Why I like Redis. I’ve been getting a lot of useful work done with Redis recently. Redis is typically categorised as yet another of those new-fangled NoSQL key/value stores, but if you look closer it actually has some pretty unique characteristics. It makes more sense to describe it as a “data structure server”—it provides a network service that exposes persistent storage and operations over dictionaries, lists, sets and string values.
Think memcached but with list and set operations and persistence-to-disk. Cassandra - A Decentralized Structured Storage System. Redis - Google Code.