One idea: When retrying a send (or a send transaction) after failover, you could add a flag in the request (checkForDuplicates = true). On the server side, when it processes the request, if this flag is true, then before inserting the messages, you can check in the database to see if the messages already exist (pm.referenceExists()) and if so, you silently ignore the request. This isn't perfect, and doesn't cope with the case where the message is acked before the duplicate arrives, but to deal with that we need duplicate message detection via a cache or something. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4011583#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...