Sampling keys in a Redis cluster
We love Redis here at zulily. We store hundreds of millions of keys across many Redis instances, and we built our own internal distributed cache on top of Redis which powers the shopping experience for zulily customers. One challenge when running a large, distributed cache using Redis (or many other key/value stores for that matter) is the opaque nature of the key spaces. It can be difficult to determine the overall composition of your Redis dataset, since most Redis commands operate on a single key.