[ntp:questions] Re: ntpdc 'sysinfo' output inconsistent with ntpq-p output

Richard B. Gilbert rgilbert88 at comcast.net
Mon Jul 24 16:17:10 UTC 2006


Tripathi, Anurag wrote:

> Here is ntpq -crv output: 
> ----
> assID=0 status=c624 sync_alarm, sync_ntp, 2 events,
> event_peer/strat_chg,
> version="ntpd 4.2.0a"?, processor="i686",
> system="Linux/2.6.13.4-ws-symbol", leap=11, stratum=16, precision=-20,
> rootdelay=0.000, rootdispersion=10.965, peer=17460, refid=INIT,
> reftime=00000000.00000000  Thu, Feb  7 2036 11:58:16.000, poll=6,
> clock=0xc86f5eb1.a257a786, state=3, offset=9.887, frequency=0.000,
> noise=3.628, jitter=2.328, stability=0.000
> ------
> 
> As suggested earlier after 30mins 'ntpdc sysinfo' starts showing the
> correct information i.e. 'synched'. 
> 
> But isn't 30mins too long a delay for show an information which ntpq
> declares within seconds? 
> 
> More importantly is there anyway I can reduce/minimize this time lag?
> (some keyword or configuration?)
> 
> This would be helpful!
> 
> Regards,
> Anurag
> 
> Other requested info:
> Ntpq version: "ntpq 4.2.0a at 1.1196-r Thu Mar 16 13:07:10 IST 2006 (1)"
> Ntpdc version: "ntpdc 4.2.0a at 1.1196-r Thu Mar 16 13:07:07 IST 2006 (1)"
> 

Ntpd can select a synchronization source very quickly, especially if you 
use "iburst" on your server lines in ntp.conf.

It can take far longer for ntpd to bring your local clock into close 
agreement with UTC where "close" means < 20 milliseconds.

You can reduce the time required by using the -g option when you start 
ntpd.  That will cause ntpd to set the clock unconditionally to 
something close to the correct time.  Ntpd will still require some time 
to adjust the speed of your local clock so that it neither gains nor 
loses time.

A "cold" start (no drift file) of ntpd can take many hours to reach a 
stable state with both the correct time and the correct frequency 
adjustment.  A warm start is faster but can still require twenty or 
thirty minutes to beat your local clock into submission. :-)

You can probably see similar results from ntpq and ntpdc in far less 
time than thirty minutes.  As nearly as we could tell, you had allowed 
less than two minutes since startup.




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