Hi Kenneth, On 03/06/2014 14:11, Kenneth Waegeman wrote:> > ----- Message from Loic Dachary <l...@dachary.org> --------- > Date: Fri, 23 May 2014 07:37:22 +0200 > From: Loic Dachary <l...@dachary.org> > Subject: Re: [ceph-users] recommendations for erasure coded pools and profile > question > To: Kenneth Waegeman <kenneth.waege...@ugent.be>, ceph-users > <ceph-users@lists.ceph.com> > > >> Hi Kenneth, >> >> In the case of erasure coded pools, the "Replicas" should be replaced by >> "K+M". >> >> $ ceph osd erasure-code-profile get myprofile >> k=2 >> m=1 >> plugin=jerasure >> technique=reed_sol_van >> ruleset-failure-domain=osd >> >> You have K+M=3 >> >> I proposed a fix to the documentation https://github.com/ceph/ceph/pull/1856 >> . If I understand correctly, this formula is more a helper than an exact >> count, otherwise it would be embedded into Ceph and the operator would not >> have to think about it. > > Thanks Loic also for this! > > Since it is not an exact count, in which situations should we not use this > formula? I guess mainly when planning to add more pools on the same OSDs (and > thus 'saving' PGs for future use). Are there other considerations? > > Also, inside Ceph, when using only/mainly EC pools, I get a health warning : > HEALTH_WARN too few pgs per osd (15 < min 20), which is indeed true when e.g > having only one EC pool with eg K+M=10: > Total PGs = OSD * 100 / 10 -> 10 PGs per OSD. Should we ignore this?
I think you can ignore this warning. Cheers > > Cheers! > Kenneth > >> >> ceph --format json osd dump >> >> will show you which pool is using which profile. >> >> Cheers >> >> On 22/05/2014 14:38, Kenneth Waegeman wrote: >>> Hi, >>> >>> How can we apply the recommendations of the number of placement groups onto >>> erasure-coded pools? >>> >>> (OSDs * 100) >>> Total PGs = ------------ >>> Replicas >>> >>> Should we set replica = 1, or should it be set against some EC parameters? >>> >>> >>> Also a question about the EC profiles. >>> I know you can show them with 'ceph osd erasure-code-profile ls', >>> get or set parameters with 'ceph osd erasure-code-profile get/set', and >>> create a pool with it with 'ceph osd create ecpool pg pgn erasure >>> <profile>. But can you also list which pool has which profile? >>> >>> Thanks! >>> >>> Kenneth >>> >>> _______________________________________________ >>> ceph-users mailing list >>> ceph-users@lists.ceph.com >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> -- >> Loïc Dachary, Artisan Logiciel Libre > > > ----- End message from Loic Dachary <l...@dachary.org> ----- > -- Loïc Dachary, Artisan Logiciel Libre
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