Mailinglist Archive: opensuse (1470 mails)

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[opensuse] Time server clients
  • From: Roger Oberholtzer <roger.oberholtzer@xxxxxxxxx>
  • Date: Fri, 26 Feb 2016 14:01:28 +0100
  • Message-id: <CANkOqwN6=jmPGDF8fwqVg6+CcH0fZTVVtOz2ueEKtdL62GB_Aw@mail.gmail.com>
We have been playing with high precision time in our
non-internet-attached openSUSE systems. We use a high-end GPS receiver
that provides a PPS signal on a serial port. Using gpsd and chrony, we
have our openSUSE systems coming up as a Stratum One NTP server quite
reliably after system boot. No humans. Just a nice ICON in the system
tray that turns green when time is syncd.

The goal was to have the system clock as accurate as possible so we
can locate positions with high accuracy. The NTP was an afterthought
(chrony, which is maintaining the system clock also can act as an NTP
server): why not try to make other system components share this time
synchronization? For example, there is a device that runs some
embedded MS Windows. It timestamps it's data. Let's set it's clock as
well.

Initially, we thought that chrony on openSUSE had a problem. We just
did not feel that the times reported by this Windows device looked so
very accurate. And it was inconsistent. Sometimes it was decent
accuracy. But sometimes not. Part of our method was to set up the
Windows NTP client as an NTP source back in to the openSUSE machine
(but not actually use the time - just report it). And we could see the
unexpected difference in times. Damn. chrony has a problem.
OpenSource, you know...

Dig dig. Hunt hunt. Then...

https://blogs.technet.microsoft.com/askds/2007/10/23/high-accuracy-w32time-requirements/

Sigh.

Has anyone else been effected by this problem? I understand that for
most it is not a problem. But I find it incredible that when talking
to a Stratum One server on a private network, decent time cannot be
maintained by the Windows time service.

If anyone else has been effected by this, was a solution found? There
is a link to third-party solutions. We really do not want to rework
someone else's box. If there is a better option.


--
Roger Oberholtzer
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