Serializing cross-partition transactions is known as "external consistency" or "strict serializability"; that's what this game is about. The illusion of total o

Serializing cross-partition transactions is known as "external consistency" or "strict serializability"; that's what this game is about. The illusion of total order. :-) There is no single node that serves as a global coordinator. The "coordinator" as referred here is a stateless logical role for each transaction and every node in the cluster can do it on an ad-hoc basis. Our current performance numbers are much better but we don't have anything published quite yet. The bottleneck, so to speak, is the distributed, partitioned write-ahead log which is implemented in a pipelined version of Raft. It is not materially different than the Paxos or Raft-based rings that support replicas in aa Spanner-style leader-per-tablet two phase system. However it has better long-tail latency because a fixed subset of nodes resolves transactions instead of every leader regardless of location, and it is not subject to write skew across disjoint transactions. We are well aware of NBD. NBD is not designed for WAN latencies, and like you say, it pushes consensus complexity onto the developer. Certainly it is easier to reach higher theoretical throughput numbers when you do less work on faster hardware. I admire NBD but it doesn't make sense to compare a WAN system with a higher consistency guarantee to a LAN system with a lower guarantee. Fauna will support multiple consensus regions in the future to uncork aggregate throughput, at the cost of some explicit optimistic consensus across region boundaries. This is still a better story than explicitly locking on a read-committed isolation level which is subject to read and write skew in a way that cannot be architecturally overcome, even with locks.