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From: Joshua D. Drake <jd@commandprompt.com>
To: Alex Deucher <alexdeucher@gmail.com>
Cc: Jeff Frost <jeff@frostconsultingllc.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: strange performance regression between 7.4 and 8.1
Date: Thu, 01 Mar 2007 18:21:36 -0800
Message-ID: <45E78A30.1030408@commandprompt.com> (raw)
In-Reply-To: <a728f9f90703011747g6512a8d3p47c9cc2101e0b233@mail.gmail.com>
References: <a728f9f90703011244r577d56d7y422ab4bd71bb760e@mail.gmail.com>
	<45E73C90.2080206@commandprompt.com>
	<a728f9f90703011306u674e766t9c158723bdb0d43c@mail.gmail.com>
	<Pine.LNX.4.64.0703011334410.3892@discord.home.frostconsultingllc.com>
	<a728f9f90703011350w1f2f1f9u69b1783461aabe3@mail.gmail.com>
	<Pine.LNX.4.64.0703011353520.3892@discord.home.frostconsultingllc.com>
	<a728f9f90703011412kd8c8535wad5058319d07ede0@mail.gmail.com>
	<Pine.LNX.4.64.0703011633390.3892@discord.home.frostconsultingllc.com>
	<a728f9f90703011744s5e54bd4aq905e0fcc41811e90@mail.gmail.com>
	<45E78210.9030401@commandprompt.com>
	<a728f9f90703011747g6512a8d3p47c9cc2101e0b233@mail.gmail.com>

Alex Deucher wrote:
> On 3/1/07, Joshua D. Drake <jd@commandprompt.com> wrote:
>> \
>> >> Is the SAN being shared between the database servers and other
>> >> servers?  Maybe
>> >> it was just random timing that gave you the poor write performance on
>> >> the old
>> >> server which might be also yielding occassional poor performance on
>> >> the new
>> >> one.
>> >>
>> >
>> > The direct attached scsi discs on the old database server we getting
>> > 45MBps not the SAN.  The SAN got 62/145Mbps, which is not as bad.
>>
>> How many spindles you got in that SAN?
> 
> 105 IIRC.

You have 105 spindles are you are only get 62megs on writes? That seems
about half what you should be getting. (at least).

Joshua D. Drake


> 
> Alex
> 


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