"ovidiu.feodorov(a)jboss.com" wrote : | The client stack knows that the fail-over took place, so if the message is non-persistent, it doesn't need to send the ACK anyway (from the server's perspective, the message is lost), and if the message is persistent, it will be recovered on the fail-over server, so the ACK will arrive for a known message. Am I am missing something? | | This is all explained in my summary (previous post) and on the wiki page. So yes, on failover, any non persistent messages on the client side need to be removed from the list (since they will be lost on the server side) so the ACKs will never be sent, so there will be no exception. anonymous wrote : | What do you mean send the ids of every persistent message as part of the failover protocol. Who sends the ids? The messages are in database, until they are ACKed, and this is where the fail-over server will recover them from, and repopulate the queue. | The client needs to send the ids of any persistent messages. Yes, the server repopulates the queues but does not have enough information to populate the server consumer endpoint delivery list. This is what the ids are for. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3979005#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...