Re: Two identical systems, radically different performance

On Mon, Oct 8, 2012 at 2:57 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:
>
> I tested both the RAID10 data disk and the RAID1 xlog disk with bonnie++.
> The xlog disks were almost identical in performance. The RAID10 pg-data
> disks looked like this:
>
> Old server:
> Version 1.96 ------Sequential Output------ --Sequential Input-
> --Random-
> Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
> --Seeks--
> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
> /sec %CP
> xenon 24064M 687 99 203098 26 81904 16 3889 96 403747 31
> 737.6 31
> Latency 20512us 469ms 394ms 21402us 396ms
> 112ms
> Version 1.96 ------Sequential Create------ --------Random
> Create--------
> xenon -Create-- --Read--- -Delete-- -Create-- --Read---
> -Delete--
> files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
> /sec %CP
> 16 15953 27 +++++ +++ +++++ +++ +++++ +++ +++++ +++
> +++++ +++
> Latency 43291us 857us 519us 1588us 37us
> 178us
>
> 1.96,1.96,xenon,1,1349726125,24064M,,687,99,203098,26,81904,16,3889,96,403747,31,737.6,31,16,,,,,15953,27,+++++,+++,+++++,++\
>
> +,+++++,+++,+++++,+++,+++++,+++,20512us,469ms,394ms,21402us,396ms,112ms,43291us,857us,519us,1588us,37us,178us
>
>
> New server:
> Version 1.96 ------Sequential Output------ --Sequential Input-
> --Random-
> Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
> --Seeks--
> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
> /sec %CP
> zinc 24064M 862 99 212143 54 96008 14 4921 99 279239 17
> 752.0 23
> Latency 15613us 598ms 597ms 2764us 398ms
> 215ms
> Version 1.96 ------Sequential Create------ --------Random
> Create--------
> zinc -Create-- --Read--- -Delete-- -Create-- --Read---
> -Delete--
> files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
> /sec %CP
> 16 20380 26 +++++ +++ +++++ +++ +++++ +++ +++++ +++
> +++++ +++
> Latency 487us 627us 407us 972us 29us
> 262us
>
> 1.96,1.96,zinc,1,1349722017,24064M,,862,99,212143,54,96008,14,4921,99,279239,17,752.0,23,16,,,,,20380,26,+++++,+++,+++++,+++\
>
> ,+++++,+++,+++++,+++,+++++,+++,15613us,598ms,597ms,2764us,398ms,215ms,487us,627us,407us,972us,29us,262us
>
>
> Sequential Input on the new one is 279MB/s, on the old 400MB/s.
>
>
But why? What have I overlooked?

Thanks,
Craig