From owner-freebsd-questions  Wed May 26  3:37:44 1999
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Date: Wed, 26 May 1999 01:46:36 +0200
From: Juergen Nickelsen <jnickelsen@acm.org>
To: Graeme Tait <graeme@echidna.com>
Cc: freebsd-questions@FreeBSD.ORG
Subject: Re: 100% dependability/failsafe/security/hardware
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--On Die, 25. Mai 1999 11:39 -0400 Graeme Tait <graeme@echidna.com>
wrote:

> > > 3. How to provide 100% failsafe system?
> > 
> > *All* hardware redundant: CPUs, RAM, secondary storage, data paths,
> > power supplies, fans, UPSs, etc.; proactive hardware monitoring
> 
> <snip of description of highly reliable $$$y$tem>
> 
> I would say you need to start this project with an acceptable
> downtime target. There is no such thing as perfection, and you can't
> engineer an appropriate solution without quantifying your
> requirements. Beyond a certain point, the reliability target becomes
> the primary driver of design and cost.

You are right, of course. I should have been more explicit about the
point of my message, that real *100* % reliability is more than most
people want to pay for, and more than most people need (given the
cost). The goal should be, as you said, "acceptable downtime".

Greetings, Juergen.



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