know if the snaptrim activity takes place every six hours? If I > disable the snaptrim, will it stop the slow ops temporarily before my > performing version upgrade? > If I want to upgrade my Ceph, it will take time to analysis the environment. > Can I have work around quickly for delete OSD then create it again for > zeroized the log times? or manually delete the OSD log? > > > > From: Boris <b...@kervyn.de> > Sent: Wednesday, December 6, 2023 10:13 > To: Peter <peter...@raksmart.com> > Cc: ceph-users@ceph.io <ceph-users@ceph.io> > Subject: Re: [ceph-users] Assistance Needed with Ceph Cluster Slow Ops Issue > > Hi Peter, > > try to set the cluster to nosnaptrim > > If this helps, you might need to upgrade to pacific, because you are hit by > the pg dups bug. > > See: https://www.clyso.com/blog/how-to-identify-osds-affected-by-pg-dup-bug/ > > > Mit freundlichen Grüßen > - Boris Behrens > >>> Am 06.12.2023 um 19:01 schrieb Peter <peter...@raksmart.com>: >>> >> Dear all, >> >> >> I am reaching out regarding an issue with our Ceph cluster that has been >> recurring every six hours. Upon investigating the problem using the "ceph >> daemon dump_historic_slow_ops" command, I observed that the issue appears to >> be related to slow operations, specifically getting stuck at "Waiting for RW >> Locks." The wait times often range from one to two seconds. >> >> Our cluster use SAS SSD disks from Samsung for the storage pool in question. >> While these disks are of high quality and should provide sufficient speed, >> the problem persists. The slow ops occurrence is consistent every six hours. >> >> I would greatly appreciate any insights or suggestions you may have to >> address and resolve this issue. If there are specific optimizations or >> configurations that could improve the situation, please advise. >> >> >> below are some output: >> >> root@lasas003:~# ceph -v >> ceph version 15.2.17 (542df8d06ef24dbddcf4994db16bcc4c89c9ec2d) octopus >> (stable) >> >> >> "events": [ >> >> { >> "event": "initiated", >> "time": "2023-12-06T08:34:18.501644-0800", >> "duration": 0 >> }, >> { >> "event": "throttled", >> "time": "2023-12-06T08:34:18.501644-0800", >> "duration": 3.067e-06 >> }, >> { >> "event": "header_read", >> "time": "2023-12-06T08:34:18.501647-0800", >> "duration": 3.5429999999999998e-06 >> }, >> { >> "event": "all_read", >> "time": "2023-12-06T08:34:18.501650-0800", >> "duration": 9.3399999999999997e-07 >> }, >> { >> "event": "dispatched", >> "time": "2023-12-06T08:34:18.501651-0800", >> "duration": 3.2830000000000002e-06 >> }, >> { >> "event": "queued_for_pg", >> "time": "2023-12-06T08:34:18.501654-0800", >> "duration": 1.3819939990000001 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:19.883648-0800", >> "duration": 5.7980000000000002e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:19.883654-0800", >> "duration": 4.2484711649999998 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:24.132125-0800", >> "duration": 1.0667e-05 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:24.132136-0800", >> "duration": 2.1593527840000002 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:26.291489-0800", >> "duration": 3.292e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:26.291492-0800", >> "duration": 0.43918164700000001 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:26.730674-0800", >> "duration": 5.1529999999999996e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:26.730679-0800", >> "duration": 1.0531516869999999 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:27.783831-0800", >> "duration": 5.1329999999999998e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:27.783836-0800", >> "duration": 1.232525088 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.016361-0800", >> "duration": 3.844e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.016365-0800", >> "duration": 0.0051385700000000003 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.021503-0800", >> "duration": 4.7600000000000002e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.021508-0800", >> "duration": 0.0092808779999999994 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.030789-0800", >> "duration": 4.0690000000000003e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.030793-0800", >> "duration": 0.55757725499999999 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.588370-0800", >> "duration": 5.5060000000000003e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.588376-0800", >> "duration": 0.0064168929999999999 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.594793-0800", >> "duration": 7.0690000000000004e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.594800-0800", >> "duration": 0.0026404089999999998 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.597440-0800", >> "duration": 3.3440000000000001e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.597444-0800", >> "duration": 0.0051126670000000004 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.602556-0800", >> "duration": 5.0200000000000002e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.602561-0800", >> "duration": 0.0040569960000000002 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.606618-0800", >> "duration": 5.0989999999999998e-06 >> }, >> { >> "event": "waiting for rw locks", >> "time": "2023-12-06T08:34:29.606623-0800", >> "duration": 0.0068874100000000001 >> }, >> { >> "event": "reached_pg", >> "time": "2023-12-06T08:34:29.613511-0800", >> "duration": 1.4636e-05 >> }, >> { >> "event": "started", >> "time": "2023-12-06T08:34:29.613525-0800", >> "duration": 0.00028943699999999997 >> }, >> { >> "event": "done", >> "time": "2023-12-06T08:34:29.613815-0800", >> "duration": 11.112171102 >> } >> >> >> Thank you in advance for your assistance. >> _______________________________________________ >> ceph-users mailing list -- ceph-users@ceph.io >> To unsubscribe send an email to ceph-users-le...@ceph.io _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
