http://redis.io/topics/memory-optimization
http://redisplanet.com/redis/under-the-hood-of-redis-hash-part-2-and-list/
http://redisplanet.com/redis/under-the-hood-of-redis-hash-part-1/
https://github.com/sripathikrishnan/redis-rdb-tools/wiki/Redis-Memory-Optimization
http://openmymind.net/Back-To-Basics-Hashtables/
http://openmymind.net/Back-To-Basics-Hasthables-Part-2/
http://redisplanet.com/redis/under-the-hood-of-redis-hash-part-1/
http://redisplanet.com/redis/under-the-hood-of-redis-hash-part-2-and-list/