[ntp:questions] ntpd: time reset problem

David Lord snews at lordynet.org
Mon Sep 14 14:12:25 UTC 2009


Frank Elsner wrote:
> Steve Kostecke wrote:
>> On 2009-09-14, Frank Elsner <Elsner at tubIT.TU-Berlin.DE> wrote:
>>
>>> The relevant lines read:
>>>
>>> server times.tubit.tu-berlin.de       minpoll 6 maxpoll 8
>>> server ntps1-0.cs.tu-berlin.de        minpoll 6 maxpoll 8
>>> server ntps1-1.cs.tu-berlin.de        minpoll 6 maxpoll 8
>>> server zeit.fu-berlin.de              minpoll 6 maxpoll 8
>>> server ntp1.ptb.de                    minpoll 6 maxpoll 8
>>> server ntp2.ptb.de                    minpoll 6 maxpoll 8
>>> server ntp1.rz.uni-konstanz.de        minpoll 6 maxpoll 8
>>> server rustime01.rus.uni-stuttgart.de minpoll 6 maxpoll 8
>>
>> Why are you changing the minpoll / maxpoll ?
> 
> Copied from some example.
> 
>> Please try again without the minpoll / maxpoll modifiers.
> 
> Ok, I will remove the minpoll / maxpoll modifiers.
> 
>>> # Undisciplined Local Clock. This is a fake driver intended for backup
>>> # and when no outside source of synchronized time is available.
>>> server  127.127.1.0     # local clock
>>> fudge   127.127.1.0 stratum 10
>>
>> The Undisciplined Local Clock is only needed if this ntpd must be able
>> to serve time to others when no real time sources are available. It
>> should not be considered a backup for a "leaf-node" system.
>>
>> Do you have a driftfile line?
> 
> Yes, this one:
>                  116.833

?

I'll guess that's content of your drift file rather than
location specified in ntp.conf.

OT you also have rather a lot of sources specified and if
just for a single box it seems a bit excessive and could
be trimmed to four or five (I'd also guess some of those
eight get same refid).

What's output from commands "ntpq -c lpeers" and
"ntpdc -c loopinfo"?

I've just been trying mobile broadband on a high latency
connection and it was too much for ntpd at 1-2 sec average
and 150ms best to 10 sec/timeout at worst :-)

Then this weekend after reconfigured to use "burst" in server
lines and initial ntpd -q, it's synced in a few minutes but
pinging various sites now shows the very high latency has gone
away (all < 300ms), still not very good but good enough.

David




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