Although the documentation is not great, and open to interpretation, there is a pg calculator here http://ceph.com/pgcalc/. With it you should be able to simulate your use case, and generate number based on your scenario.
On Mon, Jan 26, 2015 at 8:00 PM, Italo Santos <okd...@gmail.com> wrote: > Thanks for your answer. > > But what I’d like to understand is if this numbers are per pool bases or > per cluster bases? If this number were per cluster bases I’ll plan on > cluster deploy how much pools I’d like to have on that cluster and their > replicas > > Regards. > > *Italo Santos* > http://italosantos.com.br/ > > On Saturday, January 17, 2015 at 07:04, lidc...@redhat.com wrote: > > Here are a few values commonly used: > > - Less than 5 OSDs set pg_num to 128 > - Between 5 and 10 OSDs set pg_num to 512 > - Between 10 and 50 OSDs set pg_num to 4096 > - If you have more than 50 OSDs, you need to understand the tradeoffs > and how to calculate the pg_num value by yourself > > But i think 10 OSD is to small for rados cluster. > > > *From:* Italo Santos <okd...@gmail.com> > *Date:* 2015-01-17 05:00 > *To:* ceph-users <ceph-users@lists.ceph.com> > *Subject:* [ceph-users] Total number PGs using multiple pools > Hello, > > Into placement groups documentation > <http://ceph.com/docs/giant/rados/operations/placement-groups/> we have > the message bellow: > > “*When using multiple data pools for storing objects, you need to ensure > that you balance the number of placement groups per pool with the number of > placement groups per OSD so that you arrive at a reasonable total number of > placement groups that provides reasonably low variance per OSD without > taxing system resources or making the peering process too slow.*” > > This means that, if I have a cluster with 10 OSD and 3 pools with size = 3 > each pool can have only ~111 PGs? > > Ex.: (100 * 10 OSDs) / 3 replicas = 333 PGs / 3 pools = 111 PGS per pool > > I don't know if reasoning is right… I’ll glad for any help. > > Regards. > > *Italo Santos* > http://italosantos.com.br/ > > > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >
_______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
