Since I posted this, I have done some research. Our server has 1gb of ram. I am now using the following JVM options:
The defaults were 64mb for both.
So far things seem to be running smoothly. I am keeping an eye on memory usage with 'top'.
Question: is a gig of ram enough? Take into consideration that we are using JBoss AS 4.2.1, JBoss Portal 2.6.1, and JBoss Forums and Wiki portlets.
We plan on having around 200 to 1000 users.
How much memory should we be looking at for our needs? Any other scalability issues I should keep in mind?
I, too, have run into this problem. As it turned out, we were distributing our Oracle JDBC driver .jar with the web application and when we removed it and placed it into server/[default]/lib the problem went away. I have *no* idea why this worked, but we are sticking with it as I have no time to become an expert on JBoss classloading, etc.
(We also bumped up our PermGenSpace to 256M, but this only temporarily solved the problem. Removing the JDBC .jar fixed it "permanently".)