On Wed, Nov 30, 2016 at 04:22:10PM +0800, Zhen Cao wrote: > Hi, > I am reading the RADOS paper,but i could not understand why more PGs > per OSD result in a more balanced distribution.I konw the mapping > procedure between oid and osd，but it is neverless difficult to > understand for me. > Thanks for your help! In a nuthshell - because each PG corresponds to multiple objects. And because of this, it is possible that some PGs will aggregate more objects than other PGs, resulting in lack of acutal balance. Also see here: http://docs.ceph.com/docs/jewel/rados/operations/placement-groups/ -- Piotr Dałek branch@xxxxxxxxxxxxxxxx http://blog.predictor.org.pl -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
