[ntp:questions] Ignore one server except in extreme conditions?

Dave Hart hart at ntp.org
Thu Nov 17 06:43:29 UTC 2011


On Thu, Nov 17, 2011 at 06:35, A C <agcarver+ntp at acarver.net> wrote:
> On 11/16/2011 16:09, Dave Hart wrote:
>> You don't have to use two separate drivers for NMEA and PPS, even with
>> the signals coming in on different serial ports.  At least in 4.2.7,
>> the NMEA driver tries /dev/gpsppsX for PPSAPI before falling back to
>> using the same port as for NMEA, /dev/gpsX.  In this configuration,
>> you don't need to mark any peers as prefer, which I much prefer
>> compared to using ATOM and marking all your network peers and NMEA
>> prefer, because prefer has profound effects on mitigation which are
>> tricky to wrap your head around.
>>
>> I encourage you to try a recent 4.2.7 ntpd with only the NMEA driver
>> with its PPS handling enabled
>
> I compiled the latest development version 4.2.7p234.  The NMEA driver does
> not pick up /dev/gpspps for whatever reason even if I have the symlink
> defined.

Did you try /dev/gpspps0, assuming server 127.127.20.0?  Did you
"fudge 127.127.20.0 flag1 1" to enable NMEA's PPSAPI support?

Cheers,
Dave Hart


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