[ntp:questions] Timekeeping on Windows 2008r2 VM on Linux QEMU/KVM

Martin Burnicki martin.burnicki at meinberg.de
Wed Jan 21 13:28:31 UTC 2015


Sander Smeenk schrieb:
> Quoting Harlan Stenn (stenn at ntp.org):
>
>> The time values are in milliseconds, not seconds.
>
> Yes, that's right, my bad. :(
> But that's not the point, really.
>
> The offets keep increasing and increasing up to the point
> where ntpd.exe drops all the servers and sync_ntp flag is lost.
>
> The exact same ntp servers are used on Linux VMs running on the same
> QEMU/KVM host and they do not show the increasing offsets and jitter
> values.
>
> Something is awry and i can't figure out what, where and why. :/

Windows isn't a very good timekeeper anyway.

I don't find it surprising that Linux VMs are behaving nicer. Linux 
timekeeping is more stable anyway, and since QEMU/KVM is also based on 
Linux I would expect they work better together than Windows on Linux.

I see you already run ntpd v4.2.8 in your VM, which already contains a 
workaround for another deficiency in Windows, where small tick 
adjustments are not handled correctly.

Martin
-- 
Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont
Germany



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