Installing memcached on Ubuntu for wordpress and phpbb

As an application maintainer you always look for the best performance in your application and website. At one point in your quest for the best performance you will undoubtedly trip over memcached.

In short memcached is (quote); Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load. Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.

That said, installing is a no brainer as well. On Ubuntu you simply need to do the following:

apt-get install memcache
apt-get install php5-memcached

That’s it. Your system takes care of the rest and you will have your first memcached server up and running. Of course, the final step will be to restart apache in order for php to pick up the changes.

Now, memcached alone is of no good use, if your code/application can’t work with it. Thus here I’ll outline 2 examples.

WordPress: Memcached with the W3C total cache plugin

First off, if you aren’t using the awesome W3C Total Cache plugin you should now run install the plugin immediately (just search for w3 cache in the plugin section of the wordpress administration). Even if you are not using memcached it will boost the performance of your WordPress site manifold.

Now, to enable memcached for your WordPress site is as simple as selecting the memcached option for the cache. with the plugin you can even select what you want to place into the memcached cache. Quit slick.

Configuring phpBB to use memcached

Actually it took some time to figure this out, since the setting were not so apparent, so I’m hopping this helps others also. phpBB by default used the local disk for caching. This can be chanced in the config.php file in phpBB folder. Open it and ADD or change the following lines:

$acm_type = 'memcache';
@define('PHPBB_ACM_MEMCACHE_HOST', 'localhost'); // Memcache server hostname
@define('PHPBB_ACM_MEMCACHE_PORT', 11211); // Memcache server port
@define('PHPBB_ACM_MEMCACHE_COMPRESS', false); // Compress stored data
$load_extensions = 'memcache';

Especially the last line with “load_extensions” is important. Save the file and restart apache. Now phpBB will use the memcached server(s). Alone on a board with 800 users I have seen a massive speed improvement.

That’s it. Next up is to get all my CFML apps to work with memcached 🙂