[time-nuts] Recommendations for NTP server

Geoff Powell geoff at g8kbz.demon.co.uk
Sun Apr 23 17:00:47 EDT 2006

I've just started getting interested in precision timekeeping - if you
can call an offset from UTC that is measured in units of milliseconds

My current timeserver is a Buffalo Linkstation, patched to run Debian
Stable, and slaved via 2MBit ADSL to my ISPs Stratum 2 timeserver, using
NTP V4.2.0, from the Debian Stable repository. I'm seeing offsets in the
low millisecond range, but with frequent excursions up to 10 to 20
millisec or more. These large spikes in the offset curve are definitely
correlated with large data transfers down from the Internet. Look at
http://www.g8kbz.demon.co.uk/mrtg.html for a sample plot, derived by
MRTG, and updated daily at midnight local time.

There seems to be no prospect of mitigating these offset spikes without
taking further steps, and I intend to install a new timeserver, probably
using a Soekris NET4801 and a Garmin GPS18LVC. I hope to effect a 3
order of magnitude improvement in observed offset, and more would be
appreciated - I've already been bitten by the precision bug.

So my question is - should I continue with Debian Stable, or would
OpenBSD be better for sub-microsecond accuracy? Indeed, is sub-
microsecond offset achievable with this hardware? GPSDOs and Rb or Cs
standards are not yet practical politics.

Thanks in advance for any tips,
Geoff Powell

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