Ubuntu Servers :: Linux Freezes When Running A JVM Performance Test?

I am in the process of running a set of performance tests for the latest Sun JVM 1.6.0_20. I am using for that the dacapo test suite: [URL]

I ran the test suite very often with all sorts of settings, but recently it happened once that my Ubuntu system froze. I could still ping the machine, but nothing else was responding any more, no screen output, no ssh login, not possible to switch consoles. After rebooting the system the system logs were quiet. No single trace of any problem.

I am using a custom compiled kernel 2.6.34: Linux i7 2.6.34-custom-201005231602 #1 SMP PREEMPT Sun May 23 16:06:01 CEST 2010 x86_64 GNU/Linux and I am experimenting around with the -XX:+UseLargePages JVM switch the requires to set-up the hugetlbfs on the Linux system: [URL]

A similar issue happened in March 2010 on one of our CentOS 5.4 systems where we run a heavy load Java application on, where we had to hard power off the machine and after the reboot there was no trace of the problem in the logs. On that server we used JDK 1.6.0_17 and did not use hugetlbfs.

My first question would be what to do so that next time something like that happens I have more information available after the incident to debug and analyse the problem?