This article explains what is meant by system scalability particularly when talking about large mission critical systems used by large enterprises. First we will explain why a system needs to be scalable and then we will explain exactly what we mean by scalability.
Why does a computer system need to scale?
Most business owners and managers are keen to see their business grow. As a natural consequence of this growth an increasing load will be put on the businesses IT systems. For example imagine that your business has been identified as the next big thing on the Internet and because of this more and more people are visiting your business website. Your IT staff need to make sure that your website can cope with the extra visitors and the possibility of even more visitors as your company becomes more popular. The way that they can do this in the short term is add extra servers that handle the increased web page requests from your visitors.? But as more and more visitors arrive at you website they will need to add even more servers. If your website has been designed well adding extra servers will handle the increased load. When this happens it is said tat your website or system is scalable. That is it scales without problems as your business grows. If it didn't scale as your business grows then an increased load will overload your servers and the website would be unavailable for long periods.
What exactly is scalability
So we can see that scalability is the ability of a system to grow gracefully without interruption over time as load increases. Scalability is a very important factor in large system design. n fact it one of the big three factors that must be taken into account when designing large system.
