Jason and Manik, Thank you all for very quick and useful response. Re: balancing I'm afraid simple modulus won't make the tree deep. If I have 1,000,000 meters and written actively by 3 nodes (but I do have stickiness per node) then simple modulus like x = ID % 10000 fqn = /ROOT/x/ID ROOT still has 10000 direct nodes (which is according to Manik should be less than 500 direct children per node). I can do many level of by partitioning the bits of a number. Here, I really want to know the best practice which I hope you guys document somewhere, such as, how many nodes should I have under ROOT? How many direct nodes under a node? And how deep the tree can go? How bad is unbalanced tree? On other cache system I ended up using multiple caches to spread the load and concurrency using simple modulus b/c everything is flat. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4166270#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...