"ovidiu.feodorov(a)jboss.com" Please consider this simple example: the non-persistent messages N1 (id = 1) and N2 (id=2), sent by the server A, sit in the client-side buffer. The server A fails, the VM goes down. The connection is re-established (transparently) to server B. Server B knows that is a secondary server for the connection that just has established (as a result of the failover protocol). So, it could naturally assume that there are undelivered non-persistent messages in the client-side buffer. Which have not been lost. It also learns that the id of the messages are 1 and 2 (as a result of the fail-over protocol). So, what is stopping the server B (again, knowing that is a secondary server that has just been failed-over to), to accept acknowledgments for non-persistent messages that have been salvaged this way? [/quote wrote : | | Still makes no sense. | | What's the point of sending an ack that's just going to be ignored? | | It's much easier to just not send it in the first place, you can still process the np messages in the client buffer, just completely pointless to send acks to the server for them. | View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3980946#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...