What methods can be used to implement horizontal scaling of a system?

Horizontal scaling of a system in Go (and generally) can be implemented by:

1. Adding new instances of the service — running multiple copies of the application on different servers or containers.
2. Load balancing — using load balancers (e.g., Nginx, HAProxy) to distribute requests among instances.
3. Data sharding — dividing the database or storage into parts, so different servers handle different data segments.
4. Using distributed queues and caching — for synchronization and speeding up request processing.

In Go, it is easy to run multiple instances of a service and use ready solutions for load balancing and distribution.