Replication and read scaling

Replicas give you read capacity and failover. They also give you a window where a follower answers with data that is slightly out of date.

What this lesson covers

• Distinguish synchronous from asynchronous replication
• Route reads to replicas without breaking read-your-writes
• Plan and rehearse failover

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.