Only vague thought that comes to mind is a concern about data versions with OL. That is, /a/b have a particular data version. Say a special DataVersion impl like we use in Hibernate caching for structural nodes, where we never report the node as being out-of-date. The removal destroys that on the backup node. Then the data owner writes /a/b/d. The special DataVersion impl doesn't replicate to the buddy for /a or /a/b, since the owner didn't think it had written to those nodes. So the buddy just inserts a default DataVersion. Now the trees are inconsistent. I guess, in general I think the idea of making changes to the backup tree when the data owner is still alive is a bad idea. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4121918#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...