From: Greg Smith <greg@2ndquadrant.com>
To: stanimir petrov <cristal_reaver@abv.bg>
Cc: pgsql-performance@postgresql.org
Subject: Re: tune memory usage for master/slave nodes in cluster
Date: Wed, 21 Jul 2010 11:08:36 -0400
Message-ID: <4C470D74.8010509@2ndquadrant.com> (raw)
In-Reply-To: <609756248.1423.1279716124148.JavaMail.apache@mail71.abv.bg>
References: <609756248.1423.1279716124148.JavaMail.apache@mail71.abv.bg>
stanimir petrov wrote:
> Now the servers are dual core CPU 2.6 with 1.7 GB RAM and i standart
> disk. (the small instance from AWS)
You're never going to be able to tune for writing data fast on a AWS
environment; there just isn't enough disk throughput available. If this
application really does take off the way you expect it to, don't be
surprised to find you have to move it to real hardware to keep up.
Dedicated database servers tend to have tens of disks in them to keep up
with the sort of load you're expecting, and you just can't get that in a
cloud environment. You can do some work to improve I/O using multiple
storage instances;
http://blog.endpoint.com/2010/02/postgresql-ec2-ebs-raid0-snapshot.html
is a good introduction to that.
The basic tuning advice you're looking for is available at
http://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server
If you are trying to get faster writes out of AWS hardware, you may have
to turn off synchronous_commit to accomplish that. That has some
potential lost transaction downsides, but simple disks just can't write
data that fast so it may be the only way to make this work well.
--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com www.2ndQuadrant.us
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To: pgsql-performance@postgresql.org
Cc: greg@2ndquadrant.com, cristal_reaver@abv.bg
Subject: Re: tune memory usage for master/slave nodes in cluster
In-Reply-To: <4C470D74.8010509@2ndquadrant.com>
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