Read Replica
A copy of your database that handles read queries, reducing load on the primary database. Writes still go to the primary and replicate out.
What is Read Replica?
A copy of your database that handles read queries, reducing load on the primary database. Writes still go to the primary and replicate out.
Read Replica is a intermediate-level concept that sits in the Data Replication & Distribution area of system design. Engineers reach for it whenever they need to reason about real-world trade-offs in that space — not just for textbook correctness, but because real production systems at companies like Netflix, Amazon, and Google make these decisions every day.
If you want to go deeper than this definition — with diagrams, code, and a quiz to lock it in — work through the "Read Replica" lesson linked below. It walks through the why, the mechanism, the trade-offs, and how the giants actually use it in production.
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See also
Related glossary terms you might want to look up next.
Replication
Keeping copies of the same data on multiple servers. Improves read performance and provides fault tolerance if one server goes down.
Leader Election
The process of choosing one node in a cluster to coordinate actions. If the leader fails, a new one is elected. Used by Kafka, ZooKeeper, and etcd.
Database
An organized collection of data that can be easily accessed, managed, and updated. The backbone of almost every application.