Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have a low cost server running Debian Squeeze stable, using the Xen hyperviser. After a very long uptime the clocks of the unprivileged domains will deviate. Restarting the domains will not fix the clocks. I have tried using hwclock to reset the clock, but new domains will still have a clock that is a few minutes off.

I want new domains to have an accurate clock without resetting the whole server. Is there a way to fix the clocks without needing to run ntpd/ntpclient in the unprivileged domains?

Running Xen 4.0.1 provided by Debian Sqeeze
Domain 0 Kernel is Linux 3.2.0 from Debian backports

share|improve this question

Use xen.independent_wallclock=1 on dom0. Other workarounds can be found at

share|improve this answer
error: "xen.independent_wallclock" is an unknown key. Also that site talks about "jiffies" as a clock source, but I only see xen and tsc. – Lunatic Experimentalist Sep 7 '12 at 23:19
Sysctl variable xen.independent_wallclock is available only in dom0 domain, so you need to login to your carrier server (dom0) and apply it. – lik Sep 8 '12 at 0:36
That unknown key error was from dom0. – Lunatic Experimentalist Sep 8 '12 at 0:42

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.