An introduction to application scaling

Scalability can be described as the capability of a system to grow and adapt to ever-changing conditions. Scalability is not limited to pure technical growth; it is also dependent on the growth of a business and the organization behind it.

If you are building the next "unicorn startup" and you expect your product to rapidly reach millions of users worldwide, you will face serious scalability challenges. How is your application going to sustain ever-increasing demand? Is the system going to get slower over time or crash often? How can you store high volumes of data and keep I/O under control? As you hire more people, how can you organize the different teams effectively and make them able to work autonomously, without contention across the different parts of the codebase?

Even if you are not working on a high-scale project, that doesn't mean that you will be free from scalability concerns. You will just face different...