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Re: Two identical systems, radically different performance

From: Craig James <cjames(at)emolecules(dot)com>
To: Evgeny Shishkin <itparanoia(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Two identical systems, radically different performance
Date: 2012-10-08 22:42:33
Message-ID: CAFwQ8rcXE3=2KLgYKO_x+7cMpttwabV0EwEeDSoVZWP7Kx6RGg@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Mon, Oct 8, 2012 at 3:33 PM, Evgeny Shishkin <itparanoia(at)gmail(dot)com>wrote:

>
> On Oct 9, 2012, at 1:45 AM, Craig James <cjames(at)emolecules(dot)com> wrote:
>
> One dramatic difference I noted via vmstat.  On the old server, the I/O
> load during the bonnie++ run was steady, like this:
>
> procs -----------memory---------- ---swap-- -----io---- -system--
> ----cpu----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id
> wa
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id
> wa
>  0  2  71800 2117612  17940 9375660    0    0 82948 81944 1992 1341  1  3
> 86 10
>  0  2  71800 2113328  17948 9383896    0    0 76288 75806 1751 1167  0  2
> 86 11
>  0  1  71800 2111004  17948 9386540   92    0 93324 94232 2230 1510  0  4
> 86 10
>  0  1  71800 2106796  17948 9387436  114    0 67698 67588 1572 1088  0  2
> 87 11
>  0  1  71800 2106724  17956 9387968   50    0 81970 85710 1918 1287  0  3
> 86 10
>  1  1  71800 2103304  17956 9390700    0    0 92096 92160 1970 1194  0  4
> 86 10
>  0  2  71800 2103196  17976 9389204    0    0 70722 69680 1655 1116  1  3
> 86 10
>  1  1  71800 2099064  17980 9390824    0    0 57346 57348 1357  949  0  2
> 87 11
>  0  1  71800 2095596  17980 9392720    0    0 57344 57348 1379  987  0  2
> 86 12
>
> But the new server varied wildly during bonnie++:
>
> procs -----------memory---------- ---swap-- -----io---- -system--
> ----cpu----
>  r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id
> wa
>  0  1      0 4518352  12004 7167000    0    0 118894 120838 2613 1539  0
> 2 93  5
>  0  1      0 4517252  12004 7167824    0    0  52116  53248 1179  793  0
> 1 94  5
>  0  1      0 4515864  12004 7169088    0    0  46764  49152 1104  733  0
> 1 91  7
>  0  1      0 4515180  12012 7169764    0    0  32924  30724  750  542  0
> 1 93  6
>  0  1      0 4514328  12016 7170780    0    0  42188  45056 1019  664  0
> 1 90  9
>  0  1      0 4513072  12016 7171856    0    0  67528  65540 1487  993  0
> 1 96  4
>  0  1      0 4510852  12016 7173160    0    0  56876  57344 1358  942  0
> 1 94  5
>  0  1      0 4500280  12044 7179924    0    0  91564  94220 2505 2504  1
> 2 91  6
>  0  1      0 4495564  12052 7183492    0    0 102660 104452 2289 1473  0
> 2 92  6
>  0  1      0 4492092  12052 7187720    0    0  98498  96274 2140 1385  0
> 2 93  5
>  0  1      0 4488608  12060 7190772    0    0  97628 100358 2176 1398  0
> 1 94  4
>  1  0      0 4485880  12052 7192600    0    0 112406 114686 2461 1509  0
> 3 90  7
>  1  0      0 4483424  12052 7195612    0    0  64678  65536 1449  948  0
> 1 91  8
>  0  1      0 4480252  12052 7199404    0    0  99608 100356 2217 1452  0
> 1 96  3
>
>
> Also note the difference in free/cache distribution. Unless you took these
> numbers in completely different stages of bonnie++.
>
>
The old server is in production and is running Apache/Postgres requests.

Craig

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