I already have consumers seamlessly reconnecting to a new server during a HA event. Basically what I do on failover is to create a new consumer on the new server, replace IDs and re-register the Callback handler. The server at this point will think it's a new client coming. In case of durable subscribers/queues and persistent messages you will have the queue refilled There are some issues that I would like to discuss now: If the consumer receives a message from CallBack but if it didn't send an ACK yet, after the failover, the server not knowing the message might throw an exception (messageId not known). There are a couple of use cases we have to consider. - Persistent Messages. (how to treat a redelivery). - Should we send the list of previously ACKs to the server? - Should we ignore ACKs for non existent messages on the server? Second point also: What to do when a durable subscriber gets the queue refilled? - The client will probably receive the message again. I would just ignore redeliveries. I'm considering having a conference call with developers about these possibilities. Clebert Suconic View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3978860#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...