> BTW Paxos also has a leader - this is what makes these protocols efficient. They need only the linear number of messages instead of the quadratic "everybody t

> BTW Paxos also has a leader - this is what makes these protocols efficient. They need only the linear number of messages instead of the quadratic "everybody talks to everybody" design. Okay, but again, this means that the leader is the bottleneck. In that case, I'd want the leader to be on beefier hardware than the other machines, and to not serve up any read requests, so all of its resources are devoted to leading. In order to accommodate this, you'd want to elect leaders from a pool of leaders which have the beefier hardware. And at that point, since you're only talking to the leaders when you write, rather than talk through to the leaders through the extra latency of the followers, just write to the leaders directly. And then at that point this looks suspiciously like the leaders are a sharded database and the followers are caches. Am I missing something?