I received a few suggestions, and resolved my issue. Anthony D'Atri suggested mclock (newer than my nautilus version), adding "--osd_recovery_max_single_start 1” (didn’t seem to take), “osd_op_queue_cut_off=high” (which I didn’t get to checking), and pgremapper (from github). Pgremapper did the trick to cancel the backfill which had been initiated by an unfortunate OSD name-changing sequence. Big winner, achieved EXACTLY what I needed, which was to undo an unfortunate recalculation of placement groups. Before: 310842802/17308319325 objects misplaced (1.796%) Ran: pgremapper cancel-backfill --yes After: 421709/17308356309 objects misplaced (0.002%) The “before” scenario was causing over 10GiB/s of backfill traffic. The “after” scenario was a very cool 300-400MiB/s, entirely within the realm of sanity. The cluster is temporarily split between two datacenters, being physically lifted and shifted over a period of a month. Alex Gorbachev also suggested setting osd-recovery-sleep. That was probably the solution I was looking for to throttle backfill operations at the beginning, and I’ll be keeping that in my toolbox, as well. As always, I’m HUGELY appreciative of the community response. I learned a lot in the process, had an outage-inducing scenario rectified very quickly, and got back to work. Thanks so much! Happy to answer any followup questions and return the favor when I can. From: Rice, Christian <crice@pandora.com> Date: Wednesday, March 8, 2023 at 3:57 PM To: ceph-users <ceph-users@ceph.io> Subject: [EXTERNAL] [ceph-users] Trying to throttle global backfill I have a large number of misplaced objects, and I have all osd settings to “1” already: sudo ceph tell osd.\* injectargs '--osd_max_backfills=1 --osd_recovery_max_active=1 --osd_recovery_op_priority=1' How can I slow it down even more? The cluster is too large, it’s impacting other network traffic 😉 _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-leave@ceph.io