Designing for Scalability

Summary

Building systems that can grow to handle increased load — horizontal scaling (more instances) is generally preferred over vertical scaling (bigger instances) for its higher ceiling and better fault tolerance.

• 1Identify the bottleneck in a hypothetical architecture that would break first under 10x traffic.
• 2Learn why horizontal scaling requires stateless application design (no local session state).
• 3Practice designing a scaling plan for a hypothetical system as its user base grows.