Hi, > On 27 May 2025, at 10:54, Szabo, Istvan (Agoda) <istvan.sz...@agoda.com> > wrote: > > Some status update, it's finished with 3x times stop and start the rebalance. > Would be interesting to know what is the extra data generated on the new osds > during remapped pg allocation at rebalance. I stopped when the osd reaches > 89% full, I let it rest for 2 days, it went down to 64%. After restart filled > up again to 89%, I stopped for a day and it went down to 71%, then final > restart finished. > > I have some concerns regarding the PG allocator algorithm in > Octopus—specifically, there may be issues either within the algorithm itself > or potentially due to anomalous data generated during rebalancing. I'm not > certain if this has been addressed or optimized in more recent releases. > Currently, our maximum PG size is 60GB. However, during rebalancing, it > appears that PGs are being allocated without a thorough check on their sizes. > Upon reviewing the number of PGs on our OSDs, I’m seeing values between 60 > and 70. This implies that if 60–70 PGs, each sized at 60GB, are assigned to a > single OSD, the OSD will inevitably reach full capacity. A more balanced > approach would be to distribute smaller PGs as well, not just the largest > ones. It is possible that the balancer intervenes at a later stage but not > when has remapped pgs, this is not entirely clear from the current behavior.
In Octopus since this [1] patch, the OSD really care about RAW sizes. You should understand, that after PG moved to another OSD, - PG should switch her state to Stray. Only Stray PG's will be removed eventually. OSD delete one object in second for single PG. So, if you have many PG for remove and wanna increase delete speed you should look to the osd_delete_sleep_ option k [1] https://tracker.ceph.com/issues/50601 _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
