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Subject: Re: Request for feedback on hardware for a new database server
From: Steve Atkins <steve@blighty.com>
In-Reply-To: <871v25jlnb.fsf@googlemail.com>
Date: Thu, 17 Mar 2011 19:05:46 -0700
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Message-Id: <CF457359-D3EC-41D7-B46E-CE38B9D1F158@blighty.com>
References: <871v25jlnb.fsf@googlemail.com>
To: PostgreSQL Performance <pgsql-performance@postgresql.org>


On Mar 17, 2011, at 5:51 PM, Oliver Charles wrote:

> Hello,
> 
> At MusicBrainz we're looking to get a new database server, and are
> hoping to buy this in the next couple of days. I'm mostly a software
> guy, but I'm posting this on behalf of Rob, who's actually going to be
> buying the hardware. Here's a quote of what we're looking to get:
> 
>    I'm working to spec out a bad-ass 1U database server with loads of
>    cores (12), RAM (24GB) and drives (4 SAS) in a hardware RAID-1,0
>    configuration:
> 
>    1 * SuperMicro 2016R-URF, 1U, redundant power supply, 4 SATA/SAS
>    drive bays 2
>    2 * Intel Xeon X5650 Westmere 2.66GHz 12MB L3 Cache LGA 1366 95W
>    Six-Core Server Processor 2
>    2 * Crucial 24GB (3 x 4GB) DDR3 SDRAM ECC Registered DDR3 1333,
>    CT3KIT51272BV1339 1
>    1 * LSI MegaRAID SATA/SAS 9260-4i ($379) (linux support [1])
>    or
>    1 * HighPoint RocketRAID 4320 PCI-Express x8 ($429)
>    or
>    1 * Adaptec RAID 3405 controller ($354)
>    4 * Fujitsu MBA3147RC 147GB 15000 RPM

> 
>    That's it -- anyone have any feedback?


I'm no expert, but...

That's very few drives. Even if you turn them into a single array
(rather than separating out a raid pair for OS and a raid pair
for WAL and raid 10 array for data) that's going to give you
very little IO bandwidth, especially for typical random
access work.

Unless your entire database active set fits in RAM I'd expect your
cores to sit idle waiting on disk IO much of the time.

Don't forget that you need a BBU for whichever RAID controller
you need, or it won't be able to safely do writeback caching, and
you'll lose a lot of the benefit.

Cheers,
  Steve