What is database sharding and how does it work?

This post explains the concept of database sharding as a strategy for scaling out relational databases by partitioning data across multiple servers. It details the core components of sharding: choosing a sharding scheme (hash-based, range-based, directory-based), organizing infrastructure, creating a routing layer (often in the application layer), and planning/executing the migration. It also introduces Vitess as a mature open-source sharding framework for MySQL.