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Message-ID: <b41c75520702140119l2dda132cta47e38ecae1f7a49@mail.gmail.com>
Date: Wed, 14 Feb 2007 10:19:52 +0100
From: "Claus Guttesen" <kometen@gmail.com>
To: "Kenji Morishige" <kenjim@juniper.net>
Subject: Re: quad or dual core Intel CPUs
Cc: pgsql-performance@postgresql.org
In-Reply-To: <20070213194610.GA10789@juniper.net>
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References: <20070213194610.GA10789@juniper.net>

> I am about to pull the trigger on a new machine after analyzing some
> discussions I posted here last year.  I've been trying to spec out a reliable
> and powerfull enough machine where I won't have to replace it for some time.
> Currently I've been using a dual Xeon 3.06ghz with 4GB of ram and utilizing a
> RAID 1+0 configuration over a total 6 SCSI disks asside from the OS partition.
> We have about 10GB of data and will probably scale at about 1GB per month. We
> currently average about 200 queries per second and the 15 minute load average
> is about .30.  I am running FreeBSD 6.1.
>
> At the end of last year, I specced out a new machine to replace this box. At
> that time, the quad core 2.66ghz were not available from my vendor and I was
> not planning to go that route. Now that they are available, I am considering
> the option. The main question here is whether FreeBSD 6.X and PostgreSQL 8.1
> would be able to take advantage of the quad core and perform better than the
> 3.0Ghz dual core.  The reason I ask is due to some conflicting benchmarking
> results I see posted on the spec.org website.
>
> Here is the full specification of the new box I hope to build and run FreeBSD
> 6.X and PostgreSQL on:
>
> - SuperMicro Dual Xeon X7DBE+ motherboard
>   + 2 x Quad Core X5355 2.66Ghz
>     OR
>   + 2 x Dual Core 5160 3.0Ghz
>
> - 8 x 1GB PC2-4200 fully buffered DIMM
>
> - LSI MegaRAID SAS 8408E w/BBU 256MB
>
> - 16 x 73GB SAS disk
>
> So, question #1, to go dual core or quad core?  Quad core in theory seems to
> scale the machine's processing potential by almost a factor of two.

We recently migrated from a four way opteron @ 2 GHz with 8 GB to a
four way woodcrest @ 3 GHz (HP DL380 G5) with 16 GB ram. I also
upgraded FreeBSD from 6.0 to 6.2 and did a minor upgrade of postgresql
from 7.4.9 to 7.4.12. The change was tremendous, the first few hours
of after it went into production I had to doublecheck that our website
worked, since the load was way below 1 whereas the load had been
almost 100 during peak.

I don't have any financial ties to HP but building a server from
scratch may not be worth it, rather than spending time assemling all
the different parts yourself I would suggest you get a server from one
vendor who build a server according to your specs.

The DL380 (also) has a 256 MB bbc controller, the nic works flawlessly
with FreeBSD 6.2, all parts are well integrated, the frontbay can
accomodate 8 146 GB SAS drives. This server is wellsuited as a
postgresql-server.

Approx. 200 reqest a sec. should be a problem unless the queries are heavy.

regards
Claus