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

Daniel Havey dhavey at yahoo.com
Wed Sep 22 23:09:46 UTC 2010


I had a feeling it would come down to this.  Now the mystery has been solved.  The ntpdate script is much faster than ntpd.  That is why it is recommended for use rather than ntpd.  I agree with them.  A day or even 10 hours is totally unacceptable.  This is an emulab like testbed.  We bring nodes into experiments, wipe them out, re-configure, and reboot frequently.  Even 10 minutes, would be extremely annoying.  So if I reboot my nodes 6 times in a day then I must spend an hour waiting for ntpd to do it's voodoo?

My UCSB webserver is where I would post a graph if I wanted to put a link here to the graph (which I don't anymore).

--- On Wed, 9/22/10, unruh <unruh at wormhole.physics.ubc.ca> wrote:

> From: unruh <unruh at wormhole.physics.ubc.ca>
> Subject: Re: [ntp:questions] Why does ntp keep changing my conf file?
> To: questions at lists.ntp.org
> Date: Wednesday, September 22, 2010, 3:02 PM
> 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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