viewstamped-replication-made-famous VS consensus

As an example of this in distributed systems:

There's a classic metastability issue in probably most implementations of state machine replication protocols such as Raft, where a lagging follower, if it sees an op that's newer than what it's expecting, must first repair and catch up its state (FIFO) before it can ACK back to the leader.

Apart from introducing latency in the critical path, this can lead to really bad queueing behavior where the lagging follower queues the latest request from the leader while it first catches up, but because this catch up can take seconds or minutes, in that time the pending request queue has also overflowed, and now we're back to state transfer catch up all over again, a vicious cycle.

Raft requires this bimodal latency distribution for correctness.

However, there is a new approach that we developed for TigerBeetle [1] to eliminate this bimodality and achieve constant ACK latencies from all followers, no matter their state, that we'll be sharing as part of Viewstamped Replication Made Famous [2], a $20,000 consensus challenge launching in September.

[1] https://www.tigerbeetle.com

[2] https://github.com/coilhq/viewstamped-replication-made-famou...

Firstly, I have spent a tremendous time working on this project (https://github.com/dolla-consortium/consensus), so just imagining you'll look at it, makes me happy.... I'll probably die of joy if you give me feedback ;-)