From: | Greg Smith <gsmith(at)gregsmith(dot)com> |
---|---|
To: | alan bryan <alan(dot)bryan(at)gmail(dot)com> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: Performance tuning on FreeBSD |
Date: | 2008-03-04 01:11:42 |
Message-ID: | Pine.GSO.4.64.0803032005020.23114@westnet.com |
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Thread: | |
Lists: | pgsql-performance |
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(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD
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