PHP-FPM vs nginx: What are the differences?

Introduction

PHP-FPM and nginx are both important components in web servers. Understanding their key differences can help in choosing the right setup for websites and applications.

1. Execution Model: PHP-FPM is a process manager for PHP which handles PHP script execution and management of workers. It communicates with the web server (like nginx) using FastCGI protocol. On the other hand, nginx is a high-performance web server and reverse proxy server that can also act as an HTTP cache. It can handle static content efficiently and can also forward dynamic requests to PHP-FPM.

2. Architecture: PHP-FPM follows a pool or worker model where multiple dedicated worker processes handle incoming PHP requests. Each worker process can handle multiple requests simultaneously using threads or processes. On the other hand, nginx uses an asynchronous and event-driven architecture where a single master process handles all incoming requests efficiently without blocking multiple connections.

3. Resource Handling: PHP-FPM primarily handles PHP scripting and processing, including database connections, session management, and application logic. It depends on the web server (like nginx) to handle static file requests efficiently. Nginx, on the other hand, excels at serving static files due to its efficient architecture. It can handle static content without the need to involve PHP-FPM for processing.

4. Load Balancing: PHP-FPM supports load balancing by using multiple worker processes. It can distribute requests across different PHP-FPM instances, ensuring efficient resource utilization and increased performance. Nginx also supports load balancing, but at a higher level. It can distribute requests to backend servers (including PHP-FPM instances) using various load balancing algorithms like round-robin, IP-hash, etc.

5. Caching: PHP-FPM does not provide built-in caching mechanisms. However, it can integrate with other caching solutions like Varnish or a Content Delivery Network (CDN) to improve performance. Nginx, on the other hand, includes a built-in caching module that can cache responses from dynamic requests. It can cache content in memory, on disk, or even on a distributed cache server like Redis.

6. Configuration and Extensibility: PHP-FPM configuration involves settings related to PHP execution, process management, and resource limits. It can be tweaked to achieve optimal performance based on specific application requirements. Nginx provides rich configuration options for customizing server behavior, handling server blocks, SSL/TLS settings, and more. It also supports various modules for additional functionality like URL rewriting, gzip compression, rate limiting, and more.

In summary, PHP-FPM is responsible for executing PHP scripts and managing worker processes, while nginx acts as a powerful web server, reverse proxy, and can handle static content efficiently. PHP-FPM excels at processing PHP requests, while nginx is effective at serving static files and load-balancing requests. Both technologies have their strengths and can be used together to achieve high-performance web applications.