The traditional way replicated systems are architected is to physically co-locate the write-ahead log (WAL) on the nodes where the state is being maintained. Then a consensus protocol like Paxos or Raft is used to make sure the log on each replica agrees. With many classical databases that have been around a while, instead of consensus there may be a configuration-driven primary/backup scheme. This converged approach is not that different logically even with the physical decoupling of compute an...