How to scale a web service?

AKF scale cube visualizes the scaling process into three dimensions…

1. ==Horizontal Duplication== and Cloning (X-Axis). Having a farm of identical and preferably stateless instances behind a load balancer or reverse proxy. Therefore, every request can be served by any of those hosts and there will be no single point of failure.
2. ==Functional Decomposition== and Segmentation - Microservices (Y-Axis). e.g. auth service, user profile service, photo service, etc
3. ==Horizontal Data Partitioning== - Shards (Z-Axis). Replicate the whole stack to different “pods”. Each pod can target a specific large group of users. For example, Uber had China and US data centers. Each datacenter might have different “pods” for different regions.

Want an example? Go to see how Facebook scale its social graph data store.