Hi Özkan, in our case, we tried online compaction first, and it helped to resolve the issue completely. I did first test with a single OSD daemon (i.e. only online compaction of that single OSD), and checked that the load of that daemon went down significantly (that was while snaptrims with high sleep value were still going on). Then, I went in batches of 10 % of the cluster's OSDs, and they finished rather fast (few minutes) so I could do it without a downtime, actually.
In older threads on this list, snaptrim issues which seemed similar (but not
clearly related to an upgrade) required more heavy operations (either offline
compaction or OSD recreation).
Since online compaction is comparatibely "cheap", I'd always try this first, in
my case, each OSD took less than 2-3 minutes for this, but of course your mileage may
vary.
Cheers,
Oliver
Am 23.08.24 um 17:42 schrieb Özkan Göksu:
Hello Oliver. Thank you so much for the answer! I was thinking of re-creating the OSD's but if you are sure the compaction is the solution here then it's worth to try. I'm planning to shutdown all the VM's and when the cluster is safe then I will try OSD compaction. May I learn did you do online compaction or offline? Because I have 2 side and I can shutdown 1 entire rack and do the offline compaction and do the same thing other side when its done. What do you think? Regards. Oliver Freyermuth <freyerm...@physik.uni-bonn.de <mailto:freyerm...@physik.uni-bonn.de>>, 23 Ağu 2024 Cum, 18:06 tarihinde şunu yazdı: Hi Özkan, FWIW, we observed something similar after upgrading from Mimic => Nautilus => Octopus and starting to trim snapshots after. The size of our cluster was a bit smaller, but the effect was the same: When snapshot trimming started, OSDs went into high load and RBD I/O was extremely slow. We tried to use: ceph tell osd.* injectargs '--osd-snap-trim-sleep 10' first, which helped, but of course snapshots kept piling up. Finally, we performed only RocksDB compactions via: for A in {0..5}; do ceph tell osd.$A compact | sed 's/^/'$A': /' & done for some batches of OSDs, and their load went down heavily. Finally, after we'd churned through all OSDs, I/O load was low again, and we could go back to the default: ceph tell osd.* injectargs '--osd-snap-trim-sleep 0' After this, the situation has stabilized for us. So my guess would be that the RocksDBs grew too much after the OMAP format conversion and the compaction shrank them again. Maybe that also helps in your case? Interestingly, we did not observe this on other clusters (one mainly for CephFS, another one with mirrored RBD volumes), which took the same upgrade path. Cheers, Oliver Am 23.08.24 um 16:46 schrieb Özkan Göksu: > Hello folks. > > We have a ceph cluster and we have 2000+ RBD drives on 20 nodes. > > We upgraded the cluster from 14.2.16 to 15.2.14 and after the upgrade we > started to see snap trim issues. > Without the "nosnaptrim" flag, the system is not usable right now. > > I think the problem is because of the omap conversion at Octopus upgrade. > > Note that the first time each OSD starts, it will do a format conversion to > improve the accounting for “omap” data. This may take a few minutes to as > much as a few hours (for an HDD with lots of omap data). You can disable > this automatic conversion with: > > What should I do to solve this problem? > > Thanks. > _______________________________________________ > ceph-users mailing list -- ceph-users@ceph.io <mailto:ceph-users@ceph.io> > To unsubscribe send an email to ceph-users-le...@ceph.io <mailto:ceph-users-le...@ceph.io>-- Oliver FreyermuthUniversität Bonn Physikalisches Institut, Raum 1.047 Nußallee 12 53115 Bonn -- Tel.: +49 228 73 2367 Fax: +49 228 73 7869 --
-- Oliver Freyermuth Universität Bonn Physikalisches Institut, Raum 1.047 Nußallee 12 53115 Bonn -- Tel.: +49 228 73 2367 Fax: +49 228 73 7869 --
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