These PHP handlers represent fundamentally different approaches to executing PHP scripts:

• CGI (Common Gateway Interface): Spawns new process per request

  // Example CGI call
  GET /script.php HTTP/1.1
  Host: example.com
  → Spawns new PHP process → Returns output → Terminates

• FastCGI: Persistent process with socket communication

  // FastCGI process manager configuration (php-fpm.conf)
  pm = dynamic
  pm.max_children = 50
  pm.start_servers = 5
  pm.min_spare_servers = 2
  pm.max_spare_servers = 8

• mod_php: Apache module running within web server

  # Apache configuration for mod_php
  LoadModule php7_module modules/libphp7.so
  AddHandler php7-script .php

• suPHP: CGI wrapper with user isolation

  # suPHP configuration
  [global]
  logfile=/var/log/suphp.log
  webserver_user=www-data
  umask=0022

Sample benchmark results (requests/second) on identical hardware:

Handler	Static	DB Query	Complex App
CGI	23	9	5
FastCGI	1420	380	210
mod_php	1350	350	180
suPHP	35	15	8
PHP-FPM	1480	420	230

Consider these security aspects when choosing a handler:

// Dangerous example requiring proper isolation
<?php
file_put_contents('/etc/passwd', 'hacked');
?>

• mod_php: Runs as web server user (potential privilege issues)
• suPHP: Executes scripts under owner's permissions (better isolation)
• PHP-FPM: Supports chroot and user/group separation

Implementing PHP-FPM with Nginx:

# nginx configuration
location ~ \.php$ {
    fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
    fastcgi_index index.php;
    include fastcgi_params;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}

Enabling opcode caching with mod_php:

# php.ini for mod_php
opcache.enable=1
opcache.memory_consumption=128
opcache.max_accelerated_files=4000
opcache.validate_timestamps=60

When switching from mod_php to PHP-FPM:

1. Check for apache_get_modules() dependencies
2. Update .htaccess rules (some don't apply to FPM)
3. Verify file permissions (different user context)
4. Test session handling differences

For new deployments in 2023:

• High traffic: PHP-FPM + Nginx
• Shared hosting: suPHP or PHP-FPM with per-user pools
• Legacy systems: mod_php (when migration isn't feasible)
• Microservices: FastCGI with containerized PHP

Real-world case: WordPress on PHP-FPM showing 3x performance improvement over mod_php with the same hardware resources.

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When deploying PHP applications, the choice of execution handler significantly impacts performance, security, and resource management. Let's examine the technical implementations:

The original PHP execution method spawns a new process for each request:

#!/usr/bin/php-cgi

Pros:

• Simple isolation between requests
• Works with any web server

Cons:

• High process overhead
• No persistent connections

An optimized version of CGI that maintains persistent processes:

location ~ \.php$ {
    fastcgi_pass   127.0.0.1:9000;
    fastcgi_index  index.php;
    include        fastcgi_params;
}

Pros:

• Reduced process creation overhead
• Better performance than CGI

Cons:

• More complex configuration
• Requires separate process manager

PHP runs as an Apache module:

LoadModule php7_module modules/libphp7.so
AddHandler php7-script .php

Pros:

• Excellent performance for Apache
• Native integration with Apache features

Cons:

• Apache-only solution
• Runs with web server permissions

Secure PHP execution with per-user permissions:

suPHP_Engine on
suPHP_UserGroup user group

Pros:

• Improved security through user isolation
• Prevents shared hosting security issues

Cons:

• Performance overhead
• Complex permission management

The modern recommended approach for most deployments:

[www]
user = www-data
group = www-data
listen = /var/run/php/php7.4-fpm.sock
pm = dynamic
pm.max_children = 50
pm.start_servers = 5
pm.min_spare_servers = 5
pm.max_spare_servers = 35

Pros:

• Excellent performance and scalability
• Advanced process management
• Works with Nginx and Apache

Cons:

• More complex setup
• Requires separate configuration

Benchmark results (requests/second) on identical hardware:

Handler	Static	WordPress	Laravel
CGI	120	35	28
FastCGI	950	210	180
mod_php	1100	240	190
suPHP	400	95	80
PHP-FPM	1300	280	230

Choose CGI when:

• Maximum security isolation is required
• You need simple deployment

Choose FastCGI when:

• Running older systems
• Need better performance than CGI

Choose mod_php when:

• Running Apache-only environments
• Need best possible Apache integration

Choose suPHP when:

• Running shared hosting environments
• User isolation is critical

Choose PHP-FPM when:

• Performance is key requirement
• Using Nginx or modern Apache