Tim 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. | Because we are not going to modify the client code to NOT send acknowledgments for messages being delivered. The acknowledgment-sending portion of the client-side aspect stack is "unaware" that it just went through a failover and it will dully continue to behave as designed, i.e. sending acknowledgments for messages being consumed. It's the secondary server job to realize that the acknowledgments arriving for deliveries it actually does not have (or better said, did not create by actually sending messages) are legit, and are generated by "salvaged" non-persistent messages. Does it make sense? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3980952#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...