Load Balancer: The Traffic Cop of High Scale Systems (L4 vs L7)

Round Robin, Least Connections, IP Hash explained. The difference between L4 (Layer 4) and L7 (Layer 7) load balancing, and how to configure Nginx as a Reverse Proxy.

June 2, 2025

Codemapo

·May 25, 2025

Clean Architecture: The Dependency Rule and Separation of Concerns

A deep dive into Robert C. Martin's Clean Architecture. Learn how to decouple your business logic from frameworks, databases, and UI using Entities, Use Cases, and the Dependency Rule. Includes Screaming Architecture and Testing strategies.

#Software Architecture#Clean Code#Design Patterns#Backend

Clean Architecture: The Dependency Rule and Separation of Concerns

Computer Science·May 22, 2025

Keep-Alive: Don't hang up yet

Establishing TCP connection is expensive. Reuse it for multiple requests.

#CS#Web#HTTP#Optimization

Computer Science·May 18, 2025

WebSocket: Escape from Refresh Hell

HTTP is Walkie-Talkie (Over). WebSocket is Phone (Hello). The secret tech behind Chat and Stock Charts.

#CS#Web#WebSocket#Network

Computer Science·May 5, 2025

MAC Address: Physical ID Card

IP addresses change like home addresses. MAC addresses are like DNA or Fingerprints. Burned into hardware.

#CS#Network#Hardware

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11. Summary: What I Learned from Load Balancers

The core insights I gained from load balancers:

Scaling out is easy, distributing traffic is hard. Without load balancers, scale-out is meaningless.
L4 vs L7 is a "performance vs features" tradeoff. L7 isn't always better.
Avoid Sticky Sessions, embrace Stateless Architecture. Sessions belong in external stores like Redis.
Without Health Checks and Connection Draining, zero-downtime deployment is impossible.
Load balancers can die too. Eliminate SPOF by making load balancers redundant.

One-line summary: "Load balancers aren't just traffic distribution tools. They're core components of high-availability systems."