Diego wrote a great summary of the differences between Viewstamped Replication[1,2] and Raft on the Raft mailing list a few years ago[3].

[1] http://pmg.csail.mit.edu/papers/vr.pdf [2] http://pmg.csail.mit.edu/papers/vr-revisited.pdf [3] https://groups.google.com/forum/#!topic/raft-dev/cBNLTZT2q8o