Thank you. Yes, selection of an optimal pool type is not eas for object storage. Thanks Swami On Mon, Jan 25, 2016 at 1:32 PM, Nick Fisk <nick@xxxxxxxxxx> wrote: > For object storage I'm not sure there is a best each have their own > advantages and disadvantages. > > If you need the space efficiency, then erasure is probably the best > candidate. > > >> -----Original Message----- >> From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of >> M Ranga Swami Reddy >> Sent: 24 January 2016 16:09 >> To: Nick Fisk <nick@xxxxxxxxxx> >> Cc: ceph-users <ceph-users@xxxxxxxx> >> Subject: Re: Performance - pool with erasure/replicated type >> pool >> >> 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 > _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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