A busy website rarely runs on one server. That sounds simple, but once hundreds or thousands of requests arrive together, sending everything to one machine gets messy fast. Load balancing keeps traffic moving by deciding which server should handle each request.

The method used for that decision matters. Some methods are very simple. Others look at what the servers are doing right now and make a choice based on that information.

Round Robin Load Balancing

Round robin is probably the easiest method to understand. Imagine three servers sitting behind a load balancer. The first request goes to Server A. The next goes to Server B. Then Server C. After that, the cycle starts again.

It works well when the servers have roughly the same capacity and requests take about the same amount of work. Because the traffic gets spread evenly in a predictable pattern, it’s easy to configure and doesn’t need much monitoring.

Least Connections

Least connections takes a more practical approach. The load balancer checks how many active connections each server currently has and sends a new request toward the server carrying the lighter load.

Why It Fits Busy Applications

This method feels smarter because it reacts to what’s happening right now. And that’s useful when traffic isn’t evenly spread. A server handling fewer connections gets some breathing room before the next wave arrives.

Still, connection count isn’t the whole story. One connection might barely use resources while another could keep a server busy for several seconds.

IP Hash

IP hash uses the user’s IP address to decide where traffic should go. The load balancer runs that address through a hashing process and uses the result to select a server.

The useful part is consistency. A user from the same IP will usually keep reaching the same server, which can be handy for applications that rely on session information stored locally.

There is a downside. If many users come through the same network, such as an office or mobile carrier, traffic can become uneven. One server gets crowded while another is sitting there doing almost nothing.

Weighted Load Balancing

Weighted methods are useful when your servers aren’t equally powerful. Give a stronger server a higher weight, and it receives more traffic. A smaller machine gets less.

• Server A has twice the weight, so it handles more requests without pretending every machine is identical.

• An older server gets a lighter share, which is much better than throwing the same traffic at everything.

Least Response Time

Least response time looks at how quickly servers are responding and directs new requests toward the faster option. This is especially useful when server performance changes throughout the day.

A server that’s technically available might still be struggling. Response time exposes that difference.

The right method depends on your setup. Round robin keeps things simple. Least connections reacts to active traffic. IP hash focuses on consistency. Weighted balancing handles different server capacities. Response-time methods pay closer attention to performance.