Hi, It might be usefull to benchmark your individual OSD's first. Wiki: http://ceph.newdream.net/wiki/Troubleshooting#OSD_performance There might be a slow OSD in your cluster which slows down the cluster. With some test with the Ceph filesystem i was able to reach speeds up to 150MB/sec (dd with conv=sync) writing to my Ceph filesystem. Haven't tried RBD yet on the cluster, but in my previous setup i was reaching about 30 ~ 35MB/sec with RBD. Wido On Tue, 2010-08-10 at 10:18 +0200, Ulrich Oelmann wrote: > Hi there, > > I don't think that Xiaoguang saw the speed of 30-60 MB/s because of cache > effects as the speed should be in the order of at least some hundred MB/s > then. Do you agree? > > Could perhaps someone having an rbd-setup running confirm or reject > Xiaoguangs measurements? > > Best regards > Ulrich > > > -----Ursprüngliche Nachricht----- > Von: Haifeng Liu <haifeng@xxxxxxxxxxxxx> > Gesendet: Aug 10, 2010 7:46:52 AM > An: "ceph-devel@xxxxxxxxxxxxxxx" <ceph-devel@xxxxxxxxxxxxxxx> > Betreff: Re: RBD performance is not good > > >Xiaoguang, > > > >This should be a normal result – the client’s pagecache buffered the write > >when you dd onto a ceph fs, while no buffering when dd to a rbd. What do you > >think? > > > >Thanks > >-haifeng > > > > > >On 8/10/10 11:23 AM, "Xiaoguang Liu" wrote: > > > >> on my 2-ods-node cluster, dd can only reach 13MB/s on rbd device. this > >> is much lower than what I expected. > >> I can get 30-60 MB/s on a ceph filesystem over the same cluster. > >> > >> any idea? > >> > >> > >> > >> > >> [root@ceph-1 ~]# dd if=/dev/zero of=/dev/rbd0 bs=1M count=5000 > >> 5000+0 records in > >> 5000+0 records out > >> 5242880000 bytes (5.2 GB) copied, 391.508 s, 13.4 MB/s > >> -- > >> 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 > >> > > > >N�����r��y���b�X��ǧv�^�){.n�+���z�]z���{ay� ʇڙ�,j��f���h���z� �w��� ���j:+v���w�j�m��������zZ+��ݢj"�� > -- > 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 -- 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
