BFT state machine replication is well-understood and well-defined: use N of M agreement for inputs and run them through a deterministic state machine. Optionally, do N of M signature of outputs.
OTOH what are properties of failover? "Failover" seems like an attempt to cheat on Byzantine generals' problem: Generals send mail and the confirm results in a Zoom call. But what if Zoom doesn't work? What are the assumptions for 1+ redundant components/failover/STONITH?
BFT state machine replication is well-understood and well-defined: use N of M agreement for inputs and run them through a deterministic state machine. Optionally, do N of M signature of outputs.
OTOH what are properties of failover? "Failover" seems like an attempt to cheat on Byzantine generals' problem: Generals send mail and the confirm results in a Zoom call. But what if Zoom doesn't work? What are the assumptions for 1+ redundant components/failover/STONITH?