If you haven't heard of Redis, you might want to check out Kevin van Zonnevald's blog post detailing how to install the memcached-like caching server, and how to code with it.
You can use Redis as a database, queue or a cache server. It stores its entire dataset in memory, so it's "crazy fast," van Zonnevald said.
But unlike memcached, the Redis dataset is not volatile.
His article is "meant to help PHP developers taking their first steps into the Redis world."