Hi all, I have a technical question about scrub scheduling. I replaced a disk and it is back-filling slowly. We have set osd_scrub_during_recovery = true and still observe that scrub times continuously increase (number of PGs not scrubbed in time is continuously increasing). Investigating the situation it looks like any OSD that has a PG in states "backfill_wait" or "backfilling" is preventing scrubs to be scheduled on PGs it is a member of. However, it seems it is not quite like that.
On the one hand I have never seen a PG in a state like "active+scrubbing+remapped+backfilling", so backfilling PGs at least never seem to scrub. On the other hand, it seems like more PGs are scrubbed than would be eligible if *all* OSDs with a remapped PG on it would refuse scrubs. It looks like something in between "only OSDs with a backfilling PG block requests for scrub reservations" and "all OSDs with a PG in states backfilling or backfill_wait block requests for scrub reservations". Does the position in the backfill reservation queue play a role? If anyone has insight into how scrub reservations are granted and when not in the situation of an OSD backfilling that would be great. My naive interpretation of "osd_scrub_during_recovery = true" was that scrubs proceed as if no backfill was going on. This, however, is clearly not the case. Having an answer to my question above would help me a lot to get an idea when things will go back to normal. Thanks a lot and best regards, ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14 _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
