GridFix Labs Reference Series | Cloud & Software-Defined
Load Balancing Algorithms
The Logic of Horizontal Scale
GridFix Technical Team Last Updated: January 31, 2026 11 min read Read
Verified by Engineering
In a Nutshell
As traffic grows beyond the capacity of a single server, we must distribute requests across a pool of resources. The Load Balancer (LB) is the traffic cop that makes this decision. This article analyzes common algorithms from simple Round Robin to advanced Least Connections and the complexities of session persistence.
The "Traffic Cop" Problem
The goal of load balancing is to maximize throughput, minimize response time, and ensure no single server is overwhelmed.
Health Checks: The Pulse of the Pool
An algorithm is useless if it sends traffic to a dead server. Load balancers perform periodic Health Checks.
L3/L4 Check: Can I ping the server? Is port 443 open?
L7 (Active) Check: Does the `/health` endpoint return a `200 OK`? This detects application-level hangs even if the network stack is up.
Session Persistence (Sticky Sessions)
Many legacy applications store user data in local server RAM. If a user's first request goes to Server A and their second goes to Server B, they are 'logged out.'
We solve this with Session Affinity (using cookies or IP hashing), though modern architecture prefers Stateless Services where session data is stored in a shared Redis cache.
Conclusion
Load balancing is the foundation of high availability. By choosing the right algorithm for your traffic pattern, you transform a fragile single point of failure into a resilient, scalable cluster.
