[ntp:questions] Why does ntp keep changing my conf file?

unruh unruh at wormhole.physics.ubc.ca
Wed Sep 22 22:02:44 UTC 2010


On 2010-09-22, Daniel Havey <dhavey at yahoo.com> wrote:
> I guess I can't show the graph, since I cannot reach my UCSB webserver from here.

What does your web server have to do with it?

>
> [dhavey at node1 ~/MANET]$ ntpq -npc rv
>      remote           refid      st t when poll reach   delay   offset  jitter
>==============================================================================
> *192.168.1.10    130.221.24.100   2 u   23  256  377    0.168   17.224   1.515
> assID=0 status=0644 leap_none, sync_ntp, 4 events, event_peer/strat_chg,
> version="ntpd 4.2.2p1 at 1.1570-o Sat Dec 19 00:58:16 UTC 2009 (1)",
> processor="i686", system="Linux/2.6.18-164.11.1.el5", leap=00,
> stratum=3, precision=-20, rootdelay=4.211, rootdispersion=84.326,
> peer=53715, refid=192.168.1.10,
> reftime=d044e85b.b36d9436  Wed, Sep 22 2010 13:40:59.700, poll=8,
> clock=d044eb73.1a72e7e7  Wed, Sep 22 2010 13:54:11.103, state=4,
> offset=17.224, frequency=135.852, jitter=1.638, noise=7.224,
> stability=6.210, tai=0
>
> It's going the wrong way.  It should be reducing the offset and it is making it worse.
>

No, it should not. The offset will increase because it has the wrong
value for the frequency drift. Eventually it will converge to the right
value and the offset will then decreease until you have offsets of about
.1ms.
NOte that if you used chrony, the process would take about 10 min. With
ntp it will take 5-10 hours. It is a feature.



>
>
> --- On Wed, 9/22/10, Chuck Swiger <cswiger at mac.com> wrote:
>
>> From: Chuck Swiger <cswiger at mac.com>
>> Subject: Re: [ntp:questions] Why does ntp keep changing my conf file?
>> To: dhavey at yahoo.com
>> Cc: questions at lists.ntp.org
>> Date: Wednesday, September 22, 2010, 1:36 PM
>> On Sep 22, 2010, at 1:18 PM, Daniel
>> Havey wrote:
>> > The bloody thing made it worse!? Look at the
>> graph.? It was doing just fine at 0.002147 second
>> offset, then I started ntpd and look what it does.?
>> This is definitely not very good for a testbed.
>> 
>> What graph?? You'll need to mail out a link, since
>> most mailing lists eat attachments (they've got to be fed
>> somehow, I guess)....
>> 
>> Also, ntpq output like the following is helpful for
>> debugging issues:
>> 
>> % ntpq -npc rv
>> ? ???remote? ? ? ?
>> ???refid? ? ? st t when poll
>> reach???delay???offset?
>> jitter
>> ==============================================================================
>> -66.250.45.2? ???192.5.41.40?
>> ? ? 2 u???22? 512?
>> 377???26.389? ?
>> 7.667???0.498
>> *18.26.4.105? ???.GPS.? ?
>> ? ? ? ? 1 u???54?
>> 512?
>> 377???24.070???-0.925???0.458
>> +128.59.59.177???128.59.39.48?
>> ???2 u???42? 512?
>> 377???26.898? ?
>> 0.408???0.033
>> +17.254.0.27? ???17.72.133.54?
>> ???2 u???48? 512?
>> 377???54.681? ?
>> 0.587???0.106
>>  24.103.228.242? 18.26.4.105? ? ? 2
>> u???37? 512?
>> 377???33.338???-2.185???0.726
>> associd=0 status=0644 leap_none, sync_ntp, 4 events,
>> freq_mode,
>> version="ntpd 4.2.4p5-a Mon Sep 20 14:30:32 EDT 2010 (1)",
>> processor="i386", system="FreeBSD/6.4-STABLE", leap=00,
>> stratum=2,
>> precision=-19, rootdelay=24.070, rootdispersion=26.037,
>> peer=43124,
>> refid=18.26.4.105,
>> reftime=d044e485.9adbf554? Wed, Sep 22 2010
>> 16:24:37.604, poll=9,
>> clock=d044e6bd.18405690? Wed, Sep 22 2010
>> 16:34:05.094, state=4,
>> offset=-0.239, frequency=19.470, jitter=1.043,
>> noise=0.380,
>> stability=0.019, tai=0
>> 
>> Regards,
>> -- 
>> -Chuck
>> 
>> 
>
>
>       =




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