On 07/03/2014 04:32 PM, VELARTIS Philipp D?rhammer wrote: > HI, > > Ceph.conf: > osd journal size = 15360 > rbd cache = true > rbd cache size = 2147483648 > rbd cache max dirty = 1073741824 > rbd cache max dirty age = 100 > osd recovery max active = 1 > osd max backfills = 1 > osd mkfs options xfs = "-f -i size=2048" > osd mount options xfs = "rw,noatime,nobarrier,logbsize=256k,logbufs=8,inode64,allocsize=4M" > osd op threads = 8 > > so it should be 8 threads? > How many threads are you using with rados bench? Don't touch the op threads from the start, usually the default is just fine. > All 3 machines have more or less the same disk load at the same time. > also the disks: > sdb 35.56 87.10 6849.09 617310 48540806 > sdc 26.75 72.62 5148.58 514701 36488992 > sdd 35.15 53.48 6802.57 378993 48211141 > sde 31.04 79.04 6208.48 560141 44000710 > sdf 32.79 38.35 6238.28 271805 44211891 > sdg 31.67 77.84 5987.45 551680 42434167 > sdh 32.95 51.29 6315.76 363533 44761001 > sdi 31.67 56.93 5956.29 403478 42213336 > sdj 35.83 77.82 6929.31 551501 49109354 > sdk 36.86 73.84 7291.00 523345 51672704 > sdl 36.02 112.90 7040.47 800177 49897132 > sdm 33.25 38.02 6455.05 269446 45748178 > sdn 33.52 39.10 6645.19 277101 47095696 > sdo 33.26 46.22 6388.20 327541 45274394 > sdp 33.38 74.12 6480.62 525325 45929369 > > > the question is: is this a poor performance to get max 500mb/write with 45 disks and replica 2 or should I expect this? > You should be able to get more as long as the I/O is done in parallel. Wido > > -----Urspr?ngliche Nachricht----- > Von: ceph-users [mailto:ceph-users-bounces at lists.ceph.com] Im Auftrag von Wido den Hollander > Gesendet: Donnerstag, 03. Juli 2014 15:22 > An: ceph-users at lists.ceph.com > Betreff: Re: [ceph-users] write performance per disk > > On 07/03/2014 03:11 PM, VELARTIS Philipp D?rhammer wrote: >> Hi, >> >> I have a ceph cluster setup (with 45 sata disk journal on disks) and >> get only 450mb/sec writes seq (maximum playing around with threads in >> rados >> bench) with replica of 2 >> > > How many threads? > >> Which is about ~20Mb writes per disk (what y see in atop also) >> theoretically with replica2 and having journals on disk should be 45 X >> 100mb (sata) / 2 (replica) / 2 (journal writes) which makes it 1125 >> satas in reality have 120mb/sec so the theoretical output should be more. >> >> I would expect to have between 40-50mb/sec for each sata disk >> >> Can somebody confirm that he can reach this speed with a setup with >> journals on the satas (with journals on ssd speed should be 100mb per disk)? >> or does ceph only give about ? of the speed for a disk? (and not the ? >> as expected because of journals) >> > > Did you verify how much each machine is doing? It could be that the data is not distributed evenly and that on a certain machine the drives are doing 50MB/sec. > >> My setup is 3 servers with: 2 x 2.6ghz xeons, 128gb ram 15 satas for >> ceph (and ssds for system) 1 x 10gig for external traffic, 1 x 10gig >> for osd traffic with reads I can saturate the network but writes is >> far away. And I would expect at least to saturate the 10gig with >> sequential writes also >> > > Should be possible, but with 3 servers the data distribution might not be optimal causing a lower write performance. > > I've seen 10Gbit write performance on multiple clusters without any problems. > >> Thank you >> >> >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users at lists.ceph.com >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > > > -- > Wido den Hollander > Ceph consultant and trainer > 42on B.V. > > Phone: +31 (0)20 700 9902 > Skype: contact42on > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > -- Wido den Hollander 42on B.V. Ceph trainer and consultant Phone: +31 (0)20 700 9902 Skype: contact42on
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