The major memory increase is because of JBCACHE-1383, which creates 16 CHM segments and 17 locks per node. We have not yet done a 2.2 release that includes the fix, which is reducing it to 4. You could build the latest 2.2.x branch to try it. The 3.0.0 Alpha release completely eliminates the problem (when using the MVCC locking mode). Perhaps you want to give that a try? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4166468#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...