Thinking outloud: Using a listener to dynamically add regions sounds fine, although each region has its own overhead, that is storage and CPU costs. Maybe 1000s of regions is fine, but what about 10000 or more? And you might want to consider what happens when a region is empty, i.e. consider how region de-allocation works. It might be easier to extend and/or implement your own eviction policy that tracks regions. I would probably prototype and test your solution than go to the trouble to implement a new eviction strategy, however. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4221713#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...