Hi Götz, Please see my response below. On Tue, Apr 30, 2024 at 7:39 PM Pierre Riteau <pierre@xxxxxxxxxxxx> wrote: > Hi Götz, > > You can change the value of osd_max_backfills (for all OSDs or specific > ones) using `ceph config`, but you need > enable osd_mclock_override_recovery_settings. See > > https://docs.ceph.com/en/quincy/rados/configuration/mclock-config-ref/#steps-to-modify-mclock-max-backfills-recovery-limits > for more information. > > Did the suggestion from Pierre help improve the backfilling rate? With the mClock scheduler, this is the correct way of modifying the value of osd_max_backfills and osd_recovery_max_active. As to the observation of slower backfills, this is expected with the 'balanced' and 'high_client_ops' mClock profiles (see allocations here <https://docs.ceph.com/en/latest/rados/configuration/mclock-config-ref/#built-in-profiles>). This is due to backfill operation being classified as background best-effort service and a lower priority assigned to backfill operations when compared to degraded recoveries. Degraded recovery (or background recovery service) is given higher priority as there's a higher risk of data unavailability in case other OSDs in the cluster go down. Backfill operations are assigned lower priority since it just involves data movement. If the 'high_recovery_ops' profile coupled with increasing the above config parameters is still not enough to improve the backfilling rate, then the cluster must be examined to see if there are other competing services like degraded recoveries, client ops etc. that could affect the backfilling rate. The ceph status output should give an idea about this. -Sridhar _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
 |