tried changing scheduler from deadline to noop also upgraded to Gaint and btrfs filesystem,downgraded kernel to 3.16 from 3.16-3 not much difference
dd if=/dev/zero of=hi bs=4k count=25000 oflag=direct 25000+0 records in 25000+0 records out 102400000 bytes (102 MB) copied, 94.691 s, 1.1 MB/s Earlier on a vmware setup i was getting ~850 KBps and now even on physical server with SSD drives its just over 1MBps.I doubt some serious configuration issues. Tried iperf between 3 servers all are showing 9 Gbps,tried icmp with different packet size ,no fragmentation. i also noticed that out of 9 osd 5 are 850 EVO and 4 are 840 EVO.I believe this will not cause this much drop in performance. Thanks for any help On Sat, Feb 28, 2015 at 6:49 PM, Alexandre DERUMIER <aderum...@odiso.com> wrote: > As optimisation, > > try to set ioscheduler to noop, > > and also enable rbd_cache=true. (It's really helping for for sequential > writes) > > but your results seem quite low, 926kb/s with 4k, it's only 200io/s. > > check if you don't have any big network latencies, or mtu fragementation > problem. > > Maybe also try to bench with fio, with more parallel jobs. > > > > > ----- Mail original ----- > De: "mad Engineer" <themadengin...@gmail.com> > À: "Philippe Schwarz" <p...@schwarz-fr.net> > Cc: "ceph-users" <ceph-users@lists.ceph.com> > Envoyé: Samedi 28 Février 2015 13:06:59 > Objet: Re: [ceph-users] Extreme slowness in SSD cluster with 3 nodes and 9 > OSD with 3.16-3 kernel > > Thanks for the reply Philippe,we were using these disks in our NAS,now > it looks like i am in big trouble :-( > > On Sat, Feb 28, 2015 at 5:02 PM, Philippe Schwarz <p...@schwarz-fr.net> > wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > Le 28/02/2015 12:19, mad Engineer a écrit : > >> Hello All, > >> > >> I am trying ceph-firefly 0.80.8 > >> (69eaad7f8308f21573c604f121956e64679a52a7) with 9 OSD ,all Samsung > >> SSD 850 EVO on 3 servers with 24 G RAM,16 cores @2.27 Ghz Ubuntu > >> 14.04 LTS with 3.16-3 kernel.All are connected to 10G ports with > >> maximum MTU.There are no extra disks for journaling and also there > >> are no separate network for replication and data transfer.All 3 > >> nodes are also hosting monitoring process.Operating system runs on > >> SATA disk. > >> > >> When doing a sequential benchmark using "dd" on RBD, mounted on > >> client as ext4 its taking 110s to write 100Mb data at an average > >> speed of 926Kbps. > >> > >> time dd if=/dev/zero of=hello bs=4k count=25000 oflag=direct > >> 25000+0 records in 25000+0 records out 102400000 bytes (102 MB) > >> copied, 110.582 s, 926 kB/s > >> > >> real 1m50.585s user 0m0.106s sys 0m2.233s > >> > >> While doing this directly on ssd mount point shows: > >> > >> time dd if=/dev/zero of=hello bs=4k count=25000 oflag=direct > >> 25000+0 records in 25000+0 records out 102400000 bytes (102 MB) > >> copied, 1.38567 s, 73.9 MB/s > >> > >> OSDs are in XFS with these extra arguments : > >> > >> rw,noatime,inode64,logbsize=256k,delaylog,allocsize=4M > >> > >> ceph.conf > >> > >> [global] fsid = 7d889081-7826-439c-9fe5-d4e57480d9be > >> mon_initial_members = ceph1, ceph2, ceph3 mon_host = > >> 10.99.10.118,10.99.10.119,10.99.10.120 auth_cluster_required = > >> cephx auth_service_required = cephx auth_client_required = cephx > >> filestore_xattr_use_omap = true osd_pool_default_size = 2 > >> osd_pool_default_min_size = 2 osd_pool_default_pg_num = 450 > >> osd_pool_default_pgp_num = 450 max_open_files = 131072 > >> > >> [osd] osd_mkfs_type = xfs osd_op_threads = 8 osd_disk_threads = 4 > >> osd_mount_options_xfs = > >> "rw,noatime,inode64,logbsize=256k,delaylog,allocsize=4M" > >> > >> > >> on our traditional storage with Full SAS disk, same "dd" completes > >> in 16s with an average write speed of 6Mbps. > >> > >> Rados bench: > >> > >> rados bench -p rbd 10 write Maintaining 16 concurrent writes of > >> 4194304 bytes for up to 10 seconds or 0 objects Object prefix: > >> benchmark_data_ceph1_2977 sec Cur ops started finished avg MB/s > >> cur MB/s last lat avg lat 0 0 0 0 > >> 0 0 - 0 1 16 94 78 > >> 311.821 312 0.041228 0.140132 2 16 192 176 > >> 351.866 392 0.106294 0.175055 3 16 275 259 > >> 345.216 332 0.076795 0.166036 4 16 302 286 > >> 285.912 108 0.043888 0.196419 5 16 395 379 > >> 303.11 372 0.126033 0.207488 6 16 501 485 > >> 323.242 424 0.125972 0.194559 7 16 621 605 > >> 345.621 480 0.194155 0.183123 8 16 730 714 > >> 356.903 436 0.086678 0.176099 9 16 814 798 > >> 354.572 336 0.081567 0.174786 10 16 832 > >> 816 326.313 72 0.037431 0.182355 11 16 833 > >> 817 297.013 4 0.533326 0.182784 Total time run: > >> 11.489068 Total writes made: 833 Write size: > >> 4194304 Bandwidth (MB/sec): 290.015 > >> > >> Stddev Bandwidth: 175.723 Max bandwidth (MB/sec): 480 Min > >> bandwidth (MB/sec): 0 Average Latency: 0.220582 Stddev > >> Latency: 0.343697 Max latency: 2.85104 Min > >> latency: 0.035381 > >> > >> Our ultimate aim is to replace existing SAN with ceph,but for that > >> it should meet minimum 8000 iops.Can any one help me with this,OSD > >> are SSD,CPU has good clock speed,backend network is good but still > >> we are not able to extract full capability of SSD disks. > >> > >> > >> > >> Thanks, > > > > Hi, i'm new to ceph so, don't consider my words as holy truth. > > > > It seems that Samsung 840 (so i assume 850) are crappy for ceph : > > > > MTBF : > > > http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-November/044258.html > > Bandwidth > > : > http://lists.ceph.com/pipermail/ceph-users-ceph.com/2014-December/045247.html > > > > And according to a confirmed user of Ceph/ProxmoX, Samsung SSDs should > > be avoided if possible in ceph storage. > > > > Apart from that, it seems there was an limitation in ceph for the use > > of the complete bandwidth available in SSDs; but i think with less > > than 1Mb/s you haven't hit this limit. > > > > I remind you that i'm not a ceph-guru (far from that, indeed), so feel > > free to disagree; i'm on the way to improve my knowledge. > > > > Best regards. > > > > > > > > > > -----BEGIN PGP SIGNATURE----- > > Version: GnuPG v1 > > > > iEYEARECAAYFAlTxp0UACgkQlhqCFkbqHRb5+wCgrXCM3VsnVE6PCbbpOmQXCXbr > > 8u0An2BUgZWismSK0PxbwVDOD5+/UWik > > =0o0v > > -----END PGP SIGNATURE----- > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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