About the use cases where strong guarantees are needed: for instance Disque (http://github.com/antirez/disque) provides strong guarantees of delivery in face of failures, being a pure AP system with synchronous replication of messages. For Redis 4.2 I'm moving Disque as a Redis module. To do this, Redis modules are getting a fully featured Cluster API. This means that it will be possible, for instance, to write a Redis module that orchestrates N Redis masters, using Raft or any other consensus algorithm, as a single distributed system. This will allow to also model strong guarantees easily.