Thread: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Laurent Laborde
Date:
2 kingston V+100 500GB
Soft RAID1 (md)
ioscheduler [noop]
ext3
Linux pro-cdn1 2.6.26-2-amd64 #1 SMP Tue Jan 25 05:59:43 UTC 2011
x86_64 GNU/Linux
Filesystem            Size  Used Avail Use% Mounted on
/dev/md4              452G  301G  128G  71% /home/ssd
--------

Random 8KB read/write with 1% write
./pgiosim  -w1 -a1 -v -b 1000000 /home/ssd/big.1
Write Mode: 1%
Stallcheck at 1.000000
Verbose
Unknown units of blocks
Arg: 1
Read 1000000 blocks
Added /home/ssd/big.1

-------

3.20%,  32036 read,    300 written, 25625.08kB/sec 3203.14 iops
5.33%,  21283 read,    198 written, 17026.31kB/sec 2128.29 iops
7.47%,  21356 read,    245 written, 17084.73kB/sec 2135.59 iops
9.62%,  21511 read,    234 written, 17208.72kB/sec 2151.09 iops
11.78%,  21591 read,    216 written, 17271.71kB/sec 2158.96 iops
14.08%,  23032 read,    245 written, 18425.52kB/sec 2303.19 iops
16.53%,  24527 read,    228 written, 19621.52kB/sec 2452.69 iops
18.89%,  23535 read,    225 written, 18827.91kB/sec 2353.49 iops
21.19%,  23003 read,    229 written, 18402.34kB/sec 2300.29 iops
23.40%,  22139 read,    211 written, 17711.13kB/sec 2213.89 iops
25.66%,  22628 read,    225 written, 18102.33kB/sec 2262.79 iops
27.86%,  21983 read,    238 written, 17586.32kB/sec 2198.29 iops
30.14%,  22823 read,    211 written, 18258.31kB/sec 2282.29 iops
32.44%,  22975 read,    240 written, 18379.92kB/sec 2297.49 iops
34.83%,  23870 read,    214 written, 19095.92kB/sec 2386.99 iops
37.24%,  24129 read,    213 written, 19303.10kB/sec 2412.89 iops
39.49%,  22450 read,    210 written, 17959.92kB/sec 2244.99 iops
41.77%,  22827 read,    235 written, 18261.53kB/sec 2282.69 iops
43.98%,  22138 read,    218 written, 17710.30kB/sec 2213.79 iops
46.31%,  23293 read,    241 written, 18634.30kB/sec 2329.29 iops
48.86%,  25422 read,    258 written, 20337.52kB/sec 2542.19 iops
51.06%,  22091 read,    222 written, 17672.72kB/sec 2209.09 iops
53.46%,  23970 read,    215 written, 19175.93kB/sec 2396.99 iops
55.80%,  23359 read,    224 written, 18687.12kB/sec 2335.89 iops
58.04%,  22472 read,    232 written, 17977.24kB/sec 2247.16 iops
60.34%,  22981 read,    230 written, 18384.72kB/sec 2298.09 iops
62.17%,  18228 read,    192 written, 14580.33kB/sec 1822.54 iops
64.60%,  24336 read,    229 written, 19465.85kB/sec 2433.23 iops
66.89%,  22912 read,    210 written, 18329.52kB/sec 2291.19 iops
69.06%,  21677 read,    231 written, 17341.54kB/sec 2167.69 iops
71.28%,  22255 read,    210 written, 17803.91kB/sec 2225.49 iops
73.68%,  23928 read,    243 written, 19142.30kB/sec 2392.79 iops
75.90%,  22255 read,    205 written, 17803.93kB/sec 2225.49 iops
78.17%,  22641 read,    233 written, 18112.72kB/sec 2264.09 iops
80.50%,  23328 read,    235 written, 18662.29kB/sec 2332.79 iops
82.84%,  23379 read,    230 written, 18703.11kB/sec 2337.89 iops
84.90%,  20670 read,    236 written, 16535.95kB/sec 2066.99 iops
86.91%,  20018 read,    222 written, 16012.14kB/sec 2001.52 iops
89.24%,  23321 read,    235 written, 18654.39kB/sec 2331.80 iops
91.56%,  23224 read,    227 written, 18579.13kB/sec 2322.39 iops
94.05%,  24880 read,    262 written, 19903.93kB/sec 2487.99 iops
96.40%,  23549 read,    205 written, 18839.14kB/sec 2354.89 iops
98.80%,  23956 read,    230 written, 19164.73kB/sec 2395.59 iops

------
./pgiosim  -w10 -a1 -v -b 1000000 /home/ssd/big.1
Write Mode: 10%
Stallcheck at 1.000000
Verbose
Unknown units of blocks
Arg: 1
Read 1000000 blocks
Added /home/ssd/big.1

1.62%,  16226 read,   1642 written, 12979.00kB/sec 1622.37 iops
1.67%,    433 read,     38 written,  346.40kB/sec   43.30 iops
2.95%,  12839 read,   1282 written, 10271.06kB/sec 1283.88 iops
2.95%,      3 read,      0 written,    2.40kB/sec    0.30 iops
3.50%,   5500 read,    548 written, 4399.83kB/sec  549.98 iops
4.95%,  14524 read,   1468 written, 11619.12kB/sec 1452.39 iops
4.95%,      3 read,      1 written,    2.40kB/sec    0.30 iops
4.95%,      8 read,      0 written,    6.40kB/sec    0.80 iops
6.20%,  12471 read,   1241 written, 9976.67kB/sec 1247.08 iops
6.20%,      3 read,      0 written,    2.40kB/sec    0.30 iops
7.63%,  14272 read,   1445 written, 11417.26kB/sec 1427.16 iops
7.63%,      3 read,      0 written,    2.40kB/sec    0.30 iops
7.65%,    263 read,     22 written,  210.40kB/sec   26.30 iops
8.65%,   9930 read,    990 written, 7943.83kB/sec  992.98 iops
8.67%,    268 read,     24 written,  214.40kB/sec   26.80 iops
9.30%,   6296 read,    621 written, 5036.78kB/sec  629.60 iops
9.83%,   5233 read,    541 written, 4186.35kB/sec  523.29 iops
10.75%,   9222 read,    960 written, 7377.56kB/sec  922.20 iops
10.80%,    506 read,     52 written,  404.80kB/sec   50.60 iops
11.74%,   9417 read,    933 written, 7533.53kB/sec  941.69 iops
11.77%,    314 read,     29 written,  251.20kB/sec   31.40 iops
12.56%,   7906 read,    793 written, 6324.78kB/sec  790.60 iops
13.37%,   8052 read,    830 written, 6441.52kB/sec  805.19 iops
13.40%,    309 read,     29 written,  247.20kB/sec   30.90 iops
14.01%,   6116 read,    635 written, 4892.73kB/sec  611.59 iops
14.71%,   6994 read,    675 written, 5595.18kB/sec  699.40 iops
15.83%,  11205 read,   1188 written, 8953.19kB/sec 1119.15 iops
15.90%,    651 read,     68 written,  520.80kB/sec   65.10 iops
16.33%,   4355 read,    490 written, 3480.77kB/sec  435.10 iops
17.14%,   8098 read,    777 written, 6478.33kB/sec  809.79 iops
17.14%,      6 read,      0 written,    4.80kB/sec    0.60 iops
18.70%,  15603 read,   1622 written, 12482.33kB/sec 1560.29 iops
18.70%,      4 read,      0 written,    3.20kB/sec    0.40 iops
18.71%,     34 read,      5 written,   27.20kB/sec    3.40 iops
19.29%,   5829 read,    595 written, 4663.08kB/sec  582.89 iops
20.81%,  15209 read,   1477 written, 12167.16kB/sec 1520.90 iops
20.81%,      3 read,      0 written,    2.40kB/sec    0.30 iops
20.82%,     61 read,      8 written,   48.80kB/sec    6.10 iops
21.98%,  11665 read,   1144 written, 9331.42kB/sec 1166.43 iops
21.98%,      2 read,      0 written,    1.60kB/sec    0.20 iops
22.78%,   7988 read,    817 written, 6389.86kB/sec  798.73 iops
23.12%,   3364 read,    346 written, 2690.97kB/sec  336.37 iops
23.49%,   3746 read,    357 written, 2996.69kB/sec  374.59 iops
24.67%,  11720 read,   1137 written, 9375.97kB/sec 1172.00 iops
24.67%,      4 read,      0 written,    3.20kB/sec    0.40 iops
25.50%,   8365 read,    808 written, 6691.96kB/sec  836.49 iops
25.69%,   1865 read,    190 written, 1491.33kB/sec  186.42 iops
26.14%,   4462 read,    424 written, 3569.58kB/sec  446.20 iops
27.07%,   9377 read,    928 written, 7494.42kB/sec  936.80 iops
27.58%,   5103 read,    532 written, 4082.37kB/sec  510.30 iops
28.54%,   9537 read,    918 written, 7619.92kB/sec  952.49 iops
28.70%,   1600 read,    151 written, 1279.99kB/sec  160.00 iops
29.99%,  12901 read,   1247 written, 10307.61kB/sec 1288.45 iops
30.12%,   1339 read,    139 written, 1071.19kB/sec  133.90 iops
30.16%,    421 read,     41 written,  336.75kB/sec   42.09 iops
30.60%,   4368 read,    486 written, 3494.38kB/sec  436.80 iops
32.16%,  15580 read,   1585 written, 12463.80kB/sec 1557.97 iops
32.16%,      2 read,      0 written,    1.60kB/sec    0.20 iops
32.19%,    330 read,     21 written,  263.97kB/sec   33.00 iops
32.92%,   7302 read,    748 written, 5841.50kB/sec  730.19 iops
33.95%,  10339 read,   1030 written, 8269.88kB/sec 1033.74 iops
33.96%,      4 read,      0 written,    3.20kB/sec    0.40 iops
34.32%,   3673 read,    374 written, 2938.35kB/sec  367.29 iops
35.66%,  13395 read,   1335 written, 10715.92kB/sec 1339.49 iops
35.66%,      9 read,      3 written,    7.20kB/sec    0.90 iops
36.05%,   3890 read,    389 written, 3111.96kB/sec  388.99 iops
37.19%,  11383 read,   1104 written, 9097.74kB/sec 1137.22 iops
37.19%,      2 read,      0 written,    1.60kB/sec    0.20 iops
38.62%,  14295 read,   1511 written, 11421.06kB/sec 1427.63 iops
38.62%,      6 read,      0 written,    4.80kB/sec    0.60 iops
38.62%,      2 read,      0 written,    1.60kB/sec    0.20 iops
39.20%,   5831 read,    579 written, 4664.78kB/sec  583.10 iops
40.25%,  10453 read,   1006 written, 8355.83kB/sec 1044.48 iops
40.25%,      2 read,      0 written,    1.60kB/sec    0.20 iops
41.72%,  14710 read,   1501 written, 11767.59kB/sec 1470.95 iops
41.72%,      4 read,      0 written,    3.20kB/sec    0.40 iops
41.72%,      2 read,      0 written,    1.60kB/sec    0.20 iops
42.87%,  11472 read,   1144 written, 9177.50kB/sec 1147.19 iops
42.87%,      5 read,      0 written,    4.00kB/sec    0.50 iops
44.08%,  12076 read,   1233 written, 9660.75kB/sec 1207.59 iops
44.08%,      4 read,      1 written,    3.20kB/sec    0.40 iops
44.45%,   3684 read,    364 written, 2947.17kB/sec  368.40 iops
45.71%,  12684 read,   1339 written, 10147.10kB/sec 1268.39 iops
45.71%,      4 read,      0 written,    3.20kB/sec    0.40 iops
46.00%,   2823 read,    284 written, 2256.73kB/sec  282.09 iops
46.41%,   4116 read,    423 written, 3292.78kB/sec  411.60 iops
47.54%,  11360 read,   1121 written, 9087.86kB/sec 1135.98 iops
47.59%,    451 read,     52 written,  360.75kB/sec   45.09 iops
48.25%,   6646 read,    680 written, 5316.07kB/sec  664.51 iops
49.53%,  12717 read,   1281 written, 10173.34kB/sec 1271.67 iops
49.53%,      4 read,      0 written,    3.20kB/sec    0.40 iops
49.84%,   3107 read,    311 written, 2484.65kB/sec  310.58 iops
50.81%,   9737 read,    961 written, 7789.56kB/sec  973.69 iops
50.81%,      4 read,      1 written,    3.20kB/sec    0.40 iops
51.69%,   8811 read,    934 written, 7047.89kB/sec  880.99 iops
51.82%,   1281 read,    129 written, 1024.53kB/sec  128.07 iops
52.89%,  10674 read,   1034 written, 8539.07kB/sec 1067.38 iops
52.89%,     14 read,      3 written,   11.20kB/sec    1.40 iops
53.41%,   5235 read,    532 written, 4187.99kB/sec  523.50 iops
54.08%,   6711 read,    679 written, 5368.75kB/sec  671.09 iops
54.94%,   8535 read,    878 written, 6827.91kB/sec  853.49 iops
54.94%,      4 read,      0 written,    3.20kB/sec    0.40 iops
55.65%,   7086 read,    682 written, 5668.57kB/sec  708.57 iops
57.23%,  15799 read,   1561 written, 12639.04kB/sec 1579.88 iops
57.23%,      2 read,      0 written,    1.60kB/sec    0.20 iops
57.23%,      4 read,      0 written,    3.20kB/sec    0.40 iops
57.83%,   6043 read,    615 written, 4833.90kB/sec  604.24 iops
59.43%,  16034 read,   1657 written, 12827.16kB/sec 1603.39 iops
59.43%,      5 read,      0 written,    4.00kB/sec    0.50 iops
59.44%,      8 read,      1 written,    6.40kB/sec    0.80 iops
60.81%,  13705 read,   1397 written, 10963.65kB/sec 1370.46 iops
60.81%,      4 read,      0 written,    3.20kB/sec    0.40 iops
60.84%,    377 read,     30 written,  301.55kB/sec   37.69 iops
61.58%,   7402 read,    760 written, 5921.57kB/sec  740.20 iops
62.26%,   6764 read,    679 written, 5411.12kB/sec  676.39 iops
63.18%,   9188 read,    870 written, 7346.94kB/sec  918.37 iops
63.77%,   5951 read,    554 written, 4760.63kB/sec  595.08 iops
63.77%,      5 read,      0 written,    4.00kB/sec    0.50 iops
64.71%,   9386 read,    973 written, 7508.68kB/sec  938.59 iops
64.71%,      4 read,      0 written,    3.20kB/sec    0.40 iops
65.87%,  11559 read,   1142 written, 9246.80kB/sec 1155.85 iops
65.91%,    406 read,     41 written,  324.79kB/sec   40.60 iops
67.53%,  16184 read,   1634 written, 12929.73kB/sec 1616.22 iops
67.53%,      3 read,      0 written,    2.40kB/sec    0.30 iops
67.53%,      3 read,      0 written,    2.40kB/sec    0.30 iops
68.66%,  11289 read,   1124 written, 9031.13kB/sec 1128.89 iops
68.66%,      3 read,      0 written,    2.40kB/sec    0.30 iops
70.12%,  14665 read,   1482 written, 11731.93kB/sec 1466.49 iops
70.13%,      6 read,      1 written,    4.80kB/sec    0.60 iops
70.17%,    489 read,     53 written,  391.20kB/sec   48.90 iops
70.61%,   4311 read,    438 written, 3448.77kB/sec  431.10 iops
72.32%,  17185 read,   1741 written, 13747.94kB/sec 1718.49 iops
72.32%,      4 read,      0 written,    3.20kB/sec    0.40 iops
72.32%,      1 read,      0 written,    0.80kB/sec    0.10 iops
72.97%,   6433 read,    653 written, 5141.42kB/sec  642.68 iops
73.55%,   5830 read,    584 written, 4663.93kB/sec  582.99 iops
74.72%,  11705 read,   1188 written, 9355.64kB/sec 1169.45 iops
74.72%,      1 read,      0 written,    0.80kB/sec    0.10 iops
75.18%,   4561 read,    388 written, 3643.86kB/sec  455.48 iops
75.50%,   3230 read,    292 written, 2583.90kB/sec  322.99 iops
76.88%,  13816 read,   1427 written, 11052.76kB/sec 1381.60 iops
76.88%,      3 read,      1 written,    2.40kB/sec    0.30 iops
77.86%,   9736 read,   1007 written, 7788.77kB/sec  973.60 iops
78.00%,   1424 read,    138 written, 1139.19kB/sec  142.40 iops
78.67%,   6737 read,    675 written, 5389.53kB/sec  673.69 iops
79.50%,   8296 read,    816 written, 6636.43kB/sec  829.55 iops
79.50%,      3 read,      0 written,    2.40kB/sec    0.30 iops
80.44%,   9361 read,    924 written, 7488.75kB/sec  936.09 iops
80.44%,      3 read,      0 written,    2.40kB/sec    0.30 iops
81.66%,  12259 read,   1217 written, 9807.12kB/sec 1225.89 iops
81.66%,      3 read,      1 written,    2.40kB/sec    0.30 iops
82.72%,  10554 read,   1106 written, 8441.93kB/sec 1055.24 iops
82.95%,   2329 read,    224 written, 1863.19kB/sec  232.90 iops
82.99%,    408 read,     39 written,  326.40kB/sec   40.80 iops
84.07%,  10723 read,   1090 written, 8578.37kB/sec 1072.30 iops
84.07%,      4 read,      0 written,    3.20kB/sec    0.40 iops
85.10%,  10379 read,   1028 written, 8303.15kB/sec 1037.89 iops
85.12%,    167 read,     14 written,  133.59kB/sec   16.70 iops
86.31%,  11925 read,   1117 written, 9539.95kB/sec 1192.49 iops
86.31%,      4 read,      1 written,    3.20kB/sec    0.40 iops
86.66%,   3452 read,    352 written, 2761.42kB/sec  345.18 iops
87.77%,  11113 read,   1088 written, 8890.26kB/sec 1111.28 iops
87.77%,      3 read,      1 written,    2.40kB/sec    0.30 iops
88.91%,  11434 read,   1081 written, 9147.12kB/sec 1143.39 iops
88.91%,      5 read,      0 written,    4.00kB/sec    0.50 iops
89.75%,   8341 read,    802 written, 6672.71kB/sec  834.09 iops
90.23%,   4835 read,    491 written, 3867.94kB/sec  483.49 iops
91.12%,   8910 read,    941 written, 7127.93kB/sec  890.99 iops
91.12%,      3 read,      0 written,    2.40kB/sec    0.30 iops
91.71%,   5909 read,    567 written, 4726.76kB/sec  590.85 iops
92.15%,   4316 read,    415 written, 3452.78kB/sec  431.60 iops
93.44%,  12960 read,   1299 written, 10367.83kB/sec 1295.98 iops
93.44%,      4 read,      0 written,    3.20kB/sec    0.40 iops
93.73%,   2857 read,    292 written, 2285.59kB/sec  285.70 iops
95.35%,  16170 read,   1658 written, 12935.95kB/sec 1616.99 iops
95.35%,      3 read,      0 written,    2.40kB/sec    0.30 iops
95.35%,      5 read,      0 written,    4.00kB/sec    0.50 iops
96.65%,  13060 read,   1274 written, 10447.89kB/sec 1305.99 iops
96.65%,      5 read,      0 written,    4.00kB/sec    0.50 iops
97.46%,   8065 read,    853 written, 6451.07kB/sec  806.38 iops
97.57%,   1158 read,    120 written,  926.40kB/sec  115.80 iops
98.70%,  11221 read,   1113 written, 8975.70kB/sec 1121.96 iops
98.70%,     42 read,      4 written,   33.60kB/sec    4.20 iops
99.85%,  11480 read,   1170 written, 9180.01kB/sec 1147.50 iops
99.85%,      2 read,      0 written,    1.60kB/sec    0.20 iops


--
Laurent "ker2x" Laborde
Sysadmin & DBA at http://www.over-blog.com/

Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Laurent Laborde
Date:
Sorry, it's not 2x512GB in Raid1 but 4x256GB in raid10

--
Laurent "ker2x" Laborde
Sysadmin & DBA at http://www.over-blog.com/

On 04/19/2011 05:15 AM, Laurent Laborde wrote:
> 2 kingston V+100 500GB
>

Thanks for the performance report.  The V+100 is based on a Toshiba
T6UG1XBG controller, and it doesn't have any durable cache from either a
battery or capacitor.  As such, putting a database on that drive is very
risky.  You can expect the database to be corrupted during an unusual
power outage event.  See http://wiki.postgresql.org/wiki/Reliable_Writes
for more information.

At this point most people considering one of Kingston's drives for a
database would be better off getting an Intel 320 series drive, which is
around the same price but doesn't have this issue.

--
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books


Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Laurent Laborde
Date:
On Tue, Apr 19, 2011 at 2:07 PM, Greg Smith <greg@2ndquadrant.com> wrote:
> On 04/19/2011 05:15 AM, Laurent Laborde wrote:
>>
>> 2 kingston V+100 500GB

4x250GB in Raid10 (see my 2nd post)

> Thanks for the performance report.  The V+100 is based on a Toshiba T6UG1XBG
> controller, and it doesn't have any durable cache from either a battery or
> capacitor.  As such, putting a database on that drive is very risky.  You
> can expect the database to be corrupted during an unusual power outage
> event.  See http://wiki.postgresql.org/wiki/Reliable_Writes for more
> information.
>
> At this point most people considering one of Kingston's drives for a
> database would be better off getting an Intel 320 series drive, which is
> around the same price but doesn't have this issue.

If we use them (unlikely), recovery in case of power outage isn't a
problem, as we will use it on slave database (using Slony-I) that can
be created/destroyed at will.
And, anyway, our slave have fsync=off so the battery won't change
anything in case of power outage :)

i am currently testing on a single V+100 250GB (without raid).
Report will follow soon :)

--
Laurent "ker2x" Laborde
Sysadmin & DBA at http://www.over-blog.com/

Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Laurent Laborde
Date:
1 SSD Kingston V+100 250GB, no raid.

/home/pgiosim-0.5/pgiosim  -w1 -a1 -v -b 1000000 /home/ssd/big1
Write Mode: 1%
Stallcheck at 1.000000
Verbose
Unknown units of blocks
Arg: 1
Read 1000000 blocks
Added /home/ssd/big1
3.57%,  35720 read,    365 written, 28567.73kB/sec 3570.97 iops
6.14%,  25684 read,    276 written, 20519.77kB/sec 2564.97 iops
8.17%,  20270 read,    219 written, 16215.94kB/sec 2026.99 iops
9.66%,  14937 read,    131 written, 11945.84kB/sec 1493.23 iops
12.91%,  32494 read,    327 written, 25995.08kB/sec 3249.38 iops
14.06%,  11508 read,    118 written, 9206.33kB/sec 1150.79 iops
16.09%,  20292 read,    187 written, 16233.55kB/sec 2029.19 iops
17.57%,  14817 read,    141 written, 11853.49kB/sec 1481.69 iops
19.62%,  20515 read,    201 written, 16411.94kB/sec 2051.49 iops
21.90%,  22794 read,    214 written, 18222.39kB/sec 2277.80 iops
23.92%,  20207 read,    197 written, 16160.23kB/sec 2020.03 iops
26.11%,  21812 read,    213 written, 17427.32kB/sec 2178.42 iops
28.29%,  21852 read,    213 written, 17475.40kB/sec 2184.43 iops
30.73%,  24416 read,    234 written, 19507.42kB/sec 2438.43 iops
32.46%,  17298 read,    183 written, 13833.15kB/sec 1729.14 iops
33.25%,   7863 read,     87 written, 6290.35kB/sec  786.29 iops
35.67%,  24229 read,    213 written, 19383.12kB/sec 2422.89 iops
37.71%,  20397 read,    208 written, 16317.50kB/sec 2039.69 iops
39.61%,  19022 read,    200 written, 15217.51kB/sec 1902.19 iops
41.63%,  20190 read,    202 written, 16151.85kB/sec 2018.98 iops
44.00%,  23651 read,    266 written, 18913.60kB/sec 2364.20 iops
45.30%,  13066 read,    112 written, 10452.69kB/sec 1306.59 iops
47.37%,  20697 read,    218 written, 16557.55kB/sec 2069.69 iops
49.75%,  23726 read,    217 written, 18980.50kB/sec 2372.56 iops
51.55%,  18087 read,    170 written, 14469.56kB/sec 1808.69 iops
53.47%,  19194 read,    193 written, 15355.08kB/sec 1919.39 iops
55.30%,  18250 read,    205 written, 14599.93kB/sec 1824.99 iops
57.00%,  16999 read,    160 written, 13599.09kB/sec 1699.89 iops
58.79%,  17912 read,    180 written, 14329.56kB/sec 1791.19 iops
61.76%,  29694 read,    318 written, 23753.91kB/sec 2969.24 iops
62.96%,  12039 read,    113 written, 9631.16kB/sec 1203.90 iops
65.67%,  27048 read,    273 written, 21609.48kB/sec 2701.18 iops
67.00%,  13305 read,    130 written, 10639.63kB/sec 1329.95 iops
69.22%,  22229 read,    227 written, 17783.07kB/sec 2222.88 iops
71.13%,  19062 read,    170 written, 15249.52kB/sec 1906.19 iops
72.06%,   9299 read,     97 written, 7437.79kB/sec  929.72 iops
74.31%,  22492 read,    202 written, 17986.09kB/sec 2248.26 iops
76.66%,  23493 read,    219 written, 18768.77kB/sec 2346.10 iops
78.75%,  20979 read,    209 written, 16775.76kB/sec 2096.97 iops
80.68%,  19305 read,    194 written, 15428.97kB/sec 1928.62 iops
83.05%,  23670 read,    222 written, 18927.19kB/sec 2365.90 iops
84.59%,  15391 read,    169 written, 12299.46kB/sec 1537.43 iops
86.32%,  17246 read,    166 written, 13796.73kB/sec 1724.59 iops
88.33%,  20133 read,    201 written, 16106.22kB/sec 2013.28 iops
89.98%,  16561 read,    172 written, 13248.30kB/sec 1656.04 iops
92.81%,  28298 read,    252 written, 22627.87kB/sec 2828.48 iops
94.85%,  20388 read,    198 written, 16308.57kB/sec 2038.57 iops
96.75%,  18974 read,    178 written, 15179.09kB/sec 1897.39 iops
98.45%,  16956 read,    190 written, 13564.73kB/sec 1695.59 iops

-------------

/home/pgiosim-0.5/pgiosim  -w10 -a1 -v -b 1000000 /home/ssd/big1
Write Mode: 10%
Stallcheck at 1.000000
Verbose
Unknown units of blocks
Arg: 1
Read 1000000 blocks
Added /home/ssd/big1
2.01%,  20122 read,   1978 written, 16097.57kB/sec 2012.20 iops
2.01%,      3 read,      0 written,    2.40kB/sec    0.30 iops
2.01%,      3 read,      0 written,    2.40kB/sec    0.30 iops
2.01%,      3 read,      0 written,    2.40kB/sec    0.30 iops
3.82%,  18036 read,   1779 written, 14428.73kB/sec 1803.59 iops
4.03%,   2175 read,    209 written, 1739.98kB/sec  217.50 iops
4.03%,      3 read,      0 written,    2.40kB/sec    0.30 iops
4.03%,      2 read,      0 written,    1.60kB/sec    0.20 iops
4.04%,      4 read,      0 written,    3.20kB/sec    0.40 iops
4.04%,      4 read,      0 written,    3.20kB/sec    0.40 iops
5.62%,  15804 read,   1614 written, 12643.13kB/sec 1580.39 iops
5.62%,      3 read,      2 written,    2.40kB/sec    0.30 iops
5.62%,      4 read,      0 written,    3.20kB/sec    0.40 iops
5.62%,      3 read,      0 written,    2.40kB/sec    0.30 iops
5.62%,      3 read,      0 written,    2.40kB/sec    0.30 iops
6.86%,  12414 read,   1264 written, 9931.17kB/sec 1241.40 iops
6.86%,      3 read,      0 written,    2.40kB/sec    0.30 iops
6.86%,      2 read,      0 written,    1.60kB/sec    0.20 iops
7.18%,   3213 read,    343 written, 2570.39kB/sec  321.30 iops
8.34%,  11563 read,   1215 written, 9250.36kB/sec 1156.30 iops
8.34%,      3 read,      0 written,    2.40kB/sec    0.30 iops
8.34%,      4 read,      0 written,    3.20kB/sec    0.40 iops
8.34%,      3 read,      1 written,    2.40kB/sec    0.30 iops
8.64%,   3055 read,    276 written, 2443.98kB/sec  305.50 iops
10.57%,  19227 read,   1947 written, 15381.53kB/sec 1922.69 iops
10.57%,      3 read,      0 written,    2.40kB/sec    0.30 iops
10.57%,      4 read,      0 written,    3.20kB/sec    0.40 iops
10.57%,      3 read,      0 written,    2.40kB/sec    0.30 iops
10.57%,      2 read,      1 written,    1.60kB/sec    0.20 iops
10.57%,      7 read,      1 written,    5.60kB/sec    0.70 iops
11.32%,   7488 read,    752 written, 5990.38kB/sec  748.80 iops
11.32%,      3 read,      0 written,    2.40kB/sec    0.30 iops
13.32%,  20043 read,   1968 written, 16034.36kB/sec 2004.29 iops
13.32%,      3 read,      0 written,    2.40kB/sec    0.30 iops
13.32%,      4 read,      0 written,    3.20kB/sec    0.40 iops
13.32%,      3 read,      0 written,    2.40kB/sec    0.30 iops
13.32%,      4 read,      1 written,    3.20kB/sec    0.40 iops
13.32%,      5 read,      0 written,    4.00kB/sec    0.50 iops
15.12%,  17970 read,   1878 written, 14375.96kB/sec 1796.99 iops
15.12%,      4 read,      3 written,    3.20kB/sec    0.40 iops
15.12%,      5 read,      1 written,    4.00kB/sec    0.50 iops
^CCTRL-C Interrupt - stopping
!%*@#

--
Laurent "ker2x" Laborde
Sysadmin & DBA at http://www.over-blog.com/

Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
"Nicholson, Brad (Toronto, ON, CA)"
Date:
> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-
> owner@postgresql.org] On Behalf Of Laurent Laborde
> Sent: Tuesday, April 19, 2011 8:37 AM
> To: pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] postgresql random io test with 2 SSD Kingston
> V+100 500GB in (software) Raid1
>
> If we use them (unlikely), recovery in case of power outage isn't a
> problem, as we will use it on slave database (using Slony-I) that can
> be created/destroyed at will.
> And, anyway, our slave have fsync=off so the battery won't change
> anything in case of power outage :)

Are these on the same UPS?  If so, you have a failure case that could cause you to lose everything.

Brad.


Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Laurent Laborde
Date:
On Tue, Apr 19, 2011 at 3:21 PM, Nicholson, Brad (Toronto, ON, CA)
<bnicholson@hp.com> wrote:
>> -----Original Message-----
>> From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-
>> owner@postgresql.org] On Behalf Of Laurent Laborde
>> Sent: Tuesday, April 19, 2011 8:37 AM
>> To: pgsql-performance@postgresql.org
>> Subject: Re: [PERFORM] postgresql random io test with 2 SSD Kingston
>> V+100 500GB in (software) Raid1
>>
>> If we use them (unlikely), recovery in case of power outage isn't a
>> problem, as we will use it on slave database (using Slony-I) that can
>> be created/destroyed at will.
>> And, anyway, our slave have fsync=off so the battery won't change
>> anything in case of power outage :)
>
> Are these on the same UPS?  If so, you have a failure case that could cause you to lose everything.

Oh, not at all.
We're doing balancing/switch/failover between 2 different datacenter.
We can maintain (somewhat degraded) operation if one of the datacenter fail :)

--
Laurent "ker2x" Laborde
Sysadmin & DBA at http://www.over-blog.com/

On Apr 19, 2011, at 8:49 AM, Laurent Laborde wrote:

> Write Mode: 10%
> Stallcheck at 1.000000
> Verbose
> Unknown units of blocks
> Arg: 1
> Read 1000000 blocks
> Added /home/ssd/big1
> 2.01%,  20122 read,   1978 written, 16097.57kB/sec 2012.20 iops
> 2.01%,      3 read,      0 written,    2.40kB/sec    0.30 iops
> 2.01%,      3 read,      0 written,    2.40kB/sec    0.30 iops
> 2.01%,      3 read,      0 written,    2.40kB/sec    0.30 iops
> 3.82%,  18036 read,   1779 written, 14428.73kB/sec 1803.59 iops
> 4.03%,   2175 read,    209 written, 1739.98kB/sec  217.50 iops
> 4.03%,      3 read,      0 written,    2.40kB/sec    0.30 iops
> 4.03%,      2 read,      0 written,    1.60kB/sec    0.20 iops
> 4.04%,      4 read,      0 written,    3.20kB/sec    0.40 iops
> 4.04%,      4 read,      0 written,    3.20kB/sec    0.40 iops

The performance here looks like the old jmicron based ssds that had
absolutely abysmal performance - the intel x25s do not suffer like
this. The x25's however suffer from the power durability Greg has
mentioned.  (And they will eventually need to be security erase'd to
restore performance - you'll start getting major write stalls). Looks
like you were on the cusp of stalling here.

btw, yay pgiosim! :)

--
Jeff Trout <jeff@jefftrout.com>
http://www.stuarthamm.net/
http://www.dellsmartexitin.com/




Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Laurent Laborde
Date:
On Wed, Apr 20, 2011 at 2:39 PM, Jeff <threshar@torgo.978.org> wrote:
>
> The performance here looks like the old jmicron based ssds that had
> absolutely abysmal performance - the intel x25s do not suffer like this. The
> x25's however suffer from the power durability Greg has mentioned.  (And
> they will eventually need to be security erase'd to restore performance -
> you'll start getting major write stalls). Looks like you were on the cusp of
> stalling here.

A review of the V+100 on the excellent anandtech :
http://www.anandtech.com/show/4010/kingston-ssdnow-v-plus-100-review

> btw, yay pgiosim! :)

yay \o/

--
Laurent "ker2x" Laborde
Sysadmin & DBA at http://www.over-blog.com/

On 04/20/2011 09:01 AM, Laurent Laborde wrote:

> A review of the V+100 on the excellent anandtech :
> http://www.anandtech.com/show/4010/kingston-ssdnow-v-plus-100-review

That's horrifying. 4.9MB/s random writes? 19.7MB/s random reads? That's
at least an order of magnitude lower than other SSDs of that generation.
I can't imagine that would be very good for database usage patterns by
comparison. Especially with that aggressive garbage collection.

I mean... an old Indilinx OCZ Vertex has better performance than that.

--
Shaun Thomas
OptionsHouse | 141 W. Jackson Blvd. | Suite 800 | Chicago IL, 60604
312-676-8870
sthomas@peak6.com

______________________________________________

See  http://www.peak6.com/email_disclaimer.php
for terms and conditions related to this email

Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Laurent Laborde
Date:
On Wed, Apr 20, 2011 at 5:40 PM, Shaun Thomas <sthomas@peak6.com> wrote:
> On 04/20/2011 09:01 AM, Laurent Laborde wrote:
>
>> A review of the V+100 on the excellent anandtech :
>> http://www.anandtech.com/show/4010/kingston-ssdnow-v-plus-100-review
>
> That's horrifying. 4.9MB/s random writes? 19.7MB/s random reads? That's at
> least an order of magnitude lower than other SSDs of that generation. I
> can't imagine that would be very good for database usage patterns by
> comparison. Especially with that aggressive garbage collection.
>
> I mean... an old Indilinx OCZ Vertex has better performance than that

We just orderer 2 Corsair C300 240GB to compare performance and see if
the difference is as huge as claimed on anandtech's benchmark :)

--
Laurent "ker2x" Laborde
Sysadmin & DBA at http://www.over-blog.com/

Re: postgresql random io test with 2 SSD Kingston V+100 500GB in (software) Raid1

From
Marinos Yannikos
Date:
Am 19.04.2011 11:15, schrieb Laurent Laborde:
> Soft RAID1 (md)
> ext3

We have experimented a bit with Postgres and ext3 (with and without Linux
software RAID1) and have found that since somewhere after 2.6.18, it has been
prohibitively slow and causing high latencies during buffer flushes. You will
probably see a significant improvement with ext4 (mkfs.ext4, not just remount as
ext4, which is also possible).

Also, you need to make sure that your blocks are properly aligned with SSDs,
that might explain low random I/O performance. See
http://www.nuclex.org/blog/personal/80-aligning-an-ssd-on-linux and

http://www.ocztechnologyforum.com/forum/showthread.php?54379-Linux-Tips-tweaks-and-alignment&p=373226&viewfull=1#post373226

for example.

Regards,
  Marinos