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? > -- 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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