You are getting a fair amount of reads on the disks whilst doing these writes. You're not using cache tiering are you?
> -----Original Message----- > From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of > Lincoln Bryant > Sent: 17 September 2015 17:42 > To: ceph-users@lists.ceph.com > Subject: Re: [ceph-users] Ceph cluster NO read / write performance :: Ops > are blocked > > Hello again, > > Well, I disabled offloads on the NIC -- didn’t work for me. I also tried > setting > net.ipv4.tcp_moderate_rcvbuf = 0 as suggested elsewhere in the thread to > no avail. > > Today I was watching iostat on an OSD box ('iostat -xm 5') when the cluster > got into “slow” state: > > Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz > avgqu-sz > await svctm %util > sdb 0.00 13.57 84.23 167.47 0.45 2.78 26.26 > 2.06 8.18 3.85 > 96.93 > sdc 0.00 46.71 5.59 289.22 0.03 2.54 17.85 > 3.18 10.77 0.97 > 28.72 > sdd 0.00 16.57 45.11 91.62 0.25 0.55 12.01 > 0.75 5.51 2.45 > 33.47 > sde 0.00 13.57 6.99 143.31 0.03 2.53 34.97 > 1.99 13.27 2.12 > 31.86 > sdf 0.00 18.76 4.99 158.48 0.10 1.09 14.88 > 1.26 7.69 1.24 > 20.26 > sdg 0.00 25.55 81.64 237.52 0.44 2.89 21.36 > 4.14 12.99 2.58 > 82.22 > sdh 0.00 89.42 16.17 492.42 0.09 3.81 15.69 > 17.12 33.66 0.73 > 36.95 > sdi 0.00 20.16 17.76 189.62 0.10 1.67 17.46 > 3.45 16.63 1.57 > 32.55 > sdj 0.00 31.54 0.00 185.23 0.00 1.91 21.15 > 3.33 18.00 0.03 > 0.62 > sdk 0.00 26.15 2.40 133.33 0.01 0.84 12.79 > 1.07 7.87 0.85 > 11.58 > sdl 0.00 25.55 9.38 123.95 0.05 1.15 18.44 > 0.50 3.74 1.58 > 21.10 > sdm 0.00 6.39 92.61 47.11 0.47 0.26 10.65 > 1.27 9.07 6.92 > 96.73 > > The %util is rather high on some disks, but I’m not an expert at looking at > iostat so I’m not sure how worrisome this is. Does anything here stand out to > anyone? > > At the time of that iostat, Ceph was reporting a lot of blocked ops on the OSD > associated with sde (as well as about 30 other OSDs), but it doesn’t look all > that busy. Some simple ‘dd’ tests seem to indicate the disk is fine. > > Similarly, iotop seems OK on this host: > > TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND > 472477 be/4 root 0.00 B/s 5.59 M/s 0.00 % 0.57 % ceph-osd -i 111 > --pid- > file /var/run/ceph/osd.111.pid -c /etc/ceph/ceph.conf --cluster ceph > 470621 be/4 root 0.00 B/s 10.09 M/s 0.00 % 0.40 % ceph-osd -i 111 > --pid- > file /var/run/ceph/osd.111.pid -c /etc/ceph/ceph.conf --cluster ceph > 3495447 be/4 root 0.00 B/s 272.19 K/s 0.00 % 0.36 % ceph-osd -i 114 > -- > pid-file /var/run/ceph/osd.114.pid -c /etc/ceph/ceph.conf --cluster ceph > 3488389 be/4 root 0.00 B/s 596.80 K/s 0.00 % 0.16 % ceph-osd -i 109 -- > pid-file /var/run/ceph/osd.109.pid -c /etc/ceph/ceph.conf --cluster ceph > 3488060 be/4 root 0.00 B/s 600.83 K/s 0.00 % 0.15 % ceph-osd -i 108 > -- > pid-file /var/run/ceph/osd.108.pid -c /etc/ceph/ceph.conf --cluster ceph > 3505573 be/4 root 0.00 B/s 528.25 K/s 0.00 % 0.10 % ceph-osd -i 119 > -- > pid-file /var/run/ceph/osd.119.pid -c /etc/ceph/ceph.conf --cluster ceph > 3495434 be/4 root 0.00 B/s 2.02 K/s 0.00 % 0.10 % ceph-osd -i 114 > --pid- > file /var/run/ceph/osd.114.pid -c /etc/ceph/ceph.conf --cluster ceph > 3502327 be/4 root 0.00 B/s 506.07 K/s 0.00 % 0.09 % ceph-osd -i 118 > -- > pid-file /var/run/ceph/osd.118.pid -c /etc/ceph/ceph.conf --cluster ceph > 3489100 be/4 root 0.00 B/s 106.86 K/s 0.00 % 0.09 % ceph-osd -i 110 > -- > pid-file /var/run/ceph/osd.110.pid -c /etc/ceph/ceph.conf --cluster ceph > 3496631 be/4 root 0.00 B/s 229.85 K/s 0.00 % 0.05 % ceph-osd -i 115 > -- > pid-file /var/run/ceph/osd.115.pid -c /etc/ceph/ceph.conf --cluster ceph > 3505561 be/4 root 0.00 B/s 2.02 K/s 0.00 % 0.03 % ceph-osd -i 119 -- > pid-file /var/run/ceph/osd.119.pid -c /etc/ceph/ceph.conf --cluster ceph > 3488059 be/4 root 0.00 B/s 2.02 K/s 0.00 % 0.03 % ceph-osd -i 108 > --pid- > file /var/run/ceph/osd.108.pid -c /etc/ceph/ceph.conf --cluster ceph > 3488391 be/4 root 46.37 K/s 431.47 K/s 0.00 % 0.02 % ceph-osd -i 109 > -- > pid-file /var/run/ceph/osd.109.pid -c /etc/ceph/ceph.conf --cluster ceph > 3500639 be/4 root 0.00 B/s 221.78 K/s 0.00 % 0.02 % ceph-osd -i 117 > -- > pid-file /var/run/ceph/osd.117.pid -c /etc/ceph/ceph.conf --cluster ceph > 3488392 be/4 root 34.28 K/s 185.49 K/s 0.00 % 0.02 % ceph-osd -i 109 > -- > pid-file /var/run/ceph/osd.109.pid -c /etc/ceph/ceph.conf --cluster ceph > 3488062 be/4 root 4.03 K/s 66.54 K/s 0.00 % 0.02 % ceph-osd -i 108 > --pid- > file /var/run/ceph/osd.108.pid -c /etc/ceph/ceph.conf --cluster ceph > > These are all 6TB seagates in single-disk RAID 0 on a PERC H730 Mini > controller. > > I did try removing the disk with 20k non-medium errors, but that didn’t seem > to help. > > Thanks for any insight! > > Cheers, > Lincoln Bryant > > > On Sep 9, 2015, at 1:09 PM, Lincoln Bryant <linco...@uchicago.edu> wrote: > > > > Hi Jan, > > > > I’ll take a look at all of those things and report back (hopefully :)) > > > > I did try setting all of my OSDs to writethrough instead of writeback on the > controller, which was significantly more consistent in performance (from > 1100MB/s down to 300MB/s, but still occasionally dropping to 0MB/s). Still > plenty of blocked ops. > > > > I was wondering if not-so-nicely failing OSD(s) might be the cause. My > controller (PERC H730 Mini) seems frustratingly terse with SMART > information, but at least one disk has a “Non-medium error count” of over > 20,000.. > > > > I’ll try disabling offloads as well. > > > > Thanks much for the suggestions! > > > > Cheers, > > Lincoln > > > >> On Sep 9, 2015, at 3:59 AM, Jan Schermer <j...@schermer.cz> wrote: > >> > >> Just to recapitulate - the nodes are doing "nothing" when it drops to zero? > Not flushing something to drives (iostat)? Not cleaning pagecache (kswapd > and similiar)? Not out of any type of memory (slab, min_free_kbytes)? Not > network link errors, no bad checksums (those are hard to spot, though)? > >> > >> Unless you find something I suggest you try disabling offloads on the NICs > and see if the problem goes away. > >> > >> Jan > >> > >>> On 08 Sep 2015, at 18:26, Lincoln Bryant <linco...@uchicago.edu> wrote: > >>> > >>> For whatever it’s worth, my problem has returned and is very similar to > yours. Still trying to figure out what’s going on over here. > >>> > >>> Performance is nice for a few seconds, then goes to 0. This is a > >>> similar setup to yours (12 OSDs per box, Scientific Linux 6, Ceph > >>> 0.94.3, etc) > >>> > >>> 384 16 29520 29504 307.287 1188 0.0492006 0.208259 > >>> 385 16 29813 29797 309.532 1172 0.0469708 0.206731 > >>> 386 16 30105 30089 311.756 1168 0.0375764 0.205189 > >>> 387 16 30401 30385 314.009 1184 0.036142 0.203791 > >>> 388 16 30695 30679 316.231 1176 0.0372316 0.202355 > >>> 389 16 30987 30971 318.42 1168 0.0660476 0.200962 > >>> 390 16 31282 31266 320.628 1180 0.0358611 0.199548 > >>> 391 16 31568 31552 322.734 1144 0.0405166 0.198132 > >>> 392 16 31857 31841 324.859 1156 0.0360826 0.196679 > >>> 393 16 32090 32074 326.404 932 0.0416869 0.19549 > >>> 394 16 32205 32189 326.743 460 0.0251877 0.194896 > >>> 395 16 32302 32286 326.897 388 0.0280574 0.194395 > >>> 396 16 32348 32332 326.537 184 0.0256821 0.194157 > >>> 397 16 32385 32369 326.087 148 0.0254342 0.193965 > >>> 398 16 32424 32408 325.659 156 0.0263006 0.193763 > >>> 399 16 32445 32429 325.054 84 0.0233839 0.193655 > >>> 2015-09-08 11:22:31.940164 min lat: 0.0165045 max lat: 67.6184 avg lat: > 0.193655 > >>> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat > >>> 400 16 32445 32429 324.241 0 - 0.193655 > >>> 401 16 32445 32429 323.433 0 - 0.193655 > >>> 402 16 32445 32429 322.628 0 - 0.193655 > >>> 403 16 32445 32429 321.828 0 - 0.193655 > >>> 404 16 32445 32429 321.031 0 - 0.193655 > >>> 405 16 32445 32429 320.238 0 - 0.193655 > >>> 406 16 32445 32429 319.45 0 - 0.193655 > >>> 407 16 32445 32429 318.665 0 - 0.193655 > >>> > >>> needless to say, very strange. > >>> > >>> —Lincoln > >>> > >>> > >>>> On Sep 7, 2015, at 3:35 PM, Vickey Singh > <vickey.singh22...@gmail.com> wrote: > >>>> > >>>> Adding ceph-users. > >>>> > >>>> On Mon, Sep 7, 2015 at 11:31 PM, Vickey Singh > <vickey.singh22...@gmail.com> wrote: > >>>> > >>>> > >>>> On Mon, Sep 7, 2015 at 10:04 PM, Udo Lembke > <ulem...@polarzone.de> wrote: > >>>> Hi Vickey, > >>>> Thanks for your time in replying to my problem. > >>>> > >>>> I had the same rados bench output after changing the motherboard of > the monitor node with the lowest IP... > >>>> Due to the new mainboard, I assume the hw-clock was wrong during > startup. Ceph health show no errors, but all VMs aren't able to do IO (very > high load on the VMs - but no traffic). > >>>> I stopped the mon, but this don't changed anything. I had to restart all > other mons to get IO again. After that I started the first mon also (with the > right time now) and all worked fine again... > >>>> > >>>> Thanks i will try to restart all OSD / MONS and report back , if it > >>>> solves my problem > >>>> > >>>> Another posibility: > >>>> Do you use journal on SSDs? Perhaps the SSDs can't write to garbage > collection? > >>>> > >>>> No i don't have journals on SSD , they are on the same OSD disk. > >>>> > >>>> > >>>> > >>>> Udo > >>>> > >>>> > >>>> On 07.09.2015 16:36, Vickey Singh wrote: > >>>>> Dear Experts > >>>>> > >>>>> Can someone please help me , why my cluster is not able write data. > >>>>> > >>>>> See the below output cur MB/S is 0 and Avg MB/s is decreasing. > >>>>> > >>>>> > >>>>> Ceph Hammer 0.94.2 > >>>>> CentOS 6 (3.10.69-1) > >>>>> > >>>>> The Ceph status says OPS are blocked , i have tried checking , > >>>>> what all i know > >>>>> > >>>>> - System resources ( CPU , net, disk , memory ) -- All normal > >>>>> - 10G network for public and cluster network -- no saturation > >>>>> - Add disks are physically healthy > >>>>> - No messages in /var/log/messages OR dmesg > >>>>> - Tried restarting OSD which are blocking operation , but no luck > >>>>> - Tried writing through RBD and Rados bench , both are giving > >>>>> same problemm > >>>>> > >>>>> Please help me to fix this problem. > >>>>> > >>>>> # rados bench -p rbd 60 write > >>>>> Maintaining 16 concurrent writes of 4194304 bytes for up to 60 > >>>>> seconds or 0 objects Object prefix: benchmark_data_stor1_1791844 > >>>>> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat > >>>>> 0 0 0 0 0 0 - 0 > >>>>> 1 16 125 109 435.873 436 0.022076 0.0697864 > >>>>> 2 16 139 123 245.948 56 0.246578 0.0674407 > >>>>> 3 16 139 123 163.969 0 - 0.0674407 > >>>>> 4 16 139 123 122.978 0 - 0.0674407 > >>>>> 5 16 139 123 98.383 0 - 0.0674407 > >>>>> 6 16 139 123 81.9865 0 - 0.0674407 > >>>>> 7 16 139 123 70.2747 0 - 0.0674407 > >>>>> 8 16 139 123 61.4903 0 - 0.0674407 > >>>>> 9 16 139 123 54.6582 0 - 0.0674407 > >>>>> 10 16 139 123 49.1924 0 - 0.0674407 > >>>>> 11 16 139 123 44.7201 0 - 0.0674407 > >>>>> 12 16 139 123 40.9934 0 - 0.0674407 > >>>>> 13 16 139 123 37.8401 0 - 0.0674407 > >>>>> 14 16 139 123 35.1373 0 - 0.0674407 > >>>>> 15 16 139 123 32.7949 0 - 0.0674407 > >>>>> 16 16 139 123 30.7451 0 - 0.0674407 > >>>>> 17 16 139 123 28.9364 0 - 0.0674407 > >>>>> 18 16 139 123 27.3289 0 - 0.0674407 > >>>>> 19 16 139 123 25.8905 0 - 0.0674407 > >>>>> 2015-09-07 15:54:52.694071min lat: 0.022076 max lat: 0.46117 avg lat: > 0.0674407 > >>>>> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat > >>>>> 20 16 139 123 24.596 0 - 0.0674407 > >>>>> 21 16 139 123 23.4247 0 - 0.0674407 > >>>>> 22 16 139 123 22.36 0 - 0.0674407 > >>>>> 23 16 139 123 21.3878 0 - 0.0674407 > >>>>> 24 16 139 123 20.4966 0 - 0.0674407 > >>>>> 25 16 139 123 19.6768 0 - 0.0674407 > >>>>> 26 16 139 123 18.92 0 - 0.0674407 > >>>>> 27 16 139 123 18.2192 0 - 0.0674407 > >>>>> 28 16 139 123 17.5686 0 - 0.0674407 > >>>>> 29 16 139 123 16.9628 0 - 0.0674407 > >>>>> 30 16 139 123 16.3973 0 - 0.0674407 > >>>>> 31 16 139 123 15.8684 0 - 0.0674407 > >>>>> 32 16 139 123 15.3725 0 - 0.0674407 > >>>>> 33 16 139 123 14.9067 0 - 0.0674407 > >>>>> 34 16 139 123 14.4683 0 - 0.0674407 > >>>>> 35 16 139 123 14.0549 0 - 0.0674407 > >>>>> 36 16 139 123 13.6645 0 - 0.0674407 > >>>>> 37 16 139 123 13.2952 0 - 0.0674407 > >>>>> 38 16 139 123 12.9453 0 - 0.0674407 > >>>>> 39 16 139 123 12.6134 0 - 0.0674407 > >>>>> 2015-09-07 15:55:12.697124min lat: 0.022076 max lat: 0.46117 avg lat: > 0.0674407 > >>>>> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat > >>>>> 40 16 139 123 12.2981 0 - 0.0674407 > >>>>> 41 16 139 123 11.9981 0 - 0.0674407 > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> cluster 86edf8b8-b353-49f1-ab0a-a4827a9ea5e8 > >>>>> health HEALTH_WARN > >>>>> 1 requests are blocked > 32 sec > >>>>> monmap e3: 3 mons at > >>>>> {stor0111=10.100.1.111:6789/0,stor0113=10.100.1.113:6789/0,stor011 > >>>>> 5=10.100.1.115:6789/0} > >>>>> election epoch 32, quorum 0,1,2 stor0111,stor0113,stor0115 > >>>>> osdmap e19536: 50 osds: 50 up, 50 in > >>>>> pgmap v928610: 2752 pgs, 9 pools, 30476 GB data, 4183 kobjects > >>>>> 91513 GB used, 47642 GB / 135 TB avail > >>>>> 2752 active+clean > >>>>> > >>>>> > >>>>> Tried using RBD > >>>>> > >>>>> > >>>>> # dd if=/dev/zero of=file1 bs=4K count=10000 oflag=direct > >>>>> 10000+0 records in > >>>>> 10000+0 records out > >>>>> 40960000 bytes (41 MB) copied, 24.5529 s, 1.7 MB/s > >>>>> > >>>>> # dd if=/dev/zero of=file1 bs=1M count=100 oflag=direct > >>>>> 100+0 records in > >>>>> 100+0 records out > >>>>> 104857600 bytes (105 MB) copied, 1.05602 s, 9.3 MB/s > >>>>> > >>>>> # dd if=/dev/zero of=file1 bs=1G count=1 oflag=direct > >>>>> 1+0 records in > >>>>> 1+0 records out > >>>>> 1073741824 bytes (1.1 GB) copied, 293.551 s, 3.7 MB/s ]# > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> _______________________________________________ > >>>>> ceph-users mailing list > >>>>> > >>>>> ceph-users@lists.ceph.com > >>>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> ceph-users mailing list > >>>> ceph-users@lists.ceph.com > >>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >>> > >>> _______________________________________________ > >>> ceph-users mailing list > >>> ceph-users@lists.ceph.com > >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > >> > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
