[ntp:questions] ntpd losing sync

Harlan Stenn stenn at ntp.org
Sat Feb 4 09:11:36 UTC 2012


A C wrote:

> Here's the current configuration for version 4.2.7p236:
> 
> server          0.us.pool.ntp.org minpoll 9 iburst
> server          1.us.pool.ntp.org minpoll 9 iburst
> server          0.north-america.pool.ntp.org minpoll 9 iburst

You might try replacing the above 3 lines with:

 pool us.pool.ntp.org minpoll 9 iburst

I do not remember offhand if iburst is supported for the "pool"
directive but give it a shot.

> server ntp1.gatech.edu prefer minpoll 9

Is this server close enough that you want to "prefer" it?

> server rolex.usg.edu minpoll 9
> server  127.127.22.0  minpoll 2 maxpoll 4
> fudge   127.127.22.0  time1 +0.000 flag2 1 flag3 1 refid PPS

0.0 is the default for time1.

flag2 1 means PPS capture on the falling (clear) edge of the pulse.

flag3 1 enables the kernel PPS discipline.

I haven't been following this thread - what OS are you using?

> server  127.127.28.0  minpoll 7 noselect
> fudge   127.127.28.0  time1 -0.6 refid GPSD

OK, GPSD via the shared memory driver, and "noselect".  Nasty jitter on
this one...

> The peer list after waiting about a day from the initial system upset:
> 
>     remote           refid     st t when poll reach  delay  offset  jitter
> ==========================================================================
> x127.127.22.0   .PPS.           0 l    -   16  377   0.000 -465.49  355.933
>  127.127.28.0   .GPSD.          0 l    -  128  377   0.000 -208986  2833.87
>  207.7.148.214  216.218.254.202 2 u    -  512  377 1045.07 -209713 11784.0
>  72.14.179.211  127.67.113.92   2 u    -  512  377 1029.80 -201710  6559.37
>  173.255.224.22 128.4.1.1       2 u  245  512  377 919.628 -202629  7684.05
>  130.207.165.28 130.207.244.240 2 u    -  512  377 994.543 -204125  7778.28
>  131.144.4.10   65.212.71.102   2 u   23  512  377 1000.21 -203648  7687.63
> 
> Note that the offset for PPS is swinging wildly, not exactly visible in 
> this static snapshot.

What's with the delay numbers?  Are you on a network link that is
saturating?

H


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