Patterns for Resilient Architecture — Part 4

Caching for Resiliency

As noted in the New York Times article: “For Impatient Web Users, an Eye Blink Is Just Too Long to Wait,” a user’s perception of quality and a good experience is directly correlated to the speed at which content is delivered to them. Speed matters, and four out of five users will click away if loading takes too long. In fact, research shows that 250ms will provide a competitive advantage to the fastest of two competing solutions.

In 2007, Greg Linden, who previously worked at Amazon, stated that through A/B testing, he tried delaying a retail website page loading time in increments of 100ms, and found that even small delays would result in substantial and costly drops in revenue. With every 100ms increase in load time, sales dropped one percent. At the scale of Amazon, it’s clear that speed matters.

Content providers use caching techniques to get content to users faster. Cached content is served as if it is local to users, improving the delivery of static content.

A cache, is a hardware or software component that stores data so future requests for that data can be served faster; the data stored in a cache might be the result of an earlier…