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. 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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