Sharding and partitioning

Partitioning splits data across machines. The shard key decides whether that scales smoothly or creates one very hot node.

What this lesson covers

• Choose a shard key that spreads load evenly
• Compare range, hash, and directory partitioning
• Plan for resharding before you need it

This lesson sits in Data at Scale, part of System Design Foundations. It assumes what came before it and leads directly into the next lesson in the module.