From: Mark Nelson <mark.nelson@inktank.com>
To: Stefan Priebe <s.priebe@profihost.ag>
Cc: "ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>
Subject: Re: Heavy speed difference between rbd and custom pool
Date: Mon, 18 Jun 2012 17:23:49 -0500 [thread overview]
Message-ID: <4FDFAA75.5070309@inktank.com> (raw)
In-Reply-To: <4FDFA01A.2010107@profihost.ag>
On 06/18/2012 04:39 PM, Stefan Priebe wrote:
> Hello list,
>
> i'm getting these rbd bench values for pool rbd. They're high and constant.
> ----------------------------- RBD pool
> # rados -p rbd bench 30 write -t 16
> Maintaining 16 concurrent writes of 4194304 bytes for at least 30 seconds.
> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat
> 0 0 0 0 0 0 - 0
> 1 16 274 258 1031.77 1032 0.043758 0.0602236
> 2 16 549 533 1065.82 1100 0.072168 0.0590944
> 3 16 825 809 1078.5 1104 0.040162 0.058682
> 4 16 1103 1087 1086.84 1112 0.052508 0.0584277
> 5 16 1385 1369 1095.04 1128 0.060233 0.0581288
> 6 16 1654 1638 1091.85 1076 0.050697 0.0583385
> 7 16 1939 1923 1098.71 1140 0.063716 0.057964
> 8 16 2219 2203 1101.35 1120 0.055435 0.0579105
> 9 16 2497 2481 1102.52 1112 0.060413 0.0578282
> 10 16 2773 2757 1102.66 1104 0.051134 0.0578561
> 11 16 3049 3033 1102.77 1104 0.057742 0.0578803
> 12 16 3326 3310 1103.19 1108 0.053769 0.0578627
> 13 16 3604 3588 1103.86 1112 0.064574 0.0578453
> 14 16 3883 3867 1104.72 1116 0.056524 0.0578018
> 15 16 4162 4146 1105.46 1116 0.054581 0.0577626
> 16 16 4440 4424 1105.86 1112 0.079015 0.057758
> 17 16 4725 4709 1107.86 1140 0.043511 0.0576647
> 18 16 5007 4991 1108.97 1128 0.053005 0.0576147
> 19 16 5292 5276 1110.6 1140 0.069004 0.057538
> 2012-06-18 23:36:19.124472min lat: 0.028568 max lat: 0.201941 avg lat:
> 0.0574953
> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat
> 20 16 5574 5558 1111.46 1128 0.048482 0.0574953
> 21 16 5861 5845 1113.18 1148 0.051923 0.0574146
> 22 16 6147 6131 1114.58 1144 0.04461 0.0573461
> 23 16 6438 6422 1116.72 1164 0.050383 0.0572406
> 24 16 6724 6708 1117.85 1144 0.067827 0.0571864
> 25 16 7008 6992 1118.57 1136 0.049128 0.057147
> 26 16 7296 7280 1119.85 1152 0.050331 0.0570879
> 27 16 7573 7557 1119.4 1108 0.052711 0.0571132
> 28 16 7858 7842 1120.13 1140 0.056369 0.0570764
> 29 16 8143 8127 1120.81 1140 0.046558 0.0570438
> 30 16 8431 8415 1121.85 1152 0.049958 0.0569942
> Total time run: 30.045481
> Total writes made: 8431
> Write size: 4194304
> Bandwidth (MB/sec): 1122.432
>
> Stddev Bandwidth: 26.0451
> Max bandwidth (MB/sec): 1164
> Min bandwidth (MB/sec): 1032
> Average Latency: 0.0570069
> Stddev Latency: 0.0128039
> Max latency: 0.235536
> Min latency: 0.028568
> -----------------------------
>
> I created then a custom pool called kvmpool.
>
> ~# ceph osd pool create kvmpool
> pool 'kvmpool' created
>
> But with this one i get slow and jumping values:
> -------------------------------- kvmpool
> ~# rados -p kvmpool bench 30 write -t 16
> Maintaining 16 concurrent writes of 4194304 bytes for at least 30 seconds.
> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat
> 0 0 0 0 0 0 - 0
> 1 16 231 215 859.863 860 0.204867 0.069195
> 2 16 393 377 753.899 648 0.049444 0.0811933
> 3 16 535 519 691.908 568 0.232365 0.0899074
> 4 16 634 618 617.913 396 0.032758 0.0963399
> 5 16 806 790 631.913 688 0.075811 0.099529
> 6 16 948 932 621.249 568 0.156988 0.10179
> 7 16 1086 1070 611.348 552 0.036177 0.102064
> 8 16 1206 1190 594.922 480 0.028491 0.105235
> 9 16 1336 1320 586.589 520 0.041009 0.108735
> 10 16 1512 1496 598.32 704 0.258165 0.105086
> 11 16 1666 1650 599.921 616 0.040967 0.106146
> 12 15 1825 1810 603.255 640 0.198851 0.105463
> 13 16 1925 1909 587.309 396 0.042577 0.108449
> 14 16 2135 2119 605.352 840 0.035767 0.105219
> 15 16 2272 2256 601.523 548 0.246136 0.105357
> 16 16 2426 2410 602.424 616 0.19881 0.105692
> 17 16 2529 2513 591.22 412 0.031322 0.105463
> 18 16 2696 2680 595.48 668 0.028081 0.106749
> 19 16 2878 2862 602.449 728 0.044929 0.105856
> 2012-06-18 23:38:45.566094min lat: 0.023295 max lat: 0.763797 avg lat:
> 0.105597
> sec Cur ops started finished avg MB/s cur MB/s last lat avg lat
> 20 16 3041 3025 604.921 652 0.036028 0.105597
> 21 16 3182 3166 602.964 564 0.035072 0.104915
> 22 16 3349 3333 605.916 668 0.030493 0.105304
> 23 16 3512 3496 607.917 652 0.030523 0.10479
> 24 16 3668 3652 608.584 624 0.232933 0.10475
> 25 16 3821 3805 608.717 612 0.029881 0.104513
> 26 16 3963 3947 607.148 568 0.050244 0.10531
> 27 16 4112 4096 606.733 596 0.259069 0.105008
> 28 16 4261 4245 606.347 596 0.211877 0.105215
> 29 16 4437 4421 609.712 704 0.02802 0.104613
> 30 16 4566 4550 606.586 516 0.047076 0.105111
> Total time run: 30.062141
> Total writes made: 4566
> Write size: 4194304
> Bandwidth (MB/sec): 607.542
>
> Stddev Bandwidth: 109.112
> Max bandwidth (MB/sec): 860
> Min bandwidth (MB/sec): 396
> Average Latency: 0.10532
> Stddev Latency: 0.108369
> Max latency: 0.763797
> Min latency: 0.023295
> --------------------------------
>
> Why do these pools differ? Where is the difference?
>
> Stefan
Are the number of placement groups the same for each pool?
try running "ceph osd dump -o - | grep <pool>" and looking for the
pg_num value.
Mark
next prev parent reply other threads:[~2012-06-18 22:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-18 21:39 Heavy speed difference between rbd and custom pool Stefan Priebe
2012-06-18 22:23 ` Mark Nelson [this message]
2012-06-18 22:41 ` Dan Mick
2012-06-19 6:06 ` Stefan Priebe
2012-06-19 6:30 ` Stefan Priebe - Profihost AG
2012-06-19 4:41 ` Alexandre DERUMIER
2012-06-19 6:32 ` Stefan Priebe - Profihost AG
2012-06-19 13:01 ` Mark Nelson
2012-06-19 13:14 ` Stefan Priebe - Profihost AG
2012-06-19 14:05 ` bad performance fio random write - rados bench random write to compare? Alexandre DERUMIER
2012-07-02 19:52 ` Gregory Farnum
2012-07-03 7:31 ` Stefan Priebe - Profihost AG
2012-06-19 15:42 ` Heavy speed difference between rbd and custom pool Sage Weil
2012-06-19 16:24 ` Stefan Priebe
2012-06-19 16:27 ` Sage Weil
2012-06-19 16:29 ` Dan Mick
2012-06-20 6:46 ` Stefan Priebe - Profihost AG
2012-06-20 23:21 ` Dan Mick
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