Date: Sat, 26 May 2007 08:43:15 -0400
From: Michael Stone <mstone+postgres@mathom.us>
Subject: Re: ECC RAM really needed?
In-reply-to: <4657912B.3000508@emolecules.com>
To: Craig James <craig_james@emolecules.com>
Cc: pgsql-performance@postgresql.org
Mail-followup-to: Craig James <craig_james@emolecules.com>,
	pgsql-performance@postgresql.org
Message-id: <20070526124313.GU1785@mathom.us>
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On Fri, May 25, 2007 at 06:45:15PM -0700, Craig James wrote:
>We're thinking of building some new servers.  We bought some a while back 
>that have ECC (error correcting) RAM, which is absurdly expensive compared 
>to the same amount of non-ECC RAM.  Does anyone have any real-life data 
>about the error rate of non-ECC RAM, and whether it matters or not?  In my 
>long career, I've never once had a computer that corrupted memory, or at 
>least I never knew if it did. 

...because ECC RAM will correct single bit errors. FWIW, I've seen *a 
lot* of single bit errors over the years. Some systems are much better 
about reporting than others, but any system will have occasional errors. 
Also, if a stick starts to go bad you'll generally be told about with 
ECC memory, rather than having the system just start to flake out. 

Mike Stone