Choosing the Right Load Balancing Algorithm: Round Robin, Weighted, Least Connection, and More

Round Robin

This method distributes incoming requests cyclically across all servers in the pool, assuming they have similar capacity. It works well when servers have comparable performance, but can overload weaker servers if capacities differ.

Weighted Round Robin

This algorithm extends simple round robin by assigning a weight to each server based on its processing capability. A server with higher weight receives more consecutive requests before moving to the next server.

Least Connection

This method routes each new request to the server with the fewest active connections, addressing cases where request duration varies and simple round robin would cause overload on slower servers.

Least Connection Slow Start Time

When a newly added server joins the pool, a slow‑start period limits its connection count, allowing it to ramp up gradually and avoid immediate overload.

Weighted Least Connection

Combines server weights with current connection counts, providing a balanced distribution when servers have different capacities.

Agent Based Adaptive Balancing

The load balancer periodically collects a load metric (0‑99) from each server and adjusts weights dynamically. If load is low, it may fall back to weighted round robin; if high, it uses the adaptive algorithm.

Fixed Weighted

Highest weight is used only when all other servers have low weights; if the top server fails, the next highest takes over, based on configured priority.

Weighted Response

Weights are calculated from server health‑check response times, recomputed roughly every 15 seconds, assuming faster responses indicate higher capacity.

Source IP Hash

Requests are mapped to servers based on a hash of the client’s IP address, ensuring the same client consistently reaches the same server, though it may cause imbalance.