How to set the heartbeat interval?

[xujianrj]

HI
I have two ETCD instance running , one is running at Canada , and one is running at China.
The ping delay is about 500ms .
I'd like the two ETCD instance working in clustering .
I am wonder how long shall I set the "-peer-heartbeat-interval".
Is it 50ms ,500ms or 1000ms?
And also shall I set the "-peer-election-timeout" 5000ms ?

[yichengq]

https://github.com/coreos/etcd/blob/master/Documentation/tuning.md
This is a fantastic tutorial for parameter setting.
I think the heartbeat interval should be at least 1s.
@xiangli-cmu Correct?

[xujianrj]

I have read this document , I am not sure how to calculate the time.
if my ping delay is 500ms ,why I need to set to 1s ?
Is it because the tcp protocol need the double time?

[bmizerany]

@xujianrj You need to account for a variation in latency. If you have latency l, heartbeat h, and a buffer for some normal variation in latency x, then you can determine your timeout to be: l+h+x.