Showing posts from September 22, 2007

What is scalability ?

When asked what they mean by scalability, a lot of people talk about improving performance, about implementing HA , or even talk about a particular technology or protocol. Unfortunately, scalability is none of that. Don't get me wrong. You still need to know all about speed, performance, HA technology, application platform, network, etc. But that is not the definition of scalability. Scalability, simply, is about doing what you do in a bigger way. Scaling a web application is all about allowing more people to use your application. If you can't figure out how to improve performance while scaling out, its okay. And as long as you can scale to handle larger number of users its ok to have multiple single points of failures as well. There are two key primary ways of scaling web applications which is in practice today. " Vertical Scalability " - Adding resource within the same logical unit to increase capacity. An example of this would be to add CPUs to an existing serve