The Four Quadrants: Every Possible Database Architecture

Let's map out every possible combination of partitioning and sharding. There are exactly four scenarios:

Quadrant 1: No Partitioning + No Sharding

• One database server, all data together
• Classic monolith architecture
• Perfect for small applications
• Simple but limited

Quadrant 2: Partitioning + No Sharding

• One database server, but data split into multiple databases
• Example: CREATE DATABASE auth; CREATE DATABASE orders;
• Future-proofing without extra cost
• Preparation for scaling

Quadrant 3: Partitioning + Sharding

• Multiple database servers, each with different data
• True microservices architecture
• Maximum scalability and isolation
• Complex but powerful

Quadrant 4: No Partitioning + Sharding

• Multiple database servers with identical data
• This is Read Replicas!
• Same data everywhere, different servers
• Perfect for scaling reads

Key Insight: "Every database architecture fits into one of these four quadrants - understanding this map helps you navigate any scaling decision."