And some out-of-the-box thinking. Similarity is one
aspect of why redundancy fails. When the Browns Ferry
nuclear reactor almost melted down in the seventies, it
had redundant systems. The control lines ran down the
same tray. When some not-to-bright maintenance engineers
were checking for leaks with a lit candle, they forgot
that leaks suck as well as blow. The insulation caught
fire at the point where the control lines lay side by
side, redundant but vulnerable. Vulnerabilities are a
different class of error handling which is why some
Internet systems are demonstrating such poor results
when under attack.
len
From: Nathan Young [mailto:]
I guess the main point is that effective redundancy should provide not
just duplicate systems, but rather two or more entirely different ways of
accomplishing the same thing.
