How many nodes max can be used when setup a etcd cluster

Question

I try to setup coreos etcd cluster for a datacenter.
How many nodes max i can setup in a cluster for it?

I and to add more nodes can help to increase the performance or not?

I didn't find the figure from the offical website. It only mentions 9 is ok.

Answer 1

To my knowledge, which I've got from running a small (3-5 nodes) coreos cluster and hearing from the coreos team themselves, up to 9 won't have any latency issues, maybe 10 if you're lucky, but after that the cluster has latency issues with keeping etcd the consistent on each node of the cluster, therefore 9 should be max if you want to play it safe.