6.4 Redis Sentinel and Redis Cluster

Does your dataset fit in one machine's memory, and can one Redis process handle its write rate? The answers decide between the two ways of running Redis on several machines. A single Redis node has two limits: if it dies, the service stops, and it can hold only what one machine's memory and one main thread can handle.

Redis Sentinel addresses the first limit, availability, by automating failover for one dataset. Redis Cluster addresses the second limit, scale, by splitting the dataset across many nodes, and it includes failover as well