That logic is completely false and you contradict yourself.

Allowing for multiple points of failure does not mean that something is
less
reliable as you have described.  It means that if/when one fails, the
other
will still be available.

Using your example of a power supply lasting 10 years, that would
translate to 2 failures in 10 years, not 1 failure in 5 years.  

I think you understand the concepts, as your "best" solution is to have
multiple points of failure with failover using CARP.

Jim O'Donald


-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
Of chefren
Sent: Wednesday, August 03, 2005 12:47 PM
To: misc@openbsd.org
Subject: Re: Ammunition needed to defend OpenBSD/pf

On 08/03/05 19:25, Shawn K. Quinn wrote:

> You mean having the DSL router and modem be in the same physical box,
> thus introducing a single point of failure? That's a huge minus.

??? You would prefer a milion boxes for each individual transistor or
logic gate?

Two boxes have two CPU's, two power supplies etc in the same production
line and 
the total is thus =less= reliable than a single box solution.

If the power supplies are equal and each statistically break down once
in ten 
years in total that becomes once in five years.


By the way, the same applies for RAID, more concurrent harddisks
definitely 
means =more often broken drives=. Although the system won't break down
if well 
designed, you still have to do more repairs. Five drives instead of one:
Five 
times as much disks to repair/replace.

Good is often to have a spare, pre installed(!), "DSL router and modem",
better 
is to have a concurrent and tested(!) backup channel. Best is to have a
working 
backup channel: CARP!

+++chefren

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