> > > Sorry I got confused! Do you mean that both recovery_op_priority and recovery_priority should be 63 to have a slow recovery? recovery_priority is set per-pool to rank recovery relative to other pools. This is not related to your questions. https://docs.ceph.com/en/latest/rados/operations/placement-groups/#prioritize-backfill-recovery-of-a-placement-group-s > If so why the client op priority is default 63 and recovery op is 3? This means that by default recovery op is more prioritize than client op! Exactly the opposite. Client ops take priority over recovery ops. And various other ops have priorities as described in the document I pointed you to. > In the link you share (Github one) It says that if priority is higher as an integer it will mean that it prioritizes others! > Can you please clarify this, please? I think this should be documented as well in Ceph because in general, I think it means that a higher integer number means higher priority than a lower integer number and so if we set recovery op priority to 63 it will do recovery too fast and will impact the overall cluster performance! That’s why it is commonly suggested to set recovery_op_priority to 1 if you need to slow down recovery as well as the other values I sent you. https://docs.ceph.com/en/latest/rados/configuration/osd-config-ref/#operations > Thanks. > > On Wed, Dec 2, 2020 at 10:25 PM Anthony D'Atri <anthony.datri@xxxxxxxxx> wrote: > FWIW https://github.com/ceph/ceph/blob/master/doc/dev/osd_internals/backfill_reservation.rst has some discussion of op priorities, though client ops aren’t mentioned explicitly. If you like, enter a documentation tracker and tag me and I’ll look into adding that. > > > On Dec 2, 2020, at 9:56 AM, Stefan Kooman <stefan@xxxxxx> wrote: > > > > On 12/2/20 5:36 PM, Seena Fallah wrote: > >> If it uses PriorityQueue <https://en.wikipedia.org/wiki/Priority_queue#:~:text=In%20computer%20science%2C%20a%20priority,an%20element%20with%20low%20priority.> Data Structure an element with high priority should be dequeued before an element with low priority. > > > > - osd client op priority > > The priority set for client operations. It is relative to osd recovery op priority. > > > > The op priority for client io is (default) 63. So with that regard a lower value should be lower priority. Same as the PriorityQueue you linked. > > > > A simple example would be a great way to take out any confusion. I'll try to attend a "Docubetter" meeting to discuss this. > > > > Gr. Stefan > > _______________________________________________ > > ceph-users mailing list -- ceph-users@xxxxxxx > > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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