Fair Proxy Balancer

Rt Ibmer rtibmx at yahoo.com
Tue May 6 17:03:06 MSD 2008

Hi  Grzegorz - thanks for this module. It looks very nice. Can you explain how you keep track of how busy a backend server is? In other words, what do you use to determine its performance?

In our case we would like to use your fair proxy balancer so that machines that are responding faster get more requests than slower machines.

For instance, on of our upstream servers runs on the same machine as nginx.  From nginx's logs we can see that local upstream usually responds about 3-5ms faster than the other upstreams because it doesn't have to go over the local network to reach the upstream in that case.

So if I was using 'fair' would it realize 'hey upstream x is completing requests 3-5ms faster than upstreams y and z so I'm going to route more requests to upstream x"?  Or does your module not take that measure into account?

Early on while our traffic is still ramping up, requests may come in at a slow rate to the point where all requests could be served faster by the local upstream, with the other upstreams being available in case traffic should spike or in case one of the other upstreams goes down. In that scenario is it possible that your module would wind up sending all traffic to just the local instance if its ms response times were better than the other upstreams (I would not mind if it would, just trying to understand how it 'thinks' better). Thanks!

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