Am 12.07.2013 um 21:23 schrieb Mark Nelson <mark.nelson@xxxxxxxxxxx>: > On 07/12/2013 02:19 PM, Stefan Priebe - Profihost AG wrote: >> Right now I have 4096. 36*100/3 => 1200. As recovery take ages I thought this might be the reason. > > Are you seeing any craziness on the mons? What could this be? Nothing noticed. Stefan > >> >> Stefan >> >> This mail was sent with my iPhone. >> >> Am 12.07.2013 um 17:03 schrieb Mark Nelson <mark.nelson@xxxxxxxxxxx>: >> >>> On 07/12/2013 09:53 AM, Gandalf Corvotempesta wrote: >>>> 2013/7/12 Mark Nelson <mark.nelson@xxxxxxxxxxx>: >>>>> At large numbers of PGs it may not matter very much, but I don't think it >>>>> would hurt either! >>>>> >>>>> Basically this has to do with how ceph_stable_mod works. At >>>>> non-power-of-two values, the bucket counts aren't even, but that's only a >>>>> small part of the story and may ultimately only have a small effect on the >>>>> distribution unless the PG count is small. >>>> >>>> In case of 12 OSDs for each node, and a cluster made with 18 storage >>>> nodes are you suggesting: >>>> >>>> (12*18*100) / 3 = 7200 PGs, that rounded to an exponent of 2 means 8192 ? >>> >>> Well, our official recommendation on the website is PGS = OSDS * 100 / replicas. I think the thought is that with sufficient numbers of OSDs the behaviour of ceph_stable_mod shouldn't matter (much). At some point I'd like to do a little more involved of an analysis to see how PG distribution changes, but for now I wouldn't really expect a dramatic difference between 7200 and 8192 PGs. >>> >>> Mark >>> _______________________________________________ >>> ceph-users mailing list >>> ceph-users@xxxxxxxxxxxxxx >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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