How to Enable PHP OPcache on Ubuntu 22.04 for Better Performance

A practical guide for Apache and Nginx with PHP-FPM

PHP applications can become slow when the server has to repeatedly parse and compile PHP scripts for every request.

This is where PHP OPcache helps.

OPcache improves PHP performance by storing precompiled PHP bytecode in memory. Instead of loading and compiling PHP files again and again, PHP can reuse the cached bytecode.

For production systems such as Laravel, WordPress, GLPI, or custom PHP applications, enabling OPcache is one of the easiest ways to improve response time and reduce CPU usage.

This guide explains how to install and enable OPcache on Ubuntu 22.04 for both:

Apache + PHP
Nginx + PHP-FPM

Prerequisites

Before starting, make sure you have:

Ubuntu 22.04 server
Root or sudo user access
PHP installed or ready to install
Apache or Nginx web server
SSH access to the server

Step 1: Update the Server

First, connect to your server using SSH.

ssh root@IP_Address -p Port_number

Replace:

IP_Address     = your server IP address
Port_number    = your SSH port

If you are using a non-root sudo user:

ssh username@IP_Address -p Port_number

After login, update the server packages:

sudo apt update -y
sudo apt upgrade -y

This ensures your system has the latest security and package updates.

Step 2: Check Current PHP Version

Check the installed PHP version:

php -v

Example output:

PHP 8.1.2-1ubuntu2.13 (cli)
Zend Engine v4.1.2
with Zend OPcache v8.1.2

If you see with Zend OPcache, OPcache is already installed, but it may still need configuration.

Option A: Enable OPcache for Apache

Use this section if your PHP application runs with Apache.

Install Apache, PHP, and OPcache

Install Apache, PHP, OPcache, and common PHP extensions:

sudo apt install apache2 libapache2-mod-php php php-cli php-opcache php-mysql php-zip php-gd php-mbstring php-curl php-xml -y

After installation, check PHP version again:

php -v

You should see OPcache included in the output.

Configure OPcache for Apache

Open the Apache PHP configuration file.

For PHP 8.1:

sudo nano /etc/php/8.1/apache2/php.ini

Find and update the following settings:

opcache.enable=1
opcache.memory_consumption=128
opcache.max_accelerated_files=10000
opcache.revalidate_freq=200

Recommended production configuration:

opcache.enable=1
opcache.enable_cli=0
opcache.memory_consumption=128
opcache.interned_strings_buffer=16
opcache.max_accelerated_files=10000
opcache.revalidate_freq=60
opcache.validate_timestamps=1
opcache.save_comments=1
opcache.fast_shutdown=1

For Laravel or production systems where deployment is controlled, you may use:

opcache.validate_timestamps=0

However, if you set validate_timestamps=0, PHP will not automatically detect file changes. You must restart or reload PHP/Apache after every deployment.

For most general production servers, this is safer:

opcache.validate_timestamps=1
opcache.revalidate_freq=6

Restart Apache

Apply the changes:

sudo systemctl restart apache2

Check Apache status:

sudo systemctl status apache2

Option B: Enable OPcache for Nginx with PHP-FPM

Use this section if your PHP application runs with Nginx and PHP-FPM.

Install PHP-FPM and OPcache

Install PHP-FPM and OPcache:

sudo apt install php-fpm php-opcache -y

If your application needs common PHP extensions, install them too:

sudo apt install php-cli php-mysql php-zip php-gd php-mbstring php-curl php-xml -y

Check your PHP-FPM version:

ls /etc/php/

Example output:

8.1

Configure OPcache for PHP-FPM

Open the PHP-FPM php.ini file.

For PHP 8.1:

sudo nano /etc/php/8.1/fpm/php.ini

Update or add these settings:

opcache.enable=1
opcache.memory_consumption=128
opcache.max_accelerated_files=10000
opcache.revalidate_freq=60

Recommended production configuration:

opcache.enable=1
opcache.enable_cli=0
opcache.memory_consumption=128
opcache.interned_strings_buffer=16
opcache.max_accelerated_files=10000
opcache.revalidate_freq=60
opcache.validate_timestamps=1
opcache.save_comments=1
opcache.fast_shutdown=1

For high-traffic production systems with controlled deployment, you can consider:

opcache.validate_timestamps=0

But remember: after changing application code, you must restart PHP-FPM.

Restart PHP-FPM and Nginx

Apply the changes:

sudo systemctl restart php8.1-fpm
sudo systemctl restart nginx

Check service status:

sudo systemctl status php8.1-fpm
sudo systemctl status nginx

If you use another PHP version, replace php8.1-fpm with your installed version.

Example for PHP 8.3:

sudo systemctl restart php8.3-fpm

Step 3: Verify OPcache Is Enabled

Run:

php -i | grep opcache

You should see OPcache configuration output.

You can also check specifically:

php -i | grep "opcache.enable"

Example output:

opcache.enable => On => On

For PHP-FPM, CLI output may not always reflect the FPM configuration. To confirm from the web server side, create a temporary PHP info file.

echo "<?php phpinfo(); ?>" | sudo tee /var/www/html/info.php

Then open in browser:

http://your-server-ip/info.php

Search for:

Zend OPcache

After checking, remove the file immediately:

sudo rm /var/www/html/info.php

Do not leave phpinfo() files on production servers because they expose sensitive configuration details.

Step 4: Recommended OPcache Settings Explained

opcache.enable

opcache.enable=1

Enables OPcache.

opcache.memory_consumption

opcache.memory_consumption=128

Defines how much memory OPcache can use.

For small applications, 128MB is usually enough.

For large Laravel, GLPI, WordPress, or enterprise systems, you may increase it:

opcache.memory_consumption=256

opcache.max_accelerated_files

opcache.max_accelerated_files=10000

Defines how many PHP files can be cached.

For larger applications, use:

opcache.max_accelerated_files=20000

opcache.revalidate_freq

opcache.revalidate_freq=60

Defines how often PHP checks if files have changed.

A value of 60 means PHP checks for file changes every 60 seconds.

opcache.validate_timestamps

opcache.validate_timestamps=1

When enabled, PHP checks whether files have changed.

This is safer for most environments.

For maximum performance in controlled production deployments:

opcache.validate_timestamps=0

But with this setting, new code changes will not appear until PHP-FPM or Apache is restarted.

Step 5: OPcache Settings for Laravel Production

For Laravel production servers, you can use this configuration:

opcache.enable=1
opcache.enable_cli=0
opcache.memory_consumption=256
opcache.interned_strings_buffer=16
opcache.max_accelerated_files=20000
opcache.revalidate_freq=60
opcache.validate_timestamps=1
opcache.save_comments=1
opcache.fast_shutdown=1

If you have a proper deployment process, you may use:

opcache.validate_timestamps=0

Then after deployment, reload PHP-FPM:

sudo systemctl reload php8.1-fpm

or restart:

sudo systemctl restart php8.1-fpm

Also optimize Laravel:

php artisan config:cache
php artisan route:cache
php artisan view:cache
php artisan event:cache

Step 6: Check OPcache Memory Usage

You can check OPcache settings using:

php -i | grep opcache.memory_consumption

For deeper monitoring, you can install an OPcache status page, but be careful not to expose it publicly.

If OPcache memory becomes full, you may see performance drop because PHP cannot cache more files.

In that case, increase:

opcache.memory_consumption=256
opcache.max_accelerated_files=20000

Step 7: Common Issues

OPcache Installed but Not Enabled

Check:

php -m | grep Zend
php -i | grep opcache.enable

If needed, enable the module:

sudo phpenmod opcache

Then restart the service:

For Apache:

sudo systemctl restart apache2

For PHP-FPM:

sudo systemctl restart php8.1-fpm
sudo systemctl restart nginx

Wrong PHP Version Edited

If multiple PHP versions are installed, make sure you edit the correct file.

Check available versions:

ls /etc/php/

Apache PHP config:

/etc/php/8.1/apache2/php.ini

PHP-FPM config:

/etc/php/8.1/fpm/php.ini

CLI config:

/etc/php/8.1/cli/php.ini

For Nginx, usually edit the fpm file, not the apache2 file.

Code Changes Not Showing

If you set:

opcache.validate_timestamps=0

PHP will not automatically detect file changes.

Restart PHP-FPM or Apache after deployment.

For Nginx + PHP-FPM:

sudo systemctl restart php8.1-fpm

For Apache:

sudo systemctl restart apache2

OPcache Not Showing in Browser

If php -i shows OPcache but browser does not, you may be checking CLI PHP instead of web PHP.

Create a temporary phpinfo() file, check from browser, then remove it.

Production Checklist

Before finishing, verify:

PHP is installed
OPcache package is installed
Correct php.ini file is updated
opcache.enable=1
Web service restarted
PHP-FPM restarted if using Nginx
OPcache confirmed by php -i or phpinfo()
phpinfo() file removed
Laravel/application cache rebuilt if needed

Quick Commands Summary

Apache

sudo apt update -y
sudo apt install apache2 libapache2-mod-php php php-cli php-opcache -y

sudo nano /etc/php/8.1/apache2/php.ini

sudo systemctl restart apache2

php -i | grep opcache

Nginx + PHP-FPM

sudo apt update -y
sudo apt install nginx php-fpm php-opcache -y

sudo nano /etc/php/8.1/fpm/php.ini

sudo systemctl restart php8.1-fpm
sudo systemctl restart nginx

php -i | grep opcache

Final Thoughts

Enabling PHP OPcache is one of the simplest and most effective ways to improve PHP application performance.

It reduces repeated PHP compilation, lowers CPU usage, and improves response time for production applications.

For Apache, configure OPcache in:

/etc/php/8.1/apache2/php.ini

For Nginx with PHP-FPM, configure OPcache in:

/etc/php/8.1/fpm/php.ini

The key lesson is simple:

If you run PHP in production, OPcache should be enabled and tuned properly.