title: Redis - Can data size be greater than memory size?
body: <p>I'm rather new to Redis and before using it I'd like to learn some important (as for me) details on it. So....</p>
  <p>Redis is using RAM and HDD for storing data. RAM is used as fast read/write storage, HDD is used to make this data persistant. When Redis is started it loads all data from HDD to RAM or it loads only often queried data to the RAM? What if I have 500Mb Redis storage on HDD, but I have only 100Mb or RAM for Redis. Where can I read about it?</p>