Thanks for details. What is the best suitable pool type for object storage? Thanks Swami On Sun, Jan 24, 2016 at 8:58 PM, Nick Fisk <nick@xxxxxxxxxx> wrote: > Yes that seems about right. > > Erasure coding works similar to Raid5/6 so data will be striped, whereas > replicated pools are simple copies of data. When you write to a 3x > replicated pool you are having to write 3 times as much and so performance > is lower. When writing to an erasure coded pool (k=8 m=2 for example) you > are only having to write 20% worth of redundancy data. > > As for reads, in an ideal world both would have similar performance. But > currently erasure coded pools require all chunks to be returned to satisfy a > read request, even if the request is smaller than a whole object. Also the > read request hits the primary OSD and then it forwards the remaining > requests onto all the other OSD's which hold the remaining erasure chunks. > Another factor is that in erasure pools, as the object is split into smaller > chunks you will be getting less performance from spinning disks as disks > give the most bandwidth when doing 4MB+ IO's. > > All of these reasons tend to make reading slightly slower. > >> -----Original Message----- >> From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of >> M Ranga Swami Reddy >> Sent: 24 January 2016 15:09 >> To: ceph-users <ceph-users@xxxxxxxx> >> Subject: Performance - pool with erasure/replicated type pool >> >> Hello, >> I have 2 pools as below: >> >> 1. pool1 with erasure type >> 2. pool2 with replicated type >> >> I ran the "rados bench" with above 2 pool and the results came as below: >> >> - Read performance - around 60% better for replicated type pool ie pool2 >> - Write performance - around 50 % better for erasure type pool ie pool1. >> >> Can someone help me, if the above is correct behavior with ceph? >> Or do I miss something here? >> >> Thanks >> Swami >> _______________________________________________ >> 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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