From: Kevin Grittner <Kevin.Grittner@wicourts.gov>
To: Joshua Drake <jd@commandprompt.com>
To: pgsql-performance@postgresql.org
Subject: Re: Background writer configuration
Date: Wed, 15 Mar 2006 14:43:01 -0600
Message-ID: <441827F5.EE98.0025.0@wicourts.gov> (raw)
In-Reply-To: <200603151154.33504.jd@commandprompt.com>
References: <44181A11.EE98.0025.0@wicourts.gov>
<200603151154.33504.jd@commandprompt.com>
>>> On Wed, Mar 15, 2006 at 1:54 pm, in message
<200603151154.33504.jd@commandprompt.com>, "Joshua D. Drake"
<jd@commandprompt.com> wrote:
>> I then did some calculations, based on the sustained write speed of
our
>> drive array (as measured by copying big files to it), and we tried
>> this:
>>
>> bgwriter_lru_percent = 20.0
>> bgwriter_lru_maxpages = 200
>> bgwriter_all_percent = 10.0
>> bgwriter_all_maxpages = 600
>>
>> This almost totally eliminated the clusters of timeouts, and caused
the
>> transaction application rate to increase by a factor of eight over
the
>> already- improved speed. (That is, we were running 30 to 35 times
as
>> many transactions per minute into the database, compared to the
default
>> background writer configuration.) I'm going to let these settings
>> settle in for a week or two before we try adjusting them further (to
see
>> if we can eliminate those last few timeouts of this type).
>
>
> Can you tell us what type of array you have?
Each machine has a RAID5 array of 13 (plus one hot spare)
15,000 RPM Ultra 320 SCSI drives
2 machines using IBM ServRaid6M battery backed caching controllers
2 machines using IBM ServRaid4MX battery backed caching controllers
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To: pgsql-performance@postgresql.org
Cc: Kevin.Grittner@wicourts.gov, jd@commandprompt.com
Subject: Re: Background writer configuration
In-Reply-To: <441827F5.EE98.0025.0@wicourts.gov>
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