Hi, Update: probably reproduced the bug in Xen on a Sun Fire X4200 M2 ;( After 4.5 hours, it froze so hard that I could not power it off via the iLOM, even Num Lock wouldn't work. After rebooting, lock-ups occurred in about 5-30 minutes. There is nothing in the syslog. After downgrading the Dom0+Xen kernel, the problem persisted. Downgraded all Dom0 kernels as well, waiting for next lockup :I Elmar