# Scaling

Horizontal scaling is adding more machines to deal with increasing requirements. These machines handle requests in parallel to improve user experience.

Vertical scaling is replacing the current machines with more advanced machines to improve throughput and hence response time. The techniques are used in conjunction in real world systems.

# Horizontal vs. Vertical Scaling

Horizontal	Vertical
Many Servers	Huge Server
Load Balancing Required	N\A
Resilient	Single Port failure
Network Calls(RPC)-> transactions among servers	Inter-Process Communication	Data Inconsistency	Consistent
Scales well	Hardware limit