Hi, I have a 4 node artemis 2.10 cluster on Linux configured for replication and colocated HA servers. I have been testing the failover and fail back but its not working as I would expect. When shutting down one server (A) in an HA pair the colocated backup on the second server (B) activate and process messages for the original server A. Now it doesn't process all the messages sent though but that's a different problem. The problems start when I bring up the original server A again. Server A starts, becomes live and joins the cluster but looking in the console there is no longer a collocated_backup_1 listing to show that it is providing a collocated backup to server B. It also seems to cause the server that was failed over to, server B, to go offline and not be "live" anymore. Server B also doesn't have the collocated_backup_1 shown in its console. Server B seems to be part of the cluster still but in the UI there is no green master node shown for it anymore - just a red slave node circle. Server B doesn't list any addresses or acceptors in the UI and connections to it fail. It seems like its shutdown its "live" server and is running as a backup only. If I shut server B down and bring it up, the roles are swapped. Now server B becomes live again and is shown as a master node (still no collocated_backup_01 though) and server A goes offline and appears only as a slave node. in the UI. Whether server A or B is in this "offline" backup-only state the value of the Node property in the cluster attributes shown in the UI is the same value for both. Prior to doing the failover test they have different node ids which makes sense. So there is a problem with the fail back in that it seems to only allow one of the nodes in the HA pair to ever be live after a failover event.
The only way to fix the issue with the pair is to stop both servers and remove the "colocated" backup directories from the data directory on both boxes before starting them again. At which point they come up correctly and both are live and they pair up as HA backups for each other again -- Sent from: http://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.html
