[ntp:questions] What level of timesynch error is typical onWinXP?

Richard B. Gilbert rgilbert88 at comcast.net
Fri Oct 22 13:54:27 UTC 2010


On 10/22/2010 6:39 AM, David J Taylor wrote:
> "Dave Hart" <davehart at gmail.com> wrote in message
> news:AANLkTik1Pda81Pqmx2JNtgV9AYS6h7HahT3+ZELf+Yn=@mail.gmail.com...
> []
>> No new settings required. You might have a hard time picking out the
>> difference using 5-minute samples of mrtg and the hardcoded Y axis.
>> Looking at loopstats graphs, I would expect you to see little
>> overshoot or ringing from the initial offset correction.
>>
>> Cheers,
>> Dave Hart
>
> Thanks, Dave. I may be missing something here, but it seems to me that
> 4.2.7p58 still takes a number of hours to reach the accuracy limits
> where thermal effects dominate. It's that which matters to me, rather
> than something in the first few minutes. I agree the graphs would not
> show such short time-scale initial disturbances.

AFAIK, *all* versions of NTPD require several hours to reach a stable 
state and a close approximation to the correct time.  NTPD was designed 
for operation 24x365.  Every time you shut down you will encounter a 
multi-hour settling period.  The time will be *close* to correct within 
thirty minutes or so; getting within microseconds takes a good deal longer!

The solution is obvious: don't shut down! If you are in a situation 
where only 9-5, M-F operation is possible and microsecond accuracy is 
required, NTPD is probably the wrong tool for the job.  See CHRONY.  Its 
design goals are different and include fast startup.




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