I'm messing around with the HTTP Session Passivation feature in JBoss 5.0.0 Beta1 for the first time, and I'm a bit confused about something: do I need to configure *every* node in my cluster to do passivation, or just a single node? My gut instinct is that it should work either way (which I'm in the process of verifying). If it does work either way, are there any benefits or tradeoffs one way or the other? If not, could somebody explain what the issues are?
you gut instinct is correct :) It should work either way. However, the servers in the cluster that don't have their Http Session passivation turned on, will not be able to passivate sessions maintained by their respective cluster manager.
You can see the benefits, trade offs, and a whole lot more on the wiki :
http://wiki.jboss.org/wiki/Wiki.jsp?page=HttpSessionPassivation
http://wiki.jboss.org/wiki/Wiki.jsp?page=HttpSessionPassivationDesign