Hi Christian,

Good day to you, and thank you for your reply.

On Wed, Apr 23, 2014 at 11:41 PM, Christian Balzer <[email protected]> wrote:

> > > > Using 32 concurrent writes, result is below. The speed really
> > > > fluctuates.
> > > >
> > > >  Total time run:         64.31704964.317049
> > > > Total writes made:      1095
> > > > Write size:             4194304
> > > > Bandwidth (MB/sec):     68.100
> > > >
> > > > Stddev Bandwidth:       44.6773
> > > > Max bandwidth (MB/sec): 184
> > > > Min bandwidth (MB/sec): 0
> > > > Average Latency:        1.87761
> > > > Stddev Latency:         1.90906
> > > > Max latency:            9.99347
> > > > Min latency:            0.075849
> > > >
> > > That is really weird, it should get faster, not slower. ^o^
> > > I assume you've run this a number of times?
> > >
> > > Also my apologies, the default is 16 threads, not 1, but that still
> > > isn't enough to get my cluster to full speed:
> > > ---
> > > Bandwidth (MB/sec):     349.044
> > >
> > > Stddev Bandwidth:       107.582
> > > Max bandwidth (MB/sec): 408
> > > ---
> > > at 64 threads it will ramp up from a slow start to:
> > > ---
> > > Bandwidth (MB/sec):     406.967
> > >
> > > Stddev Bandwidth:       114.015
> > > Max bandwidth (MB/sec): 452
> > > ---
> > >
> > > But what stands out is your latency. I don't have a 10GBE network to
> > > compare, but my Infiniband based cluster (going through at least one
> > > switch) gives me values like this:
> > > ---
> > > Average Latency:        0.335519
> > > Stddev Latency:         0.177663
> > > Max latency:            1.37517
> > > Min latency:            0.1017
> > > ---
> > >
> > > Of course that latency is not just the network.
> > >
> >
> > What else can contribute to this latency? Storage node load, disk speed,
> > anything else?
> >
> That and the network itself are pretty much it, you should know once
> you've run those test with atop or iostat on the storage nodes.
>
> >
> > > I would suggest running atop (gives you more information at one
> > > glance) or "iostat -x 3" on all your storage nodes during these tests
> > > to identify any node or OSD that is overloaded in some way.
> > >
> >
> > Will try.
> >
> Do that and let us know about the results.
>

I have done some tests using iostat and noted some OSDs on a particular
storage node going up to the 100% limit when I run the rados bench test.

====
avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.09    0.00    0.92   21.74    0.00   76.25

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.00    4.33   42.00    73.33  6980.00
304.46     0.29    6.22    0.00    6.86   1.50   6.93
sdb               0.00     0.00    0.00   17.67     0.00  6344.00
718.19    59.64  854.26    0.00  854.26  56.60 *100.00*
sdc               0.00     0.00   12.33   59.33    70.67 18882.33
528.92    36.54  509.80   64.76  602.31  10.51  75.33
sdd               0.00     0.00    3.33   54.33    24.00 15249.17
529.71     1.29   22.45    3.20   23.63   1.64   9.47
sde               0.00     0.33    0.00    0.67     0.00     4.00
12.00     0.30  450.00    0.00  450.00 450.00  30.00

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.38    0.00    1.13    7.75    0.00   89.74

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.00    5.00   69.00    30.67 19408.50
525.38     4.29   58.02    0.53   62.18   2.00  14.80
sdb               0.00     0.00    7.00   63.33    41.33 20911.50
595.82    13.09  826.96   88.57  908.57   5.48  38.53
sdc               0.00     0.00    2.67   30.00    17.33  6945.33
426.29     0.21    6.53    0.50    7.07   1.59   5.20
sdd               0.00     0.00    2.67   58.67    16.00 20661.33
674.26     4.89   79.54   41.00   81.30   2.70  16.53
sde               0.00     0.00    0.00    1.67     0.00     6.67
8.00     0.01    3.20    0.00    3.20   1.60   0.27

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.97    0.00    0.55    6.73    0.00   91.75

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.00    1.67   15.33    21.33   120.00
16.63     0.02    1.18    0.00    1.30   0.63   1.07
sdb               0.00     0.00    4.33   62.33    24.00 13299.17
399.69     2.68   11.18    1.23   11.87   1.94  12.93
sdc               0.00     0.00    0.67   38.33    70.67  7881.33
407.79    37.66  202.15    0.00  205.67  13.61  53.07
sdd               0.00     0.00    3.00   17.33    12.00   166.00
17.51     0.05    2.89    3.11    2.85   0.98   2.00
sde               0.00     0.00    0.00    0.00     0.00     0.00
0.00     0.00    0.00    0.00    0.00   0.00   0.00

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.29    0.00    0.92   24.10    0.00   73.68

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.00    0.00   45.33     0.00  4392.50
193.79     0.62   13.62    0.00   13.62   1.09   4.93
sdb               0.00     0.00    0.00    8.67     0.00  3600.00
830.77    63.87 1605.54    0.00 1605.54 115.38 *100.00*
sdc               0.00     0.33    8.67   42.67    37.33  5672.33
222.45    16.88  908.78    1.38 1093.09   7.06  36.27
sdd               0.00     0.00    0.33   31.00     1.33   629.83
40.29     0.06    1.91    0.00    1.94   0.94   2.93
sde               0.00     0.00    0.00    0.33     0.00     1.33
8.00     0.12  368.00    0.00  368.00 368.00  12.27

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           1.59    0.00    0.88    4.82    0.00   92.70

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz
avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.00    0.00   29.00     0.00   235.00
16.21     0.06    1.98    0.00    1.98   0.97   2.80
sdb               0.00     6.00    4.33  114.67    38.67  6422.33
108.59     9.19  513.19  265.23  522.56   2.08  24.80
sdc               0.00     0.00    0.00   20.67     0.00   124.00
12.00     0.04    2.00    0.00    2.00   1.03   2.13
sdd               0.00     5.00    1.67   81.00    12.00   546.17
13.50     0.10    1.21    0.80    1.22   0.39   3.20
sde               0.00     0.00    0.00    0.00     0.00     0.00
0.00     0.00    0.00    0.00    0.00   0.00   0.00
====

And the high utilisation is randomly affecting other OSDs as well within
the same node, and not only affecting one particular OSD.

atop result on the node:

====
ATOP -
ceph-osd-07
2014/04/24
13:49:12
------                                                              10s
elapsed
PRC | sys    1.77s |  user   2.11s |              |               |
#proc    164 |               | #trun      2 | #tslpi  2817  | #tslpu     0
|               | #zombie    0 | clones     4  |
|               | #exit      0 |
CPU | sys      14% |  user     20% |              |  irq       1%
|              |               | idle    632% | wait    133%
|              |               | steal     0% | guest     0%
|              | avgf 1.79GHz  | avgscal  54% |
cpu | sys       6% |  user      7% |              |  irq       0%
|              |               | idle     19% | cpu006 w 68%
|              |               | steal     0% | guest     0%
|              | avgf 2.42GHz  | avgscal  73% |
cpu | sys       2% |  user      3% |              |  irq       0%
|              |               | idle     88% | cpu002 w  7%
|              |               | steal     0% | guest     0%
|              | avgf 1.68GHz  | avgscal  50% |
cpu | sys       2% |  user      2% |              |  irq       0%
|              |               | idle     86% | cpu003 w 10%
|              |               | steal     0% | guest     0%
|              | avgf 1.67GHz  | avgscal  50% |
cpu | sys       2% |  user      2% |              |  irq       0%
|              |               | idle     75% | cpu001 w 21%
|              |               | steal     0% | guest     0%
|              | avgf 1.83GHz  | avgscal  55% |
cpu | sys       1% |  user      2% |              |  irq       1%
|              |               | idle     70% | cpu000 w 26%
|              |               | steal     0% | guest     0%
|              | avgf 1.85GHz  | avgscal  56% |
cpu | sys       1% |  user      2% |              |  irq       0%
|              |               | idle     97% | cpu004 w  1%
|              |               | steal     0% | guest     0%
|              | avgf 1.64GHz  | avgscal  49% |
cpu | sys       1% |  user      1% |              |  irq       0%
|              |               | idle     98% | cpu005 w  0%
|              |               | steal     0% | guest     0%
|              | avgf 1.60GHz  | avgscal  48% |
cpu | sys       0% |  user      1% |              |  irq       0%
|              |               | idle     98% | cpu007 w  0%
|              |               | steal     0% | guest     0%
|              | avgf 1.60GHz  | avgscal  48% |
CPL | avg1    1.12 |               | avg5    0.90 |               | avg15
0.72 |               |              |               | csw   103682
|               | intr   34330 |               |
|               | numcpu     8 |
MEM | tot    15.6G |               | free  158.2M |  cache  13.7G
|              |  dirty 101.4M | buff   18.2M |               | slab
574.6M |               |              |               |
|               |              |
SWP | tot   518.0M |               | free  489.6M |
|              |               |              |
|              |               |              |               | vmcom
5.2G |               | vmlim   8.3G |
PAG | scan  327450 |               |              |  stall      0
|              |               |              |
|              |               | swin       0 |
|              |               | swout      0 |
DSK |          sdb |               | busy     90% |  read    8115
|              |  write    695 | KiB/r    130 |               | KiB/w
194 | MBr/s 103.34  |              | MBw/s  13.22  | avq     4.61
|               | avio 1.01 ms |
DSK |          sdc |               | busy     32% |  read      23
|              |  write    431 | KiB/r      6 |               | KiB/w
318 | MBr/s   0.02  |              | MBw/s  13.41  | avq    34.86
|               | avio 6.95 ms |
DSK |          sda |               | busy     32% |  read      25
|              |  write    674 | KiB/r      6 |               | KiB/w
193 | MBr/s   0.02  |              | MBw/s  12.76  | avq    41.00
|               | avio 4.48 ms |
DSK |          sdd |               | busy      7% |  read      26
|              |  write    473 | KiB/r      7 |               | KiB/w
223 | MBr/s   0.02  |              | MBw/s  10.31  | avq    14.29
|               | avio 1.45 ms |
DSK |          sde |               | busy      2% |  read       0
|              |  write      5 | KiB/r      0 |               | KiB/w
5 | MBr/s   0.00  |              | MBw/s   0.00  | avq     1.00
|               | avio 44.8 ms |
NET | transport    |  tcpi   21326 |              |  tcpo   27479 |
udpi       0 |  udpo       0 | tcpao      0 |               | tcppo      2
| tcprs      3  | tcpie      0 | tcpor      0  |              | udpnp
0  | udpip      0 |
NET | network      |               | ipi    21326 |  ipo    14340
|              |  ipfrw      0 | deliv  21326 |
|              |               |              |               | icmpi
0 |               | icmpo      0 |
NET | p2p2    ---- |  pcki   12659 |              |  pcko   20931 | si  124
Mbps |               | so  107 Mbps | coll       0  | mlti       0
|               | erri       0 | erro       0  |              | drpi
0  | drpo       0 |
NET | p2p1    ---- |  pcki    8565 |              |  pcko    6443 | si  106
Mbps |               | so 7911 Kbps | coll       0  | mlti       0
|               | erri       0 | erro       0  |              | drpi
0  | drpo       0 |
NET | lo      ---- |  pcki     108 |              |  pcko     108 | si    8
Kbps |               | so    8 Kbps | coll       0  | mlti       0
|               | erri       0 | erro       0  |              | drpi
0  | drpo       0 |

  PID         RUID              EUID              THR
SYSCPU           USRCPU          VGROW           RGROW
RDDSK          WRDSK          ST          EXC         S
CPUNR           CPU         CMD         1/1
 6881         root              root              538
0.74s            0.94s             0K            256K
1.0G         121.3M          --            -         S
3           17%         ceph-osd
28708         root              root              720
0.30s            0.69s           512K             -8K
160K         157.7M          --            -         S
3           10%         ceph-osd
31569         root              root              678
0.21s            0.30s           512K           -584K
156K         162.7M          --            -         S
0            5%         ceph-osd
32095         root              root              654
0.14s            0.16s             0K              0K
60K         105.9M          --            -         S
0            3%         ceph-osd
   61         root              root                1
0.20s            0.00s             0K              0K
0K             0K          --            -         S
3            2%         kswapd0
10584         root              root                1
0.03s            0.02s           112K            112K
0K             0K          --            -         R
4            1%         atop
11618         root              root                1
0.03s            0.00s             0K              0K
0K             0K          --            -         S
6            0%         kworker/6:2
   10         root              root                1
0.02s            0.00s             0K              0K
0K             0K          --            -         S
0            0%         rcu_sched
   38         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
6            0%         ksoftirqd/6
 1623         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
6            0%         kworker/6:1H
 1993         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
2            0%         flush-8:48
 2031         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
2            0%         flush-8:0
 2032         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
0            0%         flush-8:16
 2033         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
2            0%         flush-8:32
 5787         root              root                1
0.01s            0.00s             0K              0K
4K             0K          --            -         S
3            0%         kworker/3:0
27605         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
1            0%         kworker/1:2
27823         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
0            0%         kworker/0:2
32511         root              root                1
0.01s            0.00s             0K              0K
0K             0K          --            -         S
2            0%         kworker/2:0
 1536         root              root                1
0.00s            0.00s             0K              0K
0K             0K          --            -         S
2            0%         irqbalance
  478         root              root                1
0.00s            0.00s             0K              0K
0K             0K          --            -         S
3            0%         usb-storage
  494         root              root                1
0.00s            0.00s             0K              0K
0K             0K          --            -         S
1            0%         jbd2/sde1-8
 1550         root              root                1
0.00s            0.00s             0K              0K
400K             0K          --            -         S
1            0%         xfsaild/sdb1
 1750         root              root                1
0.00s            0.00s             0K              0K
128K             0K          --            -         S
2            0%         xfsaild/sdd1
 1994         root              root                1
0.00s            0.00s             0K              0K
0K             0K          --            -         S
1            0%         flush-8:64
====

I have tried to trim the SSD drives but the problem seems to persist. Last
time trimming the SSD drives can help to improve the performance.

Any advice is greatly appreciated.

Thank you.
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