Afaik Quartz uses DefaultDS and in a clustered environment your servers are likely to use the same database for JMS etc. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4207137#4207137 Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&p=4207137