Besides what Mark and Greg said it could be due to additional hops through network devices. What network devices are you using, what is the network topology and does your CRUSH map reflect the network topology? On Oct 21, 2013 9:43 AM, "Gregory Farnum" <g...@inktank.com> wrote:
> On Mon, Oct 21, 2013 at 7:13 AM, Guang Yang <yguan...@yahoo.com> wrote: > > Dear ceph-users, > > Recently I deployed a ceph cluster with RadosGW, from a small one (24 > OSDs) to a much bigger one (330 OSDs). > > > > When using rados bench to test the small cluster (24 OSDs), it showed > the average latency was around 3ms (object size is 5K), while for the > larger one (330 OSDs), the average latency was around 7ms (object size 5K), > twice comparing the small cluster. > > > > The OSD within the two cluster have the same configuration, SAS disk, > and two partitions for one disk, one for journal and the other for > metadata. > > > > For PG numbers, the small cluster tested with the pool having 100 PGs, > and for the large cluster, the pool has 43333 PGs (as I will to further > scale the cluster, so I choose a much large PG). > > > > Does my test result make sense? Like when the PG number and OSD > increase, the latency might drop? > > Besides what Mark said, can you describe your test in a little more > detail? Writing/reading, length of time, number of objects, etc. > -Greg > Software Engineer #42 @ http://inktank.com | http://ceph.com > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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