From: Greg Smith <gsmith@gregsmith.com>
To: alan bryan <alan.bryan@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Performance tuning on FreeBSD
Date: Mon, 3 Mar 2008 20:11:42 -0500 (EST)
Message-ID: <Pine.GSO.4.64.0803032005020.23114@westnet.com> (raw)
In-Reply-To: <892916310803031539scffd5bchcce5a848b3a57a32@mail.gmail.com>
References: <892916310803031539scffd5bchcce5a848b3a57a32@mail.gmail.com>
On Mon, 3 Mar 2008, alan bryan wrote:
>> pgbench -c 100 -t 1000 testdb
> tps = 558.013714 (excluding connections establishing)
>
> Just for testing, I tried turning off fsync and got:
> tps = 4061.662041 (excluding connections establishing)
This is odd. ~500 is what I expect from this test when there is no write
cache to accelerate fsync, while ~4000 is normal for your class of
hardware when you have such a cache. Since you say your 3Ware card is
setup with a cache and a BBU, that's suspicious--you should be able to get
around 4000 with fsync on. Any chance you have the card set to
write-through instead of write-back? That's the only thing that comes to
mind that would cause this.
--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD
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To: pgsql-performance@postgresql.org
Cc: gsmith@gregsmith.com, alan.bryan@gmail.com
Subject: Re: Performance tuning on FreeBSD
In-Reply-To: <Pine.GSO.4.64.0803032005020.23114@westnet.com>
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