Load Balancing

Load balancing is the entry point to distributed systems thinking. Master it by understanding: (1) the problem it solves (single server limits), (2) the algorithms from simple to sophisticated, (3) the OSI layer distinction, (4) real tools you'll use in practice. What is Load Balancing? Imagine a restaurant with only one waiter serving 100 tables. Chaos, right? Now imagine 5 waiters, each handling 20 tables — smooth and efficient. That's load balancing. Load balancing distributes incoming network traffic across multiple servers to ensure no single server bears too much demand. This increases availability, reliability, and performance. Why It Matters Without it: One server handles everything → crashes under load With it: Traffic spread across servers → better performance, no single point of failure Real-World Example Netflix handles 250million subscribers. When you click Play, a load balancer decides which of Netflix's thousands of servers should stream your video based on server health, your location, and current load. Key Takeaway Load balancing is the first thing you add when a single server can't handle the traffic. It's the foundation of every scalable system. Java Implementation — Round Robin Load Balancer Python Implementation JavaScript/TypeScript Implementation