Re: What Is Scalability?

--- Brad Pauly <brad@robinsontech.com> wrote: > Good question! This has been on my mind some for a current project > and now I have thought about it even more. Hmm, I'm not sure how to > quote a blog. To paraphrase (hope you don't mind), Chris's > definition of something that scales well is when resources (in > general things that cost money) grow either linearly or > logarithmically as the number of users grows. I agree with this as > long as the slope of the linear graph is close to or less than 1. Yes, I considered adding an extra condition to the linear case that the rate of growth should be less than or equal to 1/1. I tries to keep things as simple as possible, however, so that my discussion didn't make matters worse. :-) > Some of the factors that I would consider for determining if a > technology will scale well for a web application are: it's ease of > use (how hard is it to develop in), general performance (it can't be > a complete dog, however, small discrepancies compared to similar > technologies are usually ok), and how well can you spread it out > (scalable web applications are often in a multi-server environment). I disagree about the performance part, but I feel like I am alone. As an example, take a train versus a sports car. The train is probably a lot slower, so it performs worse. However, the train scales much better than the sports car when you start talking about hauling weight. Tie a rail car to the sports car and see what happens. :-) So, I think scalability is relative to the performance of the solution. A long distance runner is more scalable than a sprinter, even though a sprinter probably runs faster. In some cases, I'm sure the faster solution also scales better, but I don't think this is necessarily the case. > Do others consider application design when talking about scalability? Absolutely, but only when looking at the complete solution. When people talk about whether something like PHP is scalable, I try to isolate programming languages in an "all else being equal" perspective. Anyway, thanks for your thoughts. Chris ===== My Blog http://shiflett.org/ HTTP Developer's Handbook http://httphandbook.org/ RAMP Training Courses http://www.nyphp.org/ramp