[ntp:questions] chrony as a server

Paul tik-tok at bodosom.net
Tue Feb 24 19:40:41 UTC 2015


On Tue, Feb 24, 2015 at 1:14 PM, Charles Swiger <cswiger at mac.com> wrote:

> On Feb 23, 2015, at 11:57 PM, David Woolley <david at ex.djwhome.demon.invalid>
> wrote:
> > On 23/02/15 21:23, William Unruh wrote:
> >> manual corrections are probably good to 1 sec.
> >
> > It's a long time since I did this, but 200ms is more like it
>
> However, if you time things with a rhythm you can get to ~50 ms or better
>

While these performance anecdotes are interesting they (starting with
unruh at invalid) are all anecdotes.  I didn't mention research and real
numbers by accident.

The underlying assertion is that the chrony method offers some value and is
superior to NTPd.  So I'd like something more than hand-waving regarding
the performance and if it's better than just setting the clock once and a
while I'll write something to create a drift file based on the operator
listening to USNO ticks (or Emerald Time if you have it) and pressing
return at the right time.

Someone else can do a version that uses a microphone to listen to the ticks
-- a stone-age ACTS driver.

With regard to return on investment and underlying arguments about
"advantages".  I don't buy the "Well someone may want to do this so it's
worthwhile" argument.  Doing something foolish or stupid doesn't make
Chrony better than NTPd.

Or to put it another way -- NTPd is about precise time transfer and it
protects you from falsetickers like your wristwatch.


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