Database Sharding

Summary

Splitting a single large database into multiple smaller databases (shards), each holding a subset of the data — used when a single database server can no longer hold or serve all your data.

How to Learn This

1Design a sharding key for a hypothetical multi-tenant app, e.g. shard by customer ID.
2Learn why resharding an already-live system is one of the hardest operations in backend engineering.
3Understand sharding solves a different problem than replication — data volume, not just read throughput.

Database Replication

CAP Theorem

More topics in System Design

Scalability Basics Vertical vs Horizontal Scaling Load Balancing Database Replication CAP Theorem Microservices vs Monolith API Gateway Service Discovery Circuit Breaker Pattern Distributed Caching Consistent Hashing Rate Limiting Algorithms Designing a URL Shortener Designing a Rate Limiter

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