Why do we use facilities with EPO's?

Wed Jul 25 21:10:10 UTC 2007

On Jul 25, 2007, at 3:35 PM, Patrick W. Gilmore wrote:

>
> On Jul 25, 2007, at 2:03 PM, Tuc at T-B-O-H.NET wrote:
>
>>> If they can be avoided, why do we put up with them?  Do we really
>>> want our colo in downtown San Francisco bad enough to take the risk
>>> of having a single point of failure?  How can we, as engineers, ask
>>> questions about how many generators, how much fuel, and yet take
>>> for granted that there is one button on the wall that makes it all
>>> turn off?  Is it simply that having colo in the middle of the city
>>> is so convenient that it overrides the increased cost and the  
>>> reduced
>>> redundancy that are necessitated by that location?
>>>
>> 	You forgot the default "Single Point of Failure" in anything..
>>
>> 			HUMANS.
>
> The earth is a SPoF.  Let's put DCs on the moon.
>
> Besides, safety always overrides convenience.  And I don't think  
> that is a bad trade off.

Me neither...

Having multiple redundant sites (and a well designed network between  
them) is almost always going to be better than a single, wildly  
redundant site. No matter how much redundancy you build into a single  
site, you cannot (realistically) engineer away things like floods,  
etc. Planning your redundancy and testing it though is very important...

Random anecdote (from a friend, I don't know if it true or not):
Back in the day (before cheap international circuits), a very large  
financial in New York needed connectivity to some branches in Europe,  
so they bought some capacity on a satellite transponder and built  
their own ground-station (not cheap) fairly close to NY. They then  
realized that the needed a redundant ground station in case the first  
one failed or something similar, so the built a second ground- 
station, just outside Jersey City....

One of the satellite connectivity failure modes is... rain fade.....

W

>
> -- 
> TTFN,
> patrick
>
>

-- 
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