User-Agent: Microsoft-Entourage/11.2.5.060620
Date: Tue, 15 Aug 2006 23:17:32 -0700
Subject: Re: Dell PowerEdge 2950 performance
From: "Luke Lonergan" <llonergan@greenplum.com>
To: "Bucky Jordan" <bjordan@lumeta.com>, "Vivek Khera" <vivek@khera.org>,
	"Pgsql-Performance ((E-mail))" <pgsql-performance@postgresql.org>
Message-ID: <C108068C.2E48B%llonergan@greenplum.com>
Thread-Topic: [PERFORM] Dell PowerEdge 2950 performance
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Cool - seems like the posters caught that "auto memory pick" problem before
you posted, but you got the 16GB/8k parts right.

Now we're looking at realistic numbers - 790 seeks/second, 244MB/s
sequential write, but only 144MB/s sequential reads, perhaps 60% of what it
should be.

Seems like a pretty good performer in general - if it was Linux I'd play
with the max readahead in the I/O scheduler to improve the sequential reads.

- Luke


On 8/15/06 1:21 PM, "Bucky Jordan" <bjordan@lumeta.com> wrote:

> Luke,
> 
> For some reason it looks like bonnie is picking a 300M file.
> 
>> bonnie++ -d bonnie
> Version  1.03       ------Sequential Output------ --Sequential Input-
> --Random-
>                     -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
>    300M 179028  99 265358  41 270175  57 167989  99 +++++ +++
> +++++ +++
>                     ------Sequential Create------ --------Random
> Create--------
>                     -Create-- --Read--- -Delete-- -Create-- --Read---
> -Delete--
>               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
> /sec %CP
>                  16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
> +++++ +++
> ,300M,179028,99,265358,41,270175,57,167989,99,+++++,+++,+++++,+++,16,+++
> ++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++
> 
> So here's results when I force it to use a 16GB file, which is twice the
> amount of physical ram in the system:
> 
>> bonnie++ -d bonnie -s 16000:8k
> Version  1.03       ------Sequential Output------ --Sequential Input-
> --Random-
>                     -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
>  16000M 158539  99 244430  50 58647  29 83252  61 144240  21
> 789.8   7
>                     ------Sequential Create------ --------Random
> Create--------
>                     -Create-- --Read--- -Delete-- -Create-- --Read---
> -Delete--
>               files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
> /sec %CP
>                  16  7203  54 +++++ +++ +++++ +++ 24555  42 +++++ +++
> +++++ +++
> ,16000M,158539,99,244430,50,58647,29,83252,61,144240,21,789.8,7,16,7203,
> 54,+++++,+++,+++++,+++,24555,42,+++++,+++,+++++,+++
> 
> ... from Vivek...
> which is an issue with freebsd and bonnie++ since it doesn't know
> that freebsd can use large files natively (ie, no large file hacks
> necessary).  the freebsd port of bonnie takes care of this, if you
> use that instead of compiling your own.
> ...
> 
> Unfortunately I had to download and build by hand, since only bonnie++
> 1.9x is available in BSD 6.1 ports when I checked.
> 
> One other question- would the following also be mostly a test of RAM? I
> wouldn't think so since it should force it to sync to disk...
> time bash -c "(dd if=/dev/zero of=/data/bigfile count=125000 bs=8k &&
> sync)"
> 
> Oh, and while I'm thinking about it, I believe Postgres uses 8k data
> pages correct? On the RAID, I'm using 128k stripes. I know there's been
> posts on this before, but is there any way to tell postgres to use this
> in an effective way?
> 
> Thanks,
> 
> Bucky
> 
> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Vivek Khera
> Sent: Tuesday, August 15, 2006 3:18 PM
> To: Pgsql-Performance ((E-mail))
> Subject: Re: [PERFORM] Dell PowerEdge 2950 performance
> 
> 
> On Aug 15, 2006, at 2:50 PM, Luke Lonergan wrote:
> 
>> I don't know why I missed this the first time - you need to let
>> bonnie++
>> pick the file size - it needs to be 2x memory or the results you
>> get will
>> not be accurate.
> 
> which is an issue with freebsd and bonnie++ since it doesn't know
> that freebsd can use large files natively (ie, no large file hacks
> necessary).  the freebsd port of bonnie takes care of this, if you
> use that instead of compiling your own.
> 
>