Article on Scalability

Christopher Smith — Thu, 07 Dec 2006 18:34:00 +0000

Ran in to this nice little article from an eBay guy on scalability. I like a lot of the points raised, and it takes me back to my days as a consultant, particularly the first part where you ask questions like “4X more scalable in what way?”

In fact, in a lot of ways if someone says “4x more scalable” you generally know they are full of it. What they generally mean is “increased capacity 4x” (which leads to the follow up question about what kind of capacity was actually increased), but since they aren’t using those words, you have to think they are playing buzzword bingo, which is never a good sign.

Occasionally they may actually mean 4x more scalable, but generally changes of scalability are spoken about in big O notation, but it is possible that you might improve scalability by modifying a constant factor. Not as impressive but it can still save you a ton of money.

My one critique of this article is that it gets it’s terms wrong. It’s bad enough that the industry made up a term like “scalability”, but when we extend it to mean other things it makes it worse. The article describes “TPS per system” as one form of scalability improvement. I’m sorry, that’s improving efficiency. I’ll agree people often say “scalability” when they mean “efficiency”, but there is no need to compound the problem by saying so oneself.

In general, this article is more focused on capacity than scalability (which is why working on efficiency helps to improve things). Capacity is often the more pressing concern, but to a large degree an architecture design with an eye towards scalability will help you to worry a lot less about capacity issues.

Xblog: Article on Scalability

Article on Scalability