How to Install PHP-APC on your RPi to speed up your Apache Server
A Tutorial by D.M. Wiig
In a previous tutorial I discuss how to install a LAMP stack on your RPi and set it up as a web server. I have been hosting this WordPress site on my RPi now for serveral months. It has been running quietly and with low power drain 24/7 with virtually no down time. I have a fair amount of content on the site and it has been averaging around 50 or more visits per day since I got it up and running.
While the RPi is not going to have the speed of a professional grade server it does a credible job in applications where the load is reasonable and spread out evenly over the day. There are numerous tips and tricks to fine tune the Apache server that runs in the LAMP stack. One of the most effective and quickest tuneups is to install the program PHP-APC which is an alternative caching program for PHP files. WordPress serves up its content dynamically using PHP so having an efficient caching system for PHP will speed up serving content.
To install PHP-APC on an RPi running the Debian Wheezy Raspian OS open a terminal screen and issue the following command from the command prompt:
pi@raspberrypi / $ sudo apt-get install php-apc
The application will download and install. When the install is complete locate the file “20-apc.ini” The file should be installed in the /etc/php5/conf.d directory. Open the file in the nano editor with the commands:
pi@raspberrypi / $ cd /etc/php5/conf.d
pi@raspberrypi /etc/php5/conf.d $ sudo nano 20-apc.ini
The file will open in the editor and should see the following lines:
GNU nano 2.2.6 File: 20-apc.ini
Change the setting apc.sh_size=12M to a larger size such as 20M or so to start. Depending on your needs the size of the cache can be expanded as needed. Press Ctrl-o to save the file and Ctrl-x to exit back to the command prompt. Restart the server with the command:
pi@raspberrypi / $ sudo apachectl restart
Your Apache server should now be up and running with a larger and faster cache. I do not have any benchmarks to cite, but my WordPress application seems to respond noticeably faster with the apc cache installed. There are many other methods to fine tune your RPi as a web server including installing several alternatives to the Apache server. These are the subject of future tutorials.