Redis崩潰

I'm very serious about software reliability, and this is not just a good thing.
It is good in a sense, as I tend to work to ensure that the software I release is solid. At the same time I think I take this issue a bit too personally: I get upset if I receive a crash report that I can't investigate further for some reason, or that looks like almost impossible to me, or with an unhelpful stack trace.

Guess what? This is a bad attitude because to deliver bugs free software is simply impossible. We are used to think in terms of labels: "stable", "production ready", "beta quality". I think that these labels are actually pretty misleading if not put in the right perspective.

Software reliability is an incredibly complex mix of ingredients.

1) Precision of the specification or documentation itself. If you don't know how the software is supposed to behave, you have things that may be bugs or features. It depends on the point of view.
2) Amount of things not working accordingly to the specification, or causing a software crash. Let's call these just software "errors".
3) Percentage of errors that happen to be in the subset of the software that is actually used and stressed by most users.
4) Probability that the conditions needed for a given error to happen are met.

So what happens is that you code something, and this initial version will be as good as good and meticulous are you as a programmer, or as good is your team and organization if it is a larger software project involving many developers. But this initial version contains a number of errors anyway.

Then you and your users test, or simply use, this new code. All the errors that are likely to happen and to be recognized, because they live in the subset of the code that users hit the most, start to be discovered. Initially you discover a lot of issues in a short time, then every new bug takes more time to be found, probabilistically speaking, as it starts to be in the part of the code that is less stressed, or the conditions to make the error evident are unlikely to be met.

來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/301743/viewspace-750467/，如需轉載，請註明出處，否則將追究法律責任。