It’s the season for coughs and sniffles, and last week I took my turn. I went to bed one night with a stuffy nose, and it got me thinking about software.

What’s the connection between sniffles and software, you ask?

Let’s talk redundancy. It’s a familiar technique in software design, but I believe we compartmentalize it too much under the special topic of “high availability”–as if only when that’s an explicit requirement do we need to pay any attention.

Redundancy in nature

Mother Nature’s use of redundancy is so pervasive that we may not even realize it’s at work. We could learn a thing or two from how she weaves it–seamlessly, consistently, tenaciously–into the tapestry of life.

Redundancy had everything to do with the fact that I didn’t asphyxiate as I slept with a cold. People have more than one sinus, so sleeping with a few of them plugged up isn’t life-threatening. If nose breathing isn’t an option, we can always open our mouths. We have two lungs, not one–and each consists of huge numbers of alveoli that does part of the work of exchanging oxygen and carbon dioxide. Continue reading →