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From Rainer Jung <>
Subject Re: mod_proxy_balancer/mod_proxy_ajp TODO
Date Mon, 19 Jun 2006 20:44:36 GMT
Henri Gomez wrote:
> For the load-balancing algorythm, do you plan to propose a bunch of
> pre build algos and let users select the right one for their use or
> allow externals modules ? We could see that like mod_jk / mod_proxy
> modules like apache modules  does for HTTP...

A pluggable balancing strategy sounds nice. What I'm not sure about, if 
the size of problem is big enough to justify the work.

All three existing strategies at the moment are based on the same basic 
principles. All strategies use the same unsigned 64Bit to describe the 
actual load value and there are three possible places where the values 
are adjusted: pre request, post request and during maintenance (called 
in regular intervals).

Busyness: increment pre request, decrement post request, no op during 

Traffic and Requests: increment pre request, no op post request, decay 
during maintenance.

Traffic and Requests use different values to increment, Traffic uses the 
amount of bytes transmitted, Requests always increments by one.

So to be able to implement interesting balancing strategies, the plugins 
would need to be able to use request/response data, like performance, 
load, error status etc.

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