Re: [gentoo-security] System knockout :-(

[Andrew Joyce]

On Mon, Apr 05, 2004 at 06:41:47PM -0700, Julio Cazares wrote:
> Raid also does not offer a better offering because it multiplies the
> probability of failure 2 times.
>
> RAID, I believe it works best on their native "Quality" server design
> and
> manufacture: SCSI.
>
> Putting for example 4 IDE HD's In 2 RAID channels stressed the Power
> supply (Chinese and consumer conceived also), and this probably lead
> to
> disaster on the long run.
>
> So, One SCSI, without RAID, is better (Thinking on probabilities), Due
> to
> the manufacture Quality assurance differences.
>
> It is the same reason because the airplanes are safer with less
> motors,
> (Contrary of the public opinion and feeling). Or in a car, Purchase
> two
> "Unbranded" tires instead of a new Michelin.
>
> Best Regards.
>
> Julio.
 
Julio,

I don't believe I understand your rationale for claiming that RAID is
going to increase the probability of failures.  If you consider the case
where each drive alone has a a 10% chance of failing, two drives
simultaneously failing should have a 1% chance of happening.  This is a
fairly great reduction in the chance of a critical data failure.

Similarly, in a plane, virtually every control system is in some manner
redundant (at least in my recollection -- I'm trying to recall the
discussions on plane regulations and failure modes from my first year
engineering class).  This redundancy means that if one system fails
there is another to take over and guide the plane to safety.  Even if
the systems are identical with a 1% chance of failure this reduces the
probably of the plane becoming inoperable to 0.01%, or 1 in 10000
compared to 1 in 100.

I can hardly see how this is increasing the chances of your plane
crashing to the ground.

Andrew

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