What is PHP-FPM? A Comprehensive Guide to Optimize Your Website

 What is PHP-FPM? This is a question that many developers and system administrators often ask when looking for solutions to optimize website performance. A deep understanding of PHP-FPM can play a vital role in improving page load speed, scalability, and resource management on web servers. In this article, we will provide an overview of PHP-FPM, how it works, its configuration and its pros and cons, and how to deploy it on Docker.

What is PHP-FPM?

PHP-FPM (FastCGI Process Manager) is a software that processes PHP requests faster and more efficiently than traditional methods such as PHP-CGI. It is specifically designed to handle high-traffic PHP applications, providing a flexible and powerful approach to managing PHP versions and processes.

What is PHP-FPM? A Comprehensive Guide to Optimize Your Website Picture 1

What is PHP-FPM?

How does PHP-FPM work?

Here's how PHP-FPM works:

1. User sends request: When a user accesses a website through a browser, a request is sent to the web server.
2. Web server handles the request: The web server receives the request and determines if it is a PHP file. If so, it passes the request to PHP-FPM via the FastCGI protocol.
3. PHP-FPM receives the request: PHP-FPM receives the request and distributes it to one of the worker processes in the configured pool.
4. Execute PHP code: Worker process executes PHP code and produces results.
5. Return results: The results from the worker process are sent back to PHP-FPM, which then returns the results to the web server.
6. Returning results to the user: Finally, the web server sends the results back to the user in HTML form.

Common PHP-FPM configuration parameters

PHP-FPM configuration can have a major impact on the performance and scalability of your application. Here are some common configuration parameters you should pay attention to.

pm.max_children

This is the maximum number of worker processes that PHP-FPM can initiate simultaneously. This parameter is important because it directly affects the server's ability to serve requests. It depends on the server's resources, but is usually calculated based on the total available RAM and the average RAM usage of each process.

pm.start_servers

The number of worker processes that are initialized when PHP-FPM starts. This ensures that there are enough processes available to handle requests from the start. This value should be set based on the expected server load.

pm.min_spare_servers

A minimum number of idle worker processes is maintained to be ready to serve new requests. If this number falls below a certain level, PHP-FPM will automatically create more processes. This parameter should be adjusted to ensure that the server always has enough idle processes.

pm.max_spare_servers

The maximum number of idle worker processes that PHP-FPM can maintain. If this value is exceeded, some processes will be killed to save resources. Similar to pm.min_spare_servers, this value should be adjusted according to the server load.

pm.max_requests

The maximum number of requests that each worker process can handle before it is restarted. This parameter helps prevent memory leaks and improves application stability. This value can be set from 500 to 1000 depending on the specific application.

pm.status_path

A path to monitor the status of PHP-FPM, allowing administrators to check information about the number of pending requests and the status of worker processes.

Advantages of using PHP-FPM

Better performance

With the ability to handle multiple requests concurrently, PHP-FPM significantly improves the response time of PHP applications. This is especially important for high-traffic websites where access speed is vital.

Efficient resource management

Thanks to its process management capabilities and flexible configuration parameters, PHP-FPM optimizes the use of system resources, from CPU to memory. This not only saves costs but also increases the stability of the application.

Easy to configure and expand

With a variety of configuration options, PHP-FPM allows users to easily adjust to suit the actual needs of the application. You can flexibly change the parameters to best meet the user's requirements.

Some limitations still exist

Need specialized knowledge

Configuring PHP-FPM can be difficult for beginners. If you don't understand the parameters and how it works, you can cause your application to suffer performance losses.

Compatibility

Some older applications or plugins sometimes do not integrate well with PHP-FPM. This can cause unexpected problems and require users to have skills to fix.

Complex management

If you run multiple PHP applications on the same server, managing multiple PHP-FPM configurations can become complex and error-prone. Incorrect setup can reduce overall system performance.

How is PHP-FPM different from PHP-CGI?

How it works

Each PHP request from the web server will initiate a new process. This means that when there are many concurrent requests, the server will spend a lot of resources restarting PHP processes, resulting in poor performance.

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How is PHP-FPM different from PHP-CGI?

PHP-FPM maintains a pool of reusable PHP processes. When a request is made, one of these processes is assigned to run, reducing startup time and increasing concurrency.

About performance

Because PHP-CGI must initiate a new process for each request, PHP-CGI often has lower performance, especially in high traffic environments.

By using a worker pool, PHP-FPM allows multiple requests to be processed concurrently without sacrificing performance. This saves resources and improves the response speed of web applications.

On resource management capabilities

PHP-CGI's management capabilities are inefficient because it has to create a new process for each request, resulting in suboptimal CPU and memory usage.

Meanwhile PHP-FPM: Allows better resource management thanks to the reuse of processes in the pool. This not only saves resources but also helps reduce the load on the server.

About security

Although CGI can operate independently of the web server, spawning a new process for each request can also lead to security issues if not configured properly.

PHP-FPM on the other hand Provides better security due to the processes being isolated and more tightly managed. Furthermore, it allows easier logging and tracking of process activities.

Is PHP-FPM compatible with both Nginx and Apache web servers?

Compatible with Nginx

Nginx cannot process PHP scripts directly, so it needs to use PHP-FPM to handle PHP requests. Nginx will forward requests to PHP-FPM via the FastCGI protocol. Typical configuration includes setting fastcgi_pass to specify the address and port that PHP-FPM listens on.

Nginx is generally considered faster than Apache at serving static content and is better able to handle multiple concurrent connections. When combined with PHP-FPM, Nginx can optimize performance for large web applications.

Compatible with Apache

Similar to Nginx, Apache can also use PHP-FPM to handle PHP requests. In this case, Apache will send requests to PHP-FPM through the FastCGI interface. Apache version 2.4 and above are configured to support PHP-FPM more efficiently.

While both servers can work well with PHP-FPM, Apache can provide better performance for applications with heavy dynamic content, while Nginx excels at serving static content.

How to deploy PHP-FPM on Docker

To deploy PHP-FPM on Docker, you can follow these steps:

Step 1: Create project folder structure

Create a project folder with the following structure:

Where, index.php is the PHP file you want to run.

Step 2: Create Dockerfile for PHP-FPM

Create a Dockerfile file in the project directory with the following content:

FROM php:7.4-fpm

# Install the necessary extensions

RUN docker-php-ext-install pdo pdo_mysql

# Copy source code into container

COPY app/ /var/www/html/

This file uses the official PHP-FPM image and installs the necessary extensions for PDO.

Step 3: Create docker-compose.yml file

Create a docker-compose.yml file in the same directory with the following content:

In this file, we define two services: one for PHP-FPM and one for Nginx. Nginx will serve HTTP requests and forward them to PHP-FPM.

Step 4: Create Nginx configuration

Create an nginx.conf file in the project directory with the following content:

This configuration specifies how Nginx handles PHP files by forwarding them to the PHP-FPM service.

Step 5: Start the application

Run the following command in the project directory to start the services:

docker-compose up --build

Once the startup process is complete, you can access your application at http://localhost.

docker-compose up --build

Conclude

PHP-FPM is a powerful tool for optimizing the performance of PHP web applications. With its outstanding advantages in process management, scalability and performance, PHP-FPM has become the first choice for many programmers and system administrators.

David Pac

Update 12 February 2025