Riak_cache is a project mainly written in ..., it's free.
Drupal Riak cache backend
h1. Drupal Riak cache backend
h2. Installation
git clone https://github.com/basho/riak-php-client.git
patch -p0 < riak-php-client.patch
$conf['riak_connection'] = array('host' => 'localhost', 'port' => '8098');
include_once DRUPAL_ROOT .'/includes/cache.inc';
include_once DRUPAL_ROOT .'/sites/all/modules/riak_cache/riak_cache.inc'; $conf['cache_default_class'] = 'DrupalRiakCache';