No, it will not have to double. A lot of that 1/2 GB is for the JVM code and the operating system is smart enough to shared the code between Java instances. Thus while the first instance will use up a lot of memory, a second instance will not use as much additional memory. Based on your heap size, you should be able to run two JBoss AS instances in 2GB of memory. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4200369#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...