Database Replication Simulator — Interactive System Design Lab

Observe how a primary database replicates writes to replicas, experience replication lag under write pressure, and trigger a failover to see how replicas promote to leader. Essential for understanding read replicas and high availability.

Watch leader-follower replication lag and failover happen live.

This free interactive simulation runs directly in your browser — no account needed. Adjust the parameters and watch how the system responds in real time.

Concepts covered

• database replication
• leader follower
• replication lag
• failover
• high availability
• read replica

Read the guide

• Databases: SQL vs NoSQL — The heart of your architecture. Choosing the wrong database is the most expensive mistake you can make. Learn the 5 families of databases and when to use them.
• Consistency & Availability — The eternal trade-off. Learn why you can't have it all (CAP), how to handle the 99% of time when things ARE working (PACELC), and how to tune your truth.