From: Bruce Momjian <pgman@candle.pha.pa.us>
Message-Id: <200605101435.k4AEZxc13602@candle.pha.pa.us>
Subject: Re: [GENERAL] Arguments Pro/Contra Software Raid
In-Reply-To: <29EA6D53-F41E-4A09-B5CA-EFD182AB9772@khera.org>
To: Vivek Khera <vivek@khera.org>
Date: Wed, 10 May 2006 10:35:59 -0400 (EDT)
CC: "Pgsql-Performance ((E-mail))" <pgsql-performance@postgresql.org>
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Vivek Khera wrote:
> 
> On May 10, 2006, at 12:41 AM, Greg Stark wrote:
> 
> > Well, dollar for dollar you would get the best performance from  
> > slower drives
> > anyways since it would give you more spindles. 15kRPM drives are  
> > *expensive*.
> 
> Personally, I don't care that much for "dollar for dollar" I just  
> need performance.  If it is within a factor of 2 or 3 in price then  
> I'll go for absolute performance over "bang for the buck".

That is really the issue.  You can buy lots of consumer-grade stuff and
work just fine if your performance/reliability tolerance is high enough.

However, don't fool yourself that consumer and server-grade hardware is
internally the same, or has the same testing.

I just had a Toshiba laptop drive replaced last week (new, not
refurbished), only to have it fail this week.  Obviously there isn't
sufficient burn-in done by Toshiba, and I don't fault them because it is
a consumer laptop --- it fails, they replace it.  For servers, the
downtime usually can't be tolerated, while consumers usually can
tolerate significant downtime.

I have always purchased server-grade hardware for my home server, and I
think I have had one day of hardware downtime in the past ten years. 
Consumer hardware just couldn't do that.

As one data point, most consumer-grade IDE drives are designed to be run
only 8 hours a day.  The engineering doesn't anticipate 24-hour
operation, and that trade-off passes all the way through the selection
of componients for the drive, which generates sigificant cost savings.

-- 
  Bruce Momjian   http://candle.pha.pa.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +