Hypersonic databases

[willemnoorduin]

We have implemented JBoss-clustering (JBoss 5.1.1.GA) with success, only to be production ripe, it is in general recommended to replace the Hypersonic Database with another (say Oracle or MySQL). The technical aspect is clear, just replace your hypersonic datasource with another JDBC Connector to DefaultDS and let JBoss take care of the rest. There are a few questions:

• I have seen one Hypersonic database connection per JBoss profile. Does this mean we have to implement n seperated Oracle databases when we run n JBoss profiles, or can you do it per cluster (so, if 4 JBoss-profiles form a JBoss cluster, point these to the same Oracle database ? Notice I am using Oracle here because I want to stress the cost aspect, and yes, I know that MySQL won't cost you anything).
• What information is saved to the database when you are using all the capacities of JBoss ? (I only saw one counter, but then again, I just ran some rediculously easy test application).

[wdfink]

Messaging and EJB timers are stored to the database.

A cluster should use the same database because you will share the informations (e.g. for failover).

Maybe the timer is special because it might happen that a timer will be started on each cluster node and you might avoid that, this is possible by changeing the ejb-timer configuration (the table name must be different for each node).

Also you application must share the data otherwise you have fuzzy results if WEB/EJB calls are loadbalanced.