It [i]may[/i] be that Apache will send the request elsewhere if the servlet engine associated with it is dead and further it may be the session will be essentially renamed with a new jvmRoute. I must admit that I do not know all of these details, though I suspect the latter portion can be gleaned fairly easily from the Tomcat source code -- that's the analogous role for Glassfish obviously irrespective of what Apache does at this moment.
Clearly I'd like to see the sessions be "migratable" when a servlet engine dies but a shared persistent backup of the session data exists. Just having the load balanced over multiple JVMs without any additional availability gains is still something, though.
I may or may not be able to find time to comb through the Tomcat sources for such information in the near future. Eventually I suspect I'll be looking to get full migratability in place, but that does not have to be part of step 1.
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