I am using Centos 5.2 as both my XEN host and guests. Both the XEN host and each XEN guest are up-to-date with the latest CentOS 5.2 updates. I've noticed over time that sometimes using init 6 (or init 0) in the guest works flawlessly and other times the guest will reach "Restarting System"/"System Halted" and hang. When this hang occurs the only way to finish the shutdown/reboot is to destroy the virtual machine and also one of the CPUs on the XEN host is maxed out at 100% CPU. Trying to diagnose this hang, I have found that restarting the xend and xendomains daemons restores the ability to init 6/init 0 the guests. I have not as yet narrowed the problem further. I was wondering if anyone else has seen this behavior and if so if there is a known fix, if not, how to properly report this issue so it can eventually be addressed? Brett