Expert One-on-One™ C# Design and Development

Chapter 20. Considering Application Reliability Implications

Reliability is never noticed. If no one's paying any attention to your application (they just use it without thinking about it), it's probably because you've achieved that most desired of all application traits — reliability. Think about it for a moment. When you go home tonight and flip the switch for the lights, you probably won't think about it. In fact, you may not even remember flipping the switch. The only time you notice the electricity in your house is when the power is out — when the power has become unreliable. Otherwise, you pay no attention to it at all, and that's how things should be. Likewise, no one should notice your application — users should simply sit down and start using it. If you can achieve that state of nothingness, where the user doesn't even remember using the application, you've really done something, because it's quite likely that few developers will ever attain this status.

Reliability is also never complete. Consequently, you'll always have something to work on from a reliability perspective. The reason that people talk about five nines, or 99.999 percent, reliability is that you simply can't achieve the other 0.001 percent. What this means to you as a developer is that you can't afford to oversell the reliability of your application. No matter what you do, your application will fail at some point. Telling someone anything different will always land you in trouble.

This chapter emphasizes real-world ...