10 - Programming for Scalability

Abstract

Scalability problems generally start appearing once a product has rolled out into full-scale production. The goal of a scalable system is that it must be available for use at all times and remain highly responsive regardless of how many people use the system. Scalability, with respect to software architectures, has also come to mean extensibility and modularity. This simply means that when a software system needs to scale upward in complexity, it does not need to be overhauled with each addition. At this stage in the life cycle, making modifications to the software becomes a logistical nightmare. Any changes to the software will necessarily have to be backward compatible with older versions of the product. Many software packages now include an autoupdater that accommodates post deployment updates; however, the best solution is to address scalability issues at the design phase, rather than ending up with a dozen versions of a product and the server downtime caused by implementing updates.