Scalability Architecture Framework

Scalability design fails when it's treated as "add more servers when things slow down." Horizontal scaling only works for stateless components; stateful components (databases, session storage, in-process caches) require specific strategies to scale. Adding more application servers doesn't help when the bottleneck is a single-threaded database write path. Every component in the system has a different scaling ceiling and a different scaling strategy, and the architecture must account for all of them.

The Scalability Architecture Framework identifies the bottleneck chain at each traffic tier, selects the right scaling strategy per component, and designs the system to reach 10× and 100× traffic without architectural redesign.