When it comes to scaling, we might need to think about:

• data storage, if we store more and more data and it becomes expensive or slow working with them
• fast INSERTs and UPDATES for write-heavy workloads
• making SELECT queries faster because of their complexity or because they need to query huge amounts of data
• concurrency if we have many clients interacting with the database

In this article, I will present some basic ideas and starting points on scaling traditional SQL databases.