What is the main task of a load balancer and why is it used in distributed systems?

A load balancer distributes incoming traffic or requests across multiple servers or services to ensure even load distribution and improve system fault tolerance.

In distributed systems, it is used for:

• Increasing performance through parallel request processing
• Ensuring availability: if one server fails, the load balancer redirects traffic to others
• Scalability: allows easy addition of new servers without changing the client side

Example: a web application with multiple server instances behind a load balancer that directs requests based on a round-robin algorithm or current load.