Install Memcache onto cPanel running CentOS

Memcached is a service that allows entire database tables to be stored in memory, drastically speeding up queries to those tables and alleviating database load. In WordPress and W3 Total Cache, the Memcached module allows you to store all cache tables in memory.

This guide can be used to set up Memcached on CentOS.

Install memcached through RPM

The easiest way to install Memcached is through a package manager such as yum or apt.

Now we can simply use yum (or apt) to install Memcached:

Afterwards you can confirm memcached is up and running by calling it.

Install the Memcache PECL Extension

Even though memcached is happily running on the server, it’s not accessible from PHP without the PECL extension. Fortunately this is a very easy process, just use the pecl command.

pecl install memcache

If the pecl install fails you will need to use the alternative method:

$ wget http://pecl.php.net/get/memcache-3.0.6.tgz
tar xvfz memcache-3.0.6.tgz
cd memcache-3.0.6
phpize
./configure
make && make install

Then add the memcache extension to your php.ini file, usually at /usr/local/lib/php.ini.

And finally restart Apache so that it will pick up the new extension:
/etc/init.d/httpd restart
Running phpinfo() on your webserver should now confirm that memcache is installed:

Set up Memcached as a service

Just having memcache installed will not do anything by itself, we need to actually start up some instances of it for our web server to connect to, and we need memcached to automatically start up when the server restarts.

For this we need to install a new script at /etc/init.d/memcached. For this I usually use a custom script that’s a bit crude, since it assumes that memcached is being used exclusively for our web server. However, most of the time this is true and it works just fine.

Download the memcached script (rename to just “memcached”).

So simply load this script into /etc/init.d. Then set the permissions on it to make it executable:

Then register the script to start up with the server:

Now you can start up memcached as a service.

And you can confirm that memcached has fired up several instances by checking ps.

And that’s it! You may need to change the /etc/init.d/memcached file to match your needs depending on what you’re using Memcached for.

Originally posted 2016-01-11 05:53:00.