Scaling systems

It's now time to take a slightly higher-level view of scalability. Once we have written code and deployed it, how can we scale it?

The book The Art of Scalability (http://theartofscalability.com/), describes a really useful, three-dimensional scalability model in the form of a scale cube:

Each of the axes represents a specific way in which an application can be augmented to enable scalability in the face of increased load/traffic. They are described in the next sections.

X-axis scaling

Scaling along the x-axis means running multiple copies (instances) of the application behind a load balancer. If there are n instances, then each handles 1/n of the load. This is the simplest way of increasing scalability...