Foundations of Scalable Systems

Chapter 2. Distributed Systems Architectures: An Introduction

In this chapter, I’ll broadly cover some of the fundamental approaches to scaling a software system. You can regard this as a 30,000-foot view of the content that is covered in Part II, Part III, and Part IV of this book. I’ll take you on a tour of the main architectural approaches used for scaling a system, and give pointers to later chapters where these issues are dealt with in depth. You can think of this as an overview of why we need these architectural tactics, with the remainder of the book explaining the how.

The type of systems this book is oriented toward are the internet-facing systems we all utilize every day. I’ll let you name your favorite. These systems accept requests from users through web and mobile interfaces, store and retrieve data based on user requests or events (e.g., a GPS-based system), and have some intelligent features such as providing recommendations or notifications based on previous user interactions.

I’ll start with a simple system design and show how it can be scaled. In the process, I’ll introduce several concepts that will be covered in much more detail later in this book. This chapter just gives a broad overview of these concepts and how they aid in scalability—truly a whirlwind tour!

Basic System Architecture

Virtually all massive-scale systems start off small and grow due to their success. It’s common, and sensible, to start with a development framework such as Ruby on Rails, Django, ...