Database Sharding and Read Replicas

Your database is the bottleneck. You have optimized queries, added indexes, implemented caching, and upgraded to a bigger server. But your application is still hitting the limits of a single database. Now what?

Read replicas and sharding are the tools for scaling your database beyond a single server. Read replicas are straightforward and should be your first move. Sharding is powerful but introduces complexity that can haunt your team for years. This lesson covers both, with a clear emphasis on when each is appropriate.

Read Replicas — The First Move

A read replica is a copy of your primary database that stays in sync through replication. Reads are distributed across replicas while writes go to the primary.

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