When working with Nginx and PHP-FPM, a common frustration occurs when editing php.ini settings like post_max_size and upload_max_filesize - the changes simply don't appear in phpinfo() output. Here's what's really happening:

# This shows the CLI PHP configuration
php -i | grep "post_max"
post_max_size => 20M => 20M

# While phpinfo() shows FPM configuration

PHP maintains separate configurations for different SAPI (Server API) modes:

• CLI: /etc/php5/cli/php.ini
• FPM: /etc/php5/fpm/php.ini
• Additional .ini files: Loaded from /etc/php5/fpm/conf.d/

Here's the step-by-step approach to ensure your changes take effect:

# 1. Edit the correct php.ini
sudo nano /etc/php5/fpm/php.ini

# 2. Modify these values:
post_max_size = 20M
upload_max_filesize = 18M

# 3. Check for overrides in conf.d
grep -r "post_max_size" /etc/php5/fpm/conf.d/

# 4. Restart services properly
sudo service php5-fpm restart
sudo service nginx restart

# 5. Verify with both methods
php -i | grep "post_max_size"
# And check phpinfo() in browser

Case 1: Changes made to CLI php.ini instead of FPM

Solution: Always modify /etc/php5/fpm/php.ini for web applications

Case 2: PHP-FPM not properly restarted

Solution: Use sudo service php5-fpm restart instead of reload

Case 3: Nginx fastcgi cache interfering

Solution: Clear Nginx cache if configured:

sudo rm -rf /var/run/nginx-cache/*
sudo service nginx reload

Create a test script to verify active configuration:

<?php
// config_test.php
header('Content-Type: text/plain');
echo "post_max_size: ".ini_get('post_max_size')."\n";
echo "upload_max_filesize: ".ini_get('upload_max_filesize')."\n";
?>

Run it both via CLI and web:

php config_test.php
curl http://localhost/config_test.php

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When working with Nginx + PHP-FPM setups, a common frustration occurs when editing php.ini parameters like:

post_max_size = 20M
upload_max_filesize = 18M

only to find phpinfo() still showing default 8M values after service restarts. The root cause lies in PHP's dual configuration system.

Key diagnostic commands reveal the conflict:

# CLI shows one config path
php -i | grep "Configuration File"

# While phpinfo() shows another
php -r "phpinfo();" | grep "php.ini"

This happens because:

• /etc/php5/cli/php.ini controls command-line PHP
• /etc/php5/fpm/php.ini governs PHP-FPM processes

To properly apply changes:

# 1. Edit the correct file
sudo nano /etc/php5/fpm/php.ini

# 2. Modify both directives
upload_max_filesize = 20M
post_max_size = 22M

# 3. Full service restart sequence
sudo service php5-fpm restart
sudo service nginx reload

Scan for overriding settings in:

/etc/php5/fpm/conf.d/*.ini
/etc/php5/fpm/pool.d/*.conf

Example pool override:

; /etc/php5/fpm/pool.d/www.conf
php_admin_value[post_max_size] = 8M
php_admin_value[upload_max_filesize] = 8M

Verify changes through multiple methods:

# Method 1: CLI check
php -r "echo ini_get('upload_max_filesize');"

# Method 2: Create test.php
<?php 
phpinfo(INFO_MODULES); 
?>

# Method 3: Direct FPM query
sudo php5-fpm -i | grep max_filesize

Remember that Nginx itself doesn't cache PHP configurations - this is purely a PHP-FPM service configuration matter.