[mutex007]

Assuming your 70ms in transit is accurate, although you have not provided details on how you measured that. 20ms svr processing time is only 50 inserts per second which is simply untenable in respect to a high performing rethink..

In effect if i wanted to do 10000 single writes per second typical of most interactive systems, i will need 200 nodes to pull that Off.

[coffeemug]

By default Rethink requires an fsync from disk to guarantee data safety. So a typical default query goes like this: client request -> network trip -> wait on disk fsync -> network trip -> ack. That's going to be really slow in any system, and makes 10k writes/sec pretty much impossible on any rotational disk.

In Rethink you can turn on soft durability which will allow buffering writes in memory. That would drastically speed up write performance. Another option is to use concurrent clients. Rethink is optimized for throughput and concurrency, so if you use multiple concurrent clients the latency won't scale linearly.