Our journal writes are actually sequential. Could you send FIO results for sequential 4k writes osd.0's journal and osd.1's journal? -Sam On Thu, Mar 22, 2012 at 5:21 AM, Andrey Korolyov <andrey@xxxxxxx> wrote: > FIO output for journal partition, directio enabled, seems good(same > results for ext4 on other single sata disks). > > random-rw: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=sync, iodepth=2 > Starting 1 process > Jobs: 1 (f=1): [w] [100.0% done] [0K/3219K /s] [0/786 iops] [eta 00m:00s] > random-rw: (groupid=0, jobs=1): err= 0: pid=21926 > write: io=163840KB, bw=2327KB/s, iops=581, runt= 70403msec > clat (usec): min=122, max=441551, avg=1714.52, stdev=7565.04 > bw (KB/s) : min= 552, max= 3880, per=100.61%, avg=2341.23, stdev=480.05 > cpu : usr=0.42%, sys=1.34%, ctx=40976, majf=0, minf=42 > IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% > complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% > issued r/w: total=0/40960, short=0/0 > lat (usec): 250=31.70%, 500=0.68%, 750=0.10%, 1000=0.63% > lat (msec): 2=41.31%, 4=20.91%, 10=4.40%, 20=0.17%, 50=0.07% > lat (msec): 500=0.04% > > > > On Thu, Mar 22, 2012 at 1:20 AM, Samuel Just <sam.just@xxxxxxxxxxxxx> wrote: >> (CCing the list) >> >> So, the problem isn't the bandwidth. Before we respond to the client, >> we write the operation to the journal. In this case, that operation >> is taking >1s per operation on osd.1. Both rbd and rados bench will >> only allow a limited number of ops in flight at a time, so this >> latency is killing your throughput. For comparison, the latency for >> writing to the journal on osd.0 is < .3s. Can you measure direct io >> latency for writes to your osd.1 journal file? >> -Sam >> >> On Wed, Mar 21, 2012 at 1:56 PM, Andrey Korolyov <andrey@xxxxxxx> wrote: >>> Oh, you may confuse with Zabbix metrics - y-axis means Megabytes/s, >>> not Megabits. >>> >>> On Thu, Mar 22, 2012 at 12:53 AM, Andrey Korolyov <andrey@xxxxxxx> wrote: >>>> [global] >>>> log dir = /ceph/out >>>> log_file = "" >>>> logger dir = /ceph/log >>>> pid file = /ceph/out/$type$id.pid >>>> [mds] >>>> pid file = /ceph/out/$name.pid >>>> lockdep = 1 >>>> mds log max segments = 2 >>>> [osd] >>>> lockdep = 1 >>>> filestore_xattr_use_omap = 1 >>>> osd data = /ceph/dev/osd$id >>>> osd journal = /ceph/meta/journal >>>> osd journal size = 100 >>>> [mon] >>>> lockdep = 1 >>>> mon data = /ceph/dev/mon$id >>>> [mon.0] >>>> host = 172.20.1.32 >>>> mon addr = 172.20.1.32:6789 >>>> [mon.1] >>>> host = 172.20.1.33 >>>> mon addr = 172.20.1.33:6789 >>>> [mon.2] >>>> host = 172.20.1.35 >>>> mon addr = 172.20.1.35:6789 >>>> [osd.0] >>>> host = 172.20.1.32 >>>> [osd.1] >>>> host = 172.20.1.33 >>>> [mds.a] >>>> host = 172.20.1.32 >>>> >>>> /dev/sda1 on /ceph type ext4 (rw,barrier=0,user_xattr) >>>> /dev/mapper/system-cephmeta on /ceph/meta type ext4 (rw,barrier=0,user_xattr) >>>> Simple performance tests on those fs shows ~133Mb/s for /ceph and >>>> metadata/. Also both machines do not hold anything else which may >>>> impact osd. >>>> >>>> Also please note of following: >>>> >>>> http://i.imgur.com/ZgFdO.png >>>> >>>> First two peaks are related to running rados bench, then goes cluster >>>> recreation, automated debian install and final peaks are dd test. >>>> Surely I can have more precise graphs, but current one probably enough >>>> to state a situation - rbd utilizing about a quarter of possible >>>> bandwidth(if we can count rados bench as 100%). >>>> >>>> On Thu, Mar 22, 2012 at 12:39 AM, Samuel Just <sam.just@xxxxxxxxxxxxx> wrote: >>>>> Hmm, there seem to be writes taking as long as 1.5s to hit journal on >>>>> osd.1... Could you post your ceph.conf? Might there be a problem >>>>> with the osd.1 journal disk? >>>>> -Sam >>>>> >>>>> On Wed, Mar 21, 2012 at 1:25 PM, Andrey Korolyov <andrey@xxxxxxx> wrote: >>>>>> Oh, sorry - they probably inherited rights from log files, fixed. >>>>>> >>>>>> On Thu, Mar 22, 2012 at 12:17 AM, Samuel Just <sam.just@xxxxxxxxxxxxx> wrote: >>>>>>> I get 403 Forbidden when I try to download any of the files. >>>>>>> -Sam >>>>>>> >>>>>>> On Wed, Mar 21, 2012 at 11:51 AM, Andrey Korolyov <andrey@xxxxxxx> wrote: >>>>>>>> http://xdel.ru/downloads/ceph-logs/ >>>>>>>> >>>>>>>> 1/ contains logs related to bench initiated at the osd0 machine and 2/ >>>>>>>> - at osd1. >>>>>>>> >>>>>>>> On Wed, Mar 21, 2012 at 8:54 PM, Samuel Just <sam.just@xxxxxxxxxxxxx> wrote: >>>>>>>>> Hmm, I'm seeing some very high latency on ops sent to osd.1. Can you >>>>>>>>> post osd.1's logs? >>>>>>>>> -Sam >>>>>>>>> >>>>>>>>> On Wed, Mar 21, 2012 at 3:51 AM, Andrey Korolyov <andrey@xxxxxxx> wrote: >>>>>>>>>> Here, please: http://xdel.ru/downloads/ceph.log.gz >>>>>>>>>> >>>>>>>>>> Sometimes 'cur MB/s ' shows zero during rados bench, even if any debug >>>>>>>>>> output disabled and log_file set to the empty value, hope it`s okay. >>>>>>>>>> >>>>>>>>>> On Wed, Mar 21, 2012 at 2:36 AM, Samuel Just <sam.just@xxxxxxxxxxxxx> wrote: >>>>>>>>>>> Can you set osd and filestore debugging to 20, restart the osds, run >>>>>>>>>>> rados bench as before, and post the logs? >>>>>>>>>>> -Sam Just >>>>>>>>>>> >>>>>>>>>>> On Tue, Mar 20, 2012 at 1:37 PM, Andrey Korolyov <andrey@xxxxxxx> wrote: >>>>>>>>>>>> rados bench 60 write -p data >>>>>>>>>>>> <skip> >>>>>>>>>>>> Total time run: 61.217676 >>>>>>>>>>>> Total writes made: 989 >>>>>>>>>>>> Write size: 4194304 >>>>>>>>>>>> Bandwidth (MB/sec): 64.622 >>>>>>>>>>>> >>>>>>>>>>>> Average Latency: 0.989608 >>>>>>>>>>>> Max latency: 2.21701 >>>>>>>>>>>> Min latency: 0.255315 >>>>>>>>>>>> >>>>>>>>>>>> Here a snip from osd log, seems write size is okay. >>>>>>>>>>>> >>>>>>>>>>>> 2012-03-21 00:00:39.397066 7fdda86a7700 osd.0 10 pg[0.58( v 10'83 >>>>>>>>>>>> (0'0,10'83] n=50 ec=1 les/c 9/9 8/8/6) [0,1] r=0 lpr=8 mlcod 10'82 >>>>>>>>>>>> active+clean] removing repgather(0x31b5360 applying 10'83 rep_tid=597 >>>>>>>>>>>> wfack= wfdisk= op=osd_op(client.4599.0:2533 rb.0.2.000000000040 [write >>>>>>>>>>>> 1220608~4096] 0.17eb9fd8) v4) >>>>>>>>>>>> 2012-03-21 00:00:39.397086 7fdda86a7700 osd.0 10 pg[0.58( v 10'83 >>>>>>>>>>>> (0'0,10'83] n=50 ec=1 les/c 9/9 8/8/6) [0,1] r=0 lpr=8 mlcod 10'82 >>>>>>>>>>>> active+clean] q front is repgather(0x31b5360 applying 10'83 >>>>>>>>>>>> rep_tid=597 wfack= wfdisk= op=osd_op(client.4599.0:2533 >>>>>>>>>>>> rb.0.2.000000000040 [write 1220608~4096] 0.17eb9fd8) v4) >>>>>>>>>>>> >>>>>>>>>>>> Sorry for my previous question about rbd chunks, it was really stupid :) >>>>>>>>>>>> >>>>>>>>>>>> On Mon, Mar 19, 2012 at 10:40 PM, Josh Durgin <josh.durgin@xxxxxxxxxxxxx> wrote: >>>>>>>>>>>>> On 03/19/2012 11:13 AM, Andrey Korolyov wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>> Nope, I`m using KVM for rbd guests. Surely I`ve been noticed that Sage >>>>>>>>>>>>>> mentioned too small value and I`ve changed it to 64M before posting >>>>>>>>>>>>>> previous message with no success - both 8M and this value cause a >>>>>>>>>>>>>> performance drop. When I tried to wrote small amount of data that can >>>>>>>>>>>>>> be compared to writeback cache size(both on raw device and ext3 with >>>>>>>>>>>>>> sync option), following results were made: >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> I just want to clarify that the writeback window isn't a full writeback >>>>>>>>>>>>> cache - it doesn't affect reads, and does not help with request merging etc. >>>>>>>>>>>>> It simply allows a bunch of writes to be in flight while acking the write to >>>>>>>>>>>>> the guest immediately. We're working on a full-fledged writeback cache that >>>>>>>>>>>>> to replace the writeback window. >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>>> dd if=/dev/zero of=/var/img.1 bs=10M count=10 oflag=direct (almost >>>>>>>>>>>>>> same without oflag there and in the following samples) >>>>>>>>>>>>>> 10+0 records in >>>>>>>>>>>>>> 10+0 records out >>>>>>>>>>>>>> 104857600 bytes (105 MB) copied, 0.864404 s, 121 MB/s >>>>>>>>>>>>>> dd if=/dev/zero of=/var/img.1 bs=10M count=20 oflag=direct >>>>>>>>>>>>>> 20+0 records in >>>>>>>>>>>>>> 20+0 records out >>>>>>>>>>>>>> 209715200 bytes (210 MB) copied, 6.67271 s, 31.4 MB/s >>>>>>>>>>>>>> dd if=/dev/zero of=/var/img.1 bs=10M count=30 oflag=direct >>>>>>>>>>>>>> 30+0 records in >>>>>>>>>>>>>> 30+0 records out >>>>>>>>>>>>>> 314572800 bytes (315 MB) copied, 12.4806 s, 25.2 MB/s >>>>>>>>>>>>>> >>>>>>>>>>>>>> and so on. Reference test with bs=1M and count=2000 has slightly worse >>>>>>>>>>>>>> results _with_ writeback cache than without, as I`ve mentioned before. >>>>>>>>>>>>>> Here the bench results, they`re almost equal on both nodes: >>>>>>>>>>>>>> >>>>>>>>>>>>>> bench: wrote 1024 MB in blocks of 4096 KB in 9.037468 sec at 113 MB/sec >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> One thing to check is the size of the writes that are actually being sent by >>>>>>>>>>>>> rbd. The guest is probably splitting them into relatively small (128 or >>>>>>>>>>>>> 256k) writes. Ideally it would be sending 4k writes, and this should be a >>>>>>>>>>>>> lot faster. >>>>>>>>>>>>> >>>>>>>>>>>>> You can see the writes being sent by adding debug_ms=1 to the client or osd. >>>>>>>>>>>>> The format is osd_op(.*[write OFFSET~LENGTH]). >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>>> Also, because I`ve not mentioned it before, network performance is >>>>>>>>>>>>>> enough to hold fair gigabit connectivity with MTU 1500. Seems that it >>>>>>>>>>>>>> is not interrupt problem or something like it - even if ceph-osd, >>>>>>>>>>>>>> ethernet card queues and kvm instance pinned to different sets of >>>>>>>>>>>>>> cores, nothing changes. >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Mon, Mar 19, 2012 at 8:59 PM, Greg Farnum >>>>>>>>>>>>>> <gregory.farnum@xxxxxxxxxxxxx> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> It sounds like maybe you're using Xen? The "rbd writeback window" option >>>>>>>>>>>>>>> only works for userspace rbd implementations (eg, KVM). >>>>>>>>>>>>>>> If you are using KVM, you probably want 81920000 (~80MB) rather than >>>>>>>>>>>>>>> 8192000 (~8MB). >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> What options are you running dd with? If you run a rados bench from both >>>>>>>>>>>>>>> machines, what do the results look like? >>>>>>>>>>>>>>> Also, can you do the ceph osd bench on each of your OSDs, please? >>>>>>>>>>>>>>> (http://ceph.newdream.net/wiki/Troubleshooting#OSD_performance) >>>>>>>>>>>>>>> -Greg >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Monday, March 19, 2012 at 6:46 AM, Andrey Korolyov wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> More strangely, writing speed drops down by fifteen percent when this >>>>>>>>>>>>>>>> option was set in vm` config(instead of result from >>>>>>>>>>>>>>>> http://www.mail-archive.com/ceph-devel@xxxxxxxxxxxxxxx/msg03685.html). >>>>>>>>>>>>>>>> As I mentioned, I`m using 0.43, but due to crashed osds, ceph has been >>>>>>>>>>>>>>>> recompiled with e43546dee9246773ffd6877b4f9495f1ec61cd55 and >>>>>>>>>>>>>>>> 1468d95101adfad44247016a1399aab6b86708d2 - both cases caused crashes >>>>>>>>>>>>>>>> under heavy load. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Sun, Mar 18, 2012 at 10:22 PM, Sage Weil<sage@xxxxxxxxxxxx >>>>>>>>>>>>>>>> (mailto:sage@xxxxxxxxxxxx)> wrote: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> On Sat, 17 Mar 2012, Andrey Korolyov wrote: >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Hi, >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> I`ve did some performance tests at the following configuration: >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> mon0, osd0 and mon1, osd1 - two twelve-core r410 with 32G ram, mon2 - >>>>>>>>>>>>>>>>>> dom0 with three dedicated cores and 1.5G, mostly idle. First three >>>>>>>>>>>>>>>>>> disks on each r410 arranged into raid0 and holds osd data when fourth >>>>>>>>>>>>>>>>>> holds os and osd` journal partition, all ceph-related stuff mounted on >>>>>>>>>>>>>>>>>> the ext4 without barriers. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Firstly, I`ve noticed about a difference of benchmark performance and >>>>>>>>>>>>>>>>>> write speed through rbd from small kvm instance running on one of >>>>>>>>>>>>>>>>>> first two machines - when bench gave me about 110Mb/s, writing zeros >>>>>>>>>>>>>>>>>> to raw block device inside vm with dd was at top speed about 45 mb/s, >>>>>>>>>>>>>>>>>> for vm`fs (ext4 with default options) performance drops to ~23Mb/s. >>>>>>>>>>>>>>>>>> Things get worse, when I`ve started second vm at second host and tried >>>>>>>>>>>>>>>>>> to continue same dd tests simultaneously - performance fairly divided >>>>>>>>>>>>>>>>>> by half for each instance :). Enabling jumbo frames, playing with cpu >>>>>>>>>>>>>>>>>> affinity for ceph and vm instances and trying different TCP congestion >>>>>>>>>>>>>>>>>> protocols gave no effect at all - with DCTCP I have slightly smoother >>>>>>>>>>>>>>>>>> network load graph and that`s all. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Can ml please suggest anything to try to improve performance? >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Can you try setting >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> rbd writeback window = 8192000 >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> or similar, and see what kind of effect that has? I suspect it'll speed >>>>>>>>>>>>>>>>> up dd; I'm less sure about ext3. >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Thanks! >>>>>>>>>>>>>>>>> sage >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> ceph-0.43, libvirt-0.9.8, qemu-1.0.0, kernel 3.2 >>>>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>>>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" >>>>>>>>>>>>>>>>>> in >>>>>>>>>>>>>>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>>>>>>>>>>>>>>> (mailto: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 >>>>>>>>>>>>>>>> (mailto: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 >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>>>> 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 -- 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
