‍Consensus algorithms in their theoretical and applied forms can be difficult to reason about. Often, these algorithms are solutions that have stumbled upon some good problems to solve. Unfortunately, the problems are evolving. And I don’t think these solutions are going to remain relevant much longer. Let’s start with defining the problems they solve:

Distributed Durability: In case of node failures, your data is guaranteed to be elsewhere.
Availability: The ability for the system to continue serving if some nodes have become unavailable.
Automation: If there is a failure, the system knows how to remedy itself without human intervention.

Raft is a consensus algorithm that is designed to be easy to understand. It's equivalent to Paxos in fault-tolerance and performance. The difference is that it's decomposed into relatively independent subproblems, and it cleanly addresses all major pieces needed for practical systems. We hope Raft will make consensus available to a wider audience, and that this wider audience will be able to develop a variety of higher quality consensus-based systems than are available today.