[ntp:questions] Odd (mis)behavior when reference clock fails

David Woolley david at ex.djwhome.demon.co.uk.invalid
Fri Sep 19 07:08:38 UTC 2008


Firstly, the original of this thread root has been demimed out of 
existence by the mail to news gateway.  I thought the official line is 
that what went out to the mailing list was the same that which went to 
the newsgroup.

All that remains is:

 >  [demime 1.01d removed an attachment of type multipart/signed]

This can be confirmed on Google groups.

Rob Neal wrote:
> On Tue, 16 Sep 2008, Kevin Oberman wrote:
> 
>> We have a fairly large "mesh" of NTP servers spread across the
>> US. Almost all have PPS reference clocks and are quite
>> accurate. Recently one of the reference clocks located across the county
>> seems to have failed. Such is life.
>>
>> The problem is that the system's time started drifting and eventually
>> became far enough out of sync with the mesh to be marked as a bad
>> ticker.
>>
>> The only way I could get the clock to slew or step the time was to edit
>> the configuration and comment out the reference clock and PPS. It looks
>> like the system will only use the time from a reference clock when and if
>> the clock is configured, even if it can't be read.

That should not be the case.  Are you sure that the clock had stopped 
responding and stopped providing a PPS signal?  If it is still providing 
PPS this will be used, and other clocks only to resolve the second 
ambiguity.

Another thing to check of is whether there was a local clock configured. 
  This can compromise fault recovery.

What we really need is the contents of the configuration file and the 
result of running ntpq peers.  We may then ask you for the result of 
running ntpq rv on the system and on each of its associations.

Please reply in plain text, or directly to the newsgroup, otherwise 
neither I nor the originator of NTP will see your reply.




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