We have discovered an interesting issue with a new production system we are setting up, whereby java processes on the VM guest are looping, consuming all available CPU. They are effectively locked up, and need to be killed (with -KILL).
Experimentation has demonstrated to us that this only occurs when the sites are running with VMI Paravirtualization turned ON, with multiple Virtual CPUs assigned to the guest - with paravirt on and 1 CPU, there is no problem. Turning paravirt off, and keeping 4 CPUs also corrects the problem.
We are running Ubuntu 8.04 (hardy) - 32-bit - with kernel 2.6.24-24-server. Tested JDK is jdk1.6.0_06, though we are about to check against the latest.
Has anyone else seen major problems with Paravirtualisation like this?
