How to Install Opcache for Optimal PHP Performance on Linux

Ravi SaiveLast Updated: October 17, 2024 Read Time: 3 minsPHP 35 Comments

PHP (Hypertext Preprocessor) is a widely-used server-side scripting language known for its efficiency in web development. However, as web applications grow in complexity, performance optimization becomes crucial.

One of the most effective ways to enhance PHP performance is by using Opcache, which caches the compiled bytecode of PHP scripts, reducing the overhead of loading and parsing scripts on each request.

This article will guide you through installing and configuring Opcache to accelerate and optimize PHP performance on a Linux system.

What is Opcache?

Opcache is a built-in opcode caching mechanism for PHP that stores the compiled bytecode of PHP scripts in shared memory.

When a PHP script is executed, Opcache checks if a compiled version is available in memory. If it is, Opcache bypasses the parsing and compilation steps, resulting in faster script execution.

This significantly improves response times and reduces the server load, making it an essential tool for optimizing PHP applications.

Installing Opcache in Linux

Before installation, it’s a good practice to update your package repository to ensure you have the latest package information.

sudo apt update  [On Debian/Ubuntu]
sudo dnf update  [On RHEL/CentOS]

If you’re using a Debian-based system like Ubuntu, you can install Opcache via the php-opcache package.

sudo apt install php-opcache

If you’re on a Red Hat-based system like CentOS, you can install Opcache using the following command:

sudo yum install php-opcache

After installing Opcache, you can verify its installation by running:

php -m | grep opcache
OR
php -i | grep opcache

If you see opcache in the output, it means Opcache is installed successfully.

Configuring Opcache in Linux

Once Opcache is installed, you need to configure it in the PHP configuration file (php.ini) at the following locations, depending on your installation.

You can find the location of your php.ini file by running:

php --ini

To edit the configuration file, use a text editor (e.g., Nano or vim):

sudo vi /etc/php.ini

Add or modify the following Opcache settings:

; Enable Opcache
opcache.enable=1

; Set the memory size for the Opcache (e.g., 128MB)
opcache.memory_consumption=128

; Set the maximum number of scripts to cache
opcache.max_accelerated_files=10000

; Set the cache validity time in seconds
opcache.revalidate_freq=2

; Enable file validation for updated scripts
opcache.validate_timestamps=1

; Set the timeout for a request before it is terminated
opcache.max_file_size=2M

; Enable opcache for the CLI
opcache.enable_cli=1

Explanation of Settings:

opcache.memory_consumption: The amount of memory allocated for the Opcache. You can adjust this based on your server’s RAM.
opcache.max_accelerated_files: The maximum number of PHP scripts that Opcache will cache.
opcache.revalidate_freq: The frequency (in seconds) at which Opcache checks for script updates.
opcache.validate_timestamps: If enabled, Opcache checks for changes in scripts and invalidates cached scripts if they have changed.
opcache.enable_cli: Enables Opcache for the command-line interface.

After making the changes, save the file and restart your Apache web server for the changes to take effect.

sudo systemctl restart apache2
OR
sudo systemctl restart httpd

If you are using Nginx, use:

sudo systemctl restart nginx

Testing Opcache in Linux

To ensure that Opcache is working correctly, you can create a PHP file (info.php) with the following content in your web server’s document root (e.g., /var/www/html/).

<?php
phpinfo();
?>

Access the file through your web browser:

http://your_server_ip/info.php

Look for the “Opcode Caching” section in the output. If Opcache is installed and configured correctly, you should see information about the Opcache settings.

Monitoring Opcache in Linux

To monitor Opcache performance, you can use various tools, such as the opcache-gui, to visualize cache statistics.

git clone https://github.com/amnuts/opcache-gui.git
sudo mv opcache-gui /var/www/html/

Access the GUI in your browser:

http://your-server-ip/opcache-gui

Alternatively, you can also use command-line tools to get detailed information about cache performance. For example, to see the Opcache status from the command line, you can use the following command:

php -i | grep opcache

This command will display Opcache-related information, including memory usage and cache hit rates.

Conclusion

Installing and setting up Opcache is an easy process that can greatly improve your PHP applications by reducing the overhead of script execution and allowing your web server to handle more requests efficiently, resulting in faster response times and an improved user experience.

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Ravi Saive

I am an experienced GNU/Linux expert and a full-stack software developer with over a decade in the field of Linux and Open Source technologies

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35 Comments

Leave a Reply

reza

August 29, 2015 at 2:57 pm

hi

i already installed xcache with litespeed web server.
but after 1 or 2 weeks , i see the wordpress sites give 500 internal server error.
so i unistalled that :( .
Reply
shamrat

June 8, 2015 at 3:52 am

hi, I am using centos 5.6 with pleask 12 which has multiple version of php. above tutorial places the xcache with php 5.3 but how to put it on php 5.6 running as one more version on plesk. thanks in advanced.
Reply
- Ravi Saive
  
  June 8, 2015 at 11:01 am
  
  @Shamrat,
  then you need to compile XCache for the Php version you want to have..
  Reply
shafira

March 12, 2015 at 7:19 am

Hi, thanks for this tutorial, i was install it on my LEMP server on centos 6 and i was configuration like this tutorial for access xcache admin panel but when every time iam login, the login box still appear,,, i was restart my nginx and php-fpm but still not work.
Reply
- Ravi Saive
  
  March 12, 2015 at 10:53 am
  
  @shafira,
  Have you checked logs for any errors..and also have you generated and added correct md5 password to Xcache.ini file?
  Reply
Victor

January 13, 2015 at 2:38 pm

Hello Ravi, great guide on installing XCache but I am having a problem. When I run the command to install the xcache that is yum install php-xcache xcache-admin I get the error No package available.

What could be the problem?
Reply
- Ravi Saive
  
  January 13, 2015 at 4:24 pm
  
  @Victor,
  May I know on which version of Linux distro you’ve tried.
  Reply
Ben

November 10, 2014 at 3:13 am

Hi Ravi,
thx for your instructions on installing Xcache. I am wondering about the multi site use case: I have a Virtualmin setup on a VPS with a handful of users with individual web folders running mod_fcgid.

Do I have to take any precautions here?

Another thing: I wonder a bit about the admin setup. I have made a symlink from one of the web folders to /usr/share/xcache and can see the stats for that particular website. Is that the way to to – is there no way of getting a look at the whole picture ie. all web site cache statistics in the same admin screen?

Best regards,
Ben
Reply
- Ravi Saive
  
  November 10, 2014 at 4:47 pm
  
  @Ben,
  1. No need to take any precautions, as Xcache is just for caching PHP files and accelerating site performance.
  2. No idea about this..but I think you can get it by doing little trick to xcache configuration file..
  Reply
Kalim

October 29, 2014 at 12:21 pm

@Ravi,

When i tried to install php-xcache xcache-admin it by default installing php,php-common and php-cli dependencies (5.3 version), which i don’t need.

It there is way through which i can use PHP 5.5.6 with xcache or apc?
Reply
- Ravi Saive
  
  October 30, 2014 at 3:16 pm
  
  Which OS and PHP version you currently using?
  Reply
Kalim

October 29, 2014 at 11:37 am

Hi Ravi,

I have installed PHP 5.5.6 from source including pthread. But when i installed XCache from yum, I am unable to view XCache details in phpinfo nor in by executing php -v command.

OS :- CentOS 6.5

Can you please help me out.

Thanks in advance.
Reply
- Ravi Saive
  
  October 29, 2014 at 11:45 am
  
  @Kalim,
  Have you install php-xcache package? or you restarted Apache after installing XCache?
  Reply
Dante

November 22, 2013 at 4:48 pm

Hi i get the following error when i try to install xcache, can you help with suggestion on how to fix and install properly.Thanks

Error: Package: xcache-admin-3.0.4-1.el6.noarch (epel)
Requires: php-xcache = 3.0.4-1.el6
Available: php-xcache-3.0.0-2.el6.remi.1.x86_64 (mt_dv_extras)
php-xcache = 3.0.0-2.el6.remi.1
Installing: php-xcache-3.0.1-1.el6.remi.x86_64 (mt_dv_extras)
php-xcache = 3.0.1-1.el6.remi
Error: Package: php-xcache-3.0.1-1.el6.remi.x86_64 (mt_dv_extras)
Requires: php(zend-abi) = 20100525-x86-64
Installed: php-common-5.4.13-1.el6.remi.x86_64 (installed)
php(zend-abi) = 20100525-x86-64
Available: php-common-5.4.10-1.el6.remi.x86_64 (mt_dv_extras)
php(zend-abi) = 20100525-x86-64
Available: php-common-5.4.11-1.el6.remi.x86_64 (mt_dv_extras)
php(zend-abi) = 20100525-x86-64
Available: php-common-5.4.12-1.el6.remi.x86_64 (mt_dv_extras)
php(zend-abi) = 20100525-x86-64
Error: Package: php-xcache-3.0.1-1.el6.remi.x86_64 (mt_dv_extras)
Requires: php(api) = 20100412-x86-64
Installed: php-common-5.4.13-1.el6.remi.x86_64 (installed)
php(api) = 20100412-x86-64
Available: php-common-5.4.10-1.el6.remi.x86_64 (mt_dv_extras)
php(api) = 20100412-x86-64
Available: php-common-5.4.11-1.el6.remi.x86_64 (mt_dv_extras)
php(api) = 20100412-x86-64
Available: php-common-5.4.12-1.el6.remi.x86_64 (mt_dv_extras)
php(api) = 20100412-x86-64
You could try using –skip-broken to work around the problem
You could try running: rpm -Va –nofiles –nodigest
Reply
- Ravi Saive
  
  November 22, 2013 at 5:50 pm
  Seems your old packages are conflicting with new ones. So, fix such errors you must remove older version of php-xcache and php-common.
```
# yum remove php-xcache php-common
```
  And then try to install it again.
```
# yum install php-xcache php-common
```
  Reply
  - Dante
    
    November 23, 2013 at 10:35 am
    
    Dependencies Resolved
    
    ================================================================= Package Arch ================================================================= Removing:
    php-common x86_64 Removing for dependencies:
    SSHTerm noarch cs-gs x86_64 php x86_64 php-cli x86_64 php-devel x86_64 php-gd x86_64 php-imap x86_64 php-ldap x86_64 php-mbstring x86_64 php-mcrypt x86_64 php-mysql x86_64 php-odbc x86_64 php-pdo x86_64 php-pear noarch php-snmp x86_64 php-xml x86_64 php-xmlrpc x86_64 plesk-core x86_64 plesk-l10n noarch pp-sitebuilder noarch psa x86_64 psa-atmail noarch psa-backup-manager x86_64 psa-backup-manager-vz x86_64 psa-fileserver x86_64 psa-firewall x86_64 psa-horde noarch psa-imp noarch psa-ingo noarch psa-kronolith noarch psa-libxml-proxy x86_64 psa-migration-agents x86_64 psa-migration-manager x86_64 psa-mimp noarch psa-miva x86_64 psa-mnemo noarch psa-passwd noarch psa-php5-configurator x86_64 psa-spamassassin x86_64 psa-turba noarch psa-updates noarch psa-vhost noarch psa-vpn x86_64 psa-watchdog x86_64 ===========================================================================================================================================================================
    Version Repository Size
    ===========================================================================================================================================================================
    5.4.13-1.el6.remi installed 6.2 M
    0.2.2-10.11092910 installed 4.9 M
    2.0.0-cos6.build110120608.16 installed 845 k
    5.4.13-1.el6.remi installed 9.1 M
    5.4.13-1.el6.remi installed 7.7 M
    5.4.13-1.el6.remi installed 12 M
    5.4.13-1.el6.remi installed 665 k
    5.4.13-1.el6.remi installed 199 k
    5.4.13-1.el6.remi installed 109 k
    5.4.13-1.el6.remi installed 2.5 M
    5.4.13-1.el6.remi installed 86 k
    5.4.13-1.el6.remi installed 447 k
    5.4.13-1.el6.remi installed 178 k
    5.4.13-1.el6.remi installed 348 k
    1:1.9.4-12.el6.remi.1 installed 2.2 M
    5.4.13-1.el6.remi installed 107 k
    5.4.13-1.el6.remi installed 622 k
    5.4.13-1.el6.remi installed 153 k
    11.0.9-cos6.build110120608.16 installed 79 M
    11.0.9-cos6.build110120827.16 installed 21 M
    11.0.10-38713.12081600 @SITEBUILDER_11_0_10-dist 181 M
    11.0.9-cos6.build110120608.16 installed 473 k
    1:1.05-cos6.build110120606.19 installed 13 M
    11.0.9-cos6.build110120608.16 installed 8.5 M
    11.0.0-cos6.build110120123.10 installed 1.6 k
    11.0.9-cos6.build110120608.16 installed 367 k
    11.0.9-cos6.build110120608.16 installed 540 k
    3.3.13-cos6.build110120606.19 installed 20 M
    4.3.11-cos6.build110120606.19 installed 12 M
    1.2.6-cos6.build110120606.19 installed 5.1 M
    2.3.6-cos6.build110120606.19 installed 6.3 M
    2.7.8-0.301910 installed 1.2 M
    11.0.9-cos6.build110120608.16 installed 169 k
    11.0.9-cos6.build110120608.16 installed 1.0 M
    1.1.4-cos6.build110120418.19 installed 2.9 M
    1:5.06-cos6.build110120606.19 installed 4.5 M
    2.2.5-cos6.build110120606.19 installed 4.1 M
    3.1.3-cos6.build110120606.19 installed 3.7 M
    1.6.2-cos6.build110120608.16 installed 6.4 k
    11.0.9-cos6.build110120608.16 installed 159 k
    2.3.6-cos6.build110120606.19 installed 6.1 M
    11.0.9-cos6.build110120704.10 installed 0.0
    11.0.9-cos6.build110120606.19 installed 159 k
    11.0.9-cos6.build110120608.16 installed 1.9 M
    11.0.9-cos6.build110120608.16 installed 2.9 M
    
    Transaction Summary
    ============================================================================================================================================================================================================================================
    Remove 45 Package(s)
    
    Installed size: 425 M
    Is this ok [y/N]: n
    
    sorry for the long post just want to make sure that i am doing the right thing, alot of sites on the server. This is what i get when i run yum remove php-xcache php-common, I believe clicking y will remove just the php-common and not affect anything else? Thanks.
    Reply
    - Ravi Saive
      
      November 23, 2013 at 5:10 pm
      
      It will not affect anything just updates to latest versions, go ahead..
      Reply
      - Dante
        
        November 25, 2013 at 11:50 am
        
        Hi i clicked yes and it seems it screwed up my server?
      - Ravi Saive
        
        November 25, 2013 at 6:13 pm
        
        NO! it will not harm your server at all..
    - Daniel
      
      December 2, 2013 at 2:07 pm
      
      Remove 45 Package(s)
      Installed size: 425 M
      
      hhahahaaa OMG removing 425mb? LOL .. isn’t it like 20% of all CentOS ? :D hahahaa… I would’ve NEVER blindly accept such removal, before I know what each package is used for…
      
      Ravi, I really like your blog and happy I found it. I trust your experience.
      
      But can you explain what was that process of removing 45 packages, and how come it was safe actually? it will remove them and automatically reinstall new package versions or something?
      
      Thanks :)
      Reply
      - Ravi Saive
        
        December 2, 2013 at 2:24 pm
        
        It seems you are using older version of OS and lot’s of packages need to be upgraded to install latest Xcache on the system.
leon

August 25, 2013 at 4:41 pm

thanks but i have two questions in mind

1- The latest xcache version is 3.0.3 how we can update to it

2-when trying to access xcache admin panel i am getting error

Forbidden

You don’t have permission to access /xcache on this server.

i have checked permissions and they are ok
Reply
- Ravi Saive
  
  August 25, 2013 at 10:48 pm
  
  To get latest 3.0.3 version you need to compile it from source and for permission issue, open the xcache.conf file under /etc/httpd/conf.d/ directory and add Allow from all.
  Reply
- all4pages
  
  August 1, 2014 at 3:24 pm
  
  on Debian it can be the folder xcache/admin/ not only xcache/
  http://www.domain.de/xcache/admin
  
  or you setup your virtualhost to
  /var/www/xcache/admin/
  
  have fun!
  Reply
Tapas

May 9, 2013 at 12:31 am

Hi Ravi,

The reference URL for configuration given on step 2 is giving 503.
Can you please elaborate the configuration or can you give other reference URL?

Thanks
Reply
- Ravi Saive
  
  May 9, 2013 at 11:17 am
  
  The Configuration URL is working fine. Can you check again..
  Reply
Insignia

May 7, 2013 at 6:56 pm

Just want to verify if my intuitions is correct that xcache can also be installed or be configured as part of lampp?..
Reply
- Ravi Saive
  
  May 7, 2013 at 7:00 pm
  
  Yes! It can be installed and configured as part of LAMP based environments.
  Reply
  - Insignia
    
    May 7, 2013 at 7:13 pm
    
    oh thank you for affirming my query.
    Reply
Vladimir

May 3, 2013 at 2:46 pm

Does this automaticaly caches the compiled php script? Or we need to tell it what scripts it should cache?
Reply
- Ravi Saive
  
  May 3, 2013 at 3:11 pm
  
  Yes, it automatically caches all php scripts.
  Reply
kashyap

May 2, 2013 at 4:04 pm

I am getting below error :
Error: php-xcache conflicts with php-pecl-apc-3.1.9-2.el6.x86_64
plz help
Reply
- Ravi Saive
  
  May 2, 2013 at 4:06 pm
  First, remove existing apc package with the help of following yum command and then try again.
```
yum remove php-pecl-apc
```
  Reply
  - kashyap
    
    May 2, 2013 at 5:21 pm
    
    I hope it will not disturb existing setup which run on php?
    Reply
    - Ravi Saive
      
      May 2, 2013 at 7:42 pm
      
      Not it will not impact any existing setup.
      Reply