[ntp:questions] confusing clock selection...

Richard B. Gilbert rgilbert88 at comcast.net
Fri Jul 8 15:53:25 UTC 2011


On 7/8/2011 10:38 AM, Florian Heigl wrote:
> Hi,
>
> I'm doing some testing of the ntp config I made and don't really
> understand what just happened.
> Primarly I'm looking at two ntp servers and one clock out of a larger
> setup.
> NTP is quite critical so I've already done some head-scratching to
> come to this setup.
>
> Setup on "ntp01":
> server meinberg1
> server meinberg2 prefer
> server meinberg3
> server meinberg4
> peer ntp02 iburst # this line reads ntp01 on the other server
>
> # local fallback clock
> server 127.127.1.0
> fudge 127.127.1.0 stratum 10
>
> driftfile /var/lib/ntp/drift
>
>
> Note about the local clock: Lik
>
>
> Right now only Meinberg3 is online, and, to make things more
> interesting, I unplugged it's GPS cable. It kept at stratum 1/2 for a
> long duration and now went dpwn to stratum 3 local source.
>
> I would have hoped both "ntp" servers would still use meinberg3,
> instead they decided to pick their local clock.
>
>       remote           refid      st t when poll reach   delay
> offset  jitter
> ==============================================================================
>   meinberg1          .INIT.          16 u    -   64    0    0.000
> 0.000   0.000
>   meinberg2          .INIT.          16 u    -   64    0    0.000
> 0.000   0.000
>   meinberg3          LOCAL(0)         3 u   34   64    7    0.192
> -1531.5   5.156
>   meinberg4          .INIT.          16 u    -   64    0    0.000
> 0.000   0.000
>   ntp02        LOCAL(0)        11 u   24   64   17    0.216  -1529.3
> 7.325
> *LOCAL(0)        .LOCL.          10 l   30   64   17    0.000
> 0.000   0.001
>
>
>
> I really do love working with NTP, just right now I don't understand
> why it does what it's doing (even if it may just be what I configured
> into it, right?

I'd suggest a little more diversity in servers.  Four Meinberg servers, 
presumably located at the same site, could leave you with NO servers if 
the Meinberg site went down or if you lost connectivity to the site.





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