Hi, I have been working on load balancing Apache/Tomcat clusters. In mod_jk, the fail-over is done in the function get_most_suitable_worker. Basically if the worker who initiated the session is available (i.e. not in error state), use it, otherwise loop through the workers and select either the one with the lowest load balancing value OR one that has been in error for at least WAIT_BEFORE_RECOVER seconds if such worker exists. Thus the faulted workers are privileged when selecting a worker for a request whose worker designated by the jvmroute is not available.
There is though no algorithm implemented which will map all requests to the same 'backup' worker, thus either the worker which created the session (the one in the jvmroute) is available, either another worker will be selected, but in the latter case there is no guarantee that 'second choice' will be the same for the next requests. Therefore re-routing does exist in mod_jk and works, but it is not optimal for your case, the worst thing being the dispatching of incoming requests to a different worker each time, your distributed session management would therefore give the parenting of the session to a different worker each time, far from optimal! Mathias. -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
