Hello list, we have one dom0 Domain on debian sarge and xen 3.0.1 with several domU domain also setup with debian sarge. On the dom0 domain there is a ntpd running and date shows me the correct time. When starting a domU domain, the kernel.log and date shows me another time 75 seconds behind the correct time from the dom0 domain. All running domU domains have the same incorrect time. On one domU I have setup a ntpd and set /proc/sys/xen/independent_wallclock to 1. At startup of ntp following appears in syslog FATAL: Could not load /lib/modules/2.6.12.6-xenU/modules.dep: No such fi le or directory I have a kernel without any modules in the domU domain. After a few minutes the domU domain have the correct time from the ntp server. Now I set /proc/sys/xen/independent_wallclock to 0. After 12 hours following appears: time on dom0 still correct time on domU with ntpd is 10 seconds behind the correct time time on the other domU is 85 seconds behind the correct time. So time sync between the dom0 and domU domains seems not working. Have you any hint how I can solve this problem? Thanks -- Olaf Berg IMA Gesellschaft für Informationsmanagement mbH Bergmannstr. 32 44809 Bochum eMail: olaf.berg@imagmbh.de Tel.: +49 234 / 516990-45 Fax: +49 234 / 516990-99 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Stephan Austermühle
2006-Apr-13 12:19 UTC
Re: [Xen-users] time drift between domU and dom0
Hi Olaf!> So time sync between the dom0 and domU domains seems not working. > Have you any hint how I can solve this problem?As far as I understand time synchronization (my mail regarding this topic is not yet answered) your setup works as designed. For my understanding the domU gets the time from dom0 at startup like a native system gets it from the hardware clock. Once this is done the guest kernel maintains its own system clock. Thus you need a ntpd in all of your domUs. If your guests complain about missing modules or missing dependencies then you should either install them or recompile your kernel to include the missing features. I''ve a setup similar to yours (dom0 synchronizes against a reference clock, domUs synchronize against dom0 using ntpd) working without problems. Stephan _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users