Am 21.08.2018 um 12:03 schrieb Stefan Priebe - Profihost AG: > > Am 21.08.2018 um 11:56 schrieb Dan van der Ster: >> On Tue, Aug 21, 2018 at 11:54 AM Stefan Priebe - Profihost AG >> <s.priebe@xxxxxxxxxxxx> wrote: >>> >>> Am 21.08.2018 um 11:47 schrieb Dan van der Ster: >>>> On Mon, Aug 20, 2018 at 10:45 PM Stefan Priebe - Profihost AG >>>> <s.priebe@xxxxxxxxxxxx> wrote: >>>>> >>>>> >>>>> Am 20.08.2018 um 22:38 schrieb Dan van der Ster: >>>>>> On Mon, Aug 20, 2018 at 10:19 PM Stefan Priebe - Profihost AG >>>>>> <s.priebe@xxxxxxxxxxxx> wrote: >>>>>>> >>>>>>> >>>>>>> Am 20.08.2018 um 21:52 schrieb Sage Weil: >>>>>>>> On Mon, 20 Aug 2018, Stefan Priebe - Profihost AG wrote: >>>>>>>>> Hello, >>>>>>>>> >>>>>>>>> since loic seems to have left ceph development and his wunderful crush >>>>>>>>> optimization tool isn'T working anymore i'm trying to get a good >>>>>>>>> distribution with the ceph balancer. >>>>>>>>> >>>>>>>>> Sadly it does not work as good as i want. >>>>>>>>> >>>>>>>>> # ceph osd df | sort -k8 >>>>>>>>> >>>>>>>>> show 75 to 83% Usage which is 8% difference which is too much for me. >>>>>>>>> I'm optimization by bytes. >>>>>>>>> >>>>>>>>> # ceph balancer eval >>>>>>>>> current cluster score 0.005420 (lower is better) >>>>>>>>> >>>>>>>>> # ceph balancer eval $OPT_NAME >>>>>>>>> plan spriebe_2018-08-20_19:36 final score 0.005456 (lower is better) >>>>>>>>> >>>>>>>>> I'm unable to optimize further ;-( Is there any chance to optimize >>>>>>>>> further even in case of more rebelancing? >>>>>>>> >>>>>>>> The scoring that the balancer module is doing is currently a hybrid of pg >>>>>>>> count, bytes, and object count. Picking a single metric might help a bit >>>>>>>> (as those 3 things are not always perfectly aligned). >>>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> ok i found a bug in the balancer code which seems to be present in all >>>>>>> releases. >>>>>>> >>>>>>> 861 best_ws = next_ws >>>>>>> 862 best_ow = next_ow >>>>>>> >>>>>>> >>>>>>> should be: >>>>>>> >>>>>>> 861 best_ws = copy.deepcopy(next_ws) >>>>>>> 862 best_ow = copy.deepcopy(next_ow) >>>>>>> >>>>>>> otherwise it does not use the best but the last. >>>>>> >>>>>> Interesting... does that change improve things? >>>>> >>>>> It fixes the following (mgr debug output): >>>>> 2018-08-20 22:33:46.078525 7f2fbc3b6700 0 mgr[balancer] Step result >>>>> score 0.001152 -> 0.001180, misplacing 0.000912 >>>>> 2018-08-20 22:33:46.078574 7f2fbc3b6700 0 mgr[balancer] Score got >>>>> worse, taking another step >>>>> 2018-08-20 22:33:46.078770 7f2fbc3b6700 0 mgr[balancer] Balancing root >>>>> default (pools ['cephstor2']) by bytes >>>>> 2018-08-20 22:33:46.156326 7f2fbc3b6700 0 mgr[balancer] Step result >>>>> score 0.001152 -> 0.001180, misplacing 0.000912 >>>>> 2018-08-20 22:33:46.156374 7f2fbc3b6700 0 mgr[balancer] Score got >>>>> worse, taking another step >>>>> 2018-08-20 22:33:46.156581 7f2fbc3b6700 0 mgr[balancer] Balancing root >>>>> default (pools ['cephstor2']) by bytes >>>>> 2018-08-20 22:33:46.233818 7f2fbc3b6700 0 mgr[balancer] Step result >>>>> score 0.001152 -> 0.001180, misplacing 0.000912 >>>>> 2018-08-20 22:33:46.233868 7f2fbc3b6700 0 mgr[balancer] Score got >>>>> worse, taking another step >>>>> 2018-08-20 22:33:46.234043 7f2fbc3b6700 0 mgr[balancer] Balancing root >>>>> default (pools ['cephstor2']) by bytes >>>>> 2018-08-20 22:33:46.313212 7f2fbc3b6700 0 mgr[balancer] Step result >>>>> score 0.001152 -> 0.001180, misplacing 0.000912 >>>>> 2018-08-20 22:33:46.313714 7f2fbc3b6700 0 mgr[balancer] Score got >>>>> worse, trying smaller step 0.000244 >>>>> 2018-08-20 22:33:46.313887 7f2fbc3b6700 0 mgr[balancer] Balancing root >>>>> default (pools ['cephstor2']) by bytes >>>>> 2018-08-20 22:33:46.391586 7f2fbc3b6700 0 mgr[balancer] Step result >>>>> score 0.001152 -> 0.001152, misplacing 0.001141 >>>>> 2018-08-20 22:33:46.393374 7f2fbc3b6700 0 mgr[balancer] Balancing root >>>>> default (pools ['cephstor2']) by bytes >>>>> 2018-08-20 22:33:46.473956 7f2fbc3b6700 0 mgr[balancer] Step result >>>>> score 0.001152 -> 0.001180, misplacing 0.000912 >>>>> 2018-08-20 22:33:46.474001 7f2fbc3b6700 0 mgr[balancer] Score got >>>>> worse, taking another step >>>>> 2018-08-20 22:33:46.474046 7f2fbc3b6700 0 mgr[balancer] Success, score >>>>> 0.001155 -> 0.001152 >>>>> >>>>> BUT: >>>>> # ceph balancer eval myplan >>>>> plan myplan final score 0.001180 (lower is better) >>>>> >>>>> So the final plan does NOT contain the expected optimization. The >>>>> deepcopy fixes it. >>>>> >>>>> After: >>>>> # ceph balancer eval myplan >>>>> plan myplan final score 0.001152 (lower is better) >>>>> >>>> >>>> OK that looks like a bug. Did you create a tracker or PR? >>> >>> No not yet. Should i create a PR on github with the fix? >> >> Yeah, probably tracker first (requesting luminous,mimic backports), >> then a PR on master with "Fixes: tracker..." > > Will do but can't find a create button in the tracker. I've opened > several reports in the past but right now it seems a can't create a ticket. http://tracker.ceph.com/projects/ceph/issues/new => 403 You are not authorized to access this page. > Stefan > >> >> -- dan >> >> >>> >>>> -- Dan >>>> >>>> >>>>>> >>>>>> Also, if most of your data is in one pool you can try ceph balancer >>>>>> eval <pool-name> >>>>> >>>>> Already tried this doesn't help much. >>>>> >>>>> Greets, >>>>> Stefan >>>>> >>>>> >>>>>> -- dan >>>>>> >>>>>>> >>>>>>> I'm also using this one: >>>>>>> https://github.com/ceph/ceph/pull/20665/commits/c161a74ad6cf006cd9b33b40fd7705b67c170615 >>>>>>> >>>>>>> to optimize by bytes only. >>>>>>> >>>>>>> Greets, >>>>>>> Stefan _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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