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Web Servers Comparison

Jun 19, 2025

Overview

This lecture compares Apache HTTP Server, Microsoft IIS, and NGINX, focusing on their core differences, strengths, weaknesses, and common use cases for web hosting.

Core Differences Between Web Servers

  • Apache uses a process-based model; each request spawns a new process or thread, impacting scalability under heavy load.
  • IIS and NGINX use event-driven models, enabling efficient asynchronous handling of many concurrent connections.
  • Apache runs on Unix, Linux, Windows, and macOS; IIS runs only on Windows; NGINX supports Unix-like OS and Windows.
  • Apache configuration uses a complex text-based system; IIS provides a graphical UI; NGINX uses simple, memory-efficient text config files.
  • Apache has the largest module ecosystem; IIS modules are fewer; NGINX supports modules but its ecosystem is smaller than Apache's.
  • Apache values stability and legacy support over peak performance; NGINX excels at high-load performance and resource efficiency; IIS is optimized for Windows integration.

Open Source vs Commercial Model

  • Apache is fully open-source under the Apache License.
  • IIS is proprietary, included with Windows Server, and requires a license for full features.
  • NGINX is available as both open source (with essential features) and commercial (with advanced features and support).

Community Insights and Use Cases

  • Many developers prefer NGINX for its lightweight, flexible, and easy-to-configure nature.
  • NGINX is recommended for high-performance, static content, and horizontal scaling with distributed architecture.
  • Apache is valued for its documentation, intuitive setup, and reliability.
  • IIS is favored in environments heavily using Microsoft technologies.
  • Automation tools like Ansible can streamline deployment and configuration, especially for large numbers of servers.

Pros and Cons Summary

  • Apache Pros: Most widely used, stable, extensive modules, robust, mature, SSL support.
  • IIS Pros: Best with .NET, easy Azure integration, shipped with Windows, simple GUI.
  • NGINX Pros: High performance, open source, easy setup, scalability, load balancing, reverse proxy, lightweight.
  • Apache Cons: Can be hard to set up for beginners.
  • IIS Cons: Can be hard to set up, expensive, restrictive.
  • NGINX Cons: Advanced features may require a commercial subscription.

Key Terms & Definitions

  • Web Server — Software that handles HTTP requests and serves web content.
  • Process-based Model — Each request handled by a separate process or thread.
  • Event-driven Model — Asynchronous handling of multiple requests with fewer threads.
  • Module — Add-on that extends web server functionality.
  • Reverse Proxy — Server that forwards client requests to other servers.
  • PHP-FPM — FastCGI Process Manager for handling PHP requests efficiently.

Action Items / Next Steps

  • Review characteristics of Apache, IIS, and NGINX for your environment.
  • Evaluate configuration and scalability needs before choosing a web server.
  • Explore documentation for setup and automation with tools like Ansible or Docker.