Hello, have you find a solution for this annoying problem? I have exactly the same on two HP Proliant DL 580 G5 servers with debian squeeze and xen hypervisor 4.0. uname -a Linux xen-p01 2.6.32-5-xen-amd64 #1 SMP Sun May 6 08:57:29 UTC 2012 x86_64 GNU/Linux Time jumps forward 50 minutes. Is it a debian kernel bug? A xen bug? A hardware bug?