Java – JVM tuning in JBOSS AS 7

You need to provide a lot more information:

1) How much RAM is available on the box? Is Tomcat the only thing running?
2) Is this a 32bit or 64bit VM?
3) How many CPU's/cores are on this box?
4) What major version of the jdk are you running? 1.4, 5, or 6?

The answers to those questions will allow you to set boundaries for the heap.

Once you get past that, questions about the application may need to be answered - how many objects are long-lived (ie cache), and how many are short lived (less than 5 seconds before they go out of scope).

These questions will tell us what % of the heap can be used for Eden, and what percent needs to be used for the old generation.

Update

Well, if your Tomcat is long-running, then adding the '-server' flag would likely be beneficial. Given your constraints, unless you know your apps inside and out, it's probably best to leave it up to ergonomics to determine the best ratios and collector. Java tuning is much more an art than it is a science. Start here: http://java.sun.com/javase/technologies/hotspot/gc/gc_tuning_6.html, then look for tools like GCHisto, and VisualGC to help you visualize what's going on inside the VM.

I'd recommend against options IPFIREWALL_DEFAULT_TO_ACCEPT. The default is to Default to Deny. The firewall comes up with just one rule deny ip from any to any and stays that way until a script configures exactly what traffic should get through.

Follow-Up Note: RSA (one of the world's leading security technology companies) was hacked recently when part of their firewall was disabled during a maintenance window. This really underscores how quickly a system can be compromised given the right conditions.

If you insist on disabling the firewall until you explicitly block unwanted traffic, please consider using the sysctl available by adding net.inet.ip.fw.default_to_accept=1 to loader.conf. This has the added benefit of being easily modified (no recompiling the kernel) if you change your mind at some point in the future.