The tx on node A will fail and rollback *provided* the tx on node B completes before node A starts to commit. If node A is already in it's prepare phase and node B broadcasts a commit, both txs will fail (node B unable to successfully prepare on node A, and node A unable to successfully prepare on node B) Internal versioning is on the node (as in, node in the tree structure) level. And this version info is replicated when modifications are replicated so this is consistent across a cluster. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4032685#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...