Definition

Load balancing is distributing incoming requests or tasks across multiple servers/resources to optimize performance and avoid overload.

Core concept

A load balancer (software/hardware) sits in front of servers and routes each new request based on an algorithm (round-robin, least-connections, etc.). This ensures no single server gets overwhelmed while others idle.

Use cases

Web servers behind an HA proxy; database replicas behind a proxy; microservices with many instances.

Trade-offs

Load balancers can become bottlenecks or single points of failure (mitigated by redundancy). Poor algorithms may lead to uneven distribution.

Example

An HAProxy or AWS ELB sends each client HTTP request to the least-loaded web server.

References

“Load balancing is the process of distributing a set of tasks over a set of resources… making processing more efficient”[[[40]](https://en.wikipedia.org/wiki/Load_balancing_(computing "Load balancing (computing) - Wikipedia").