[ntp:questions] Re: ajusting clock in steps

Richard B. Gilbert rgilbert88 at comcast.net
Tue Apr 25 14:09:53 UTC 2006

Marcus König wrote:

> Hello NG,
> i compiled ntp version 4.2.0 on AIX 5.1 with a hopf-clock. After that i
> compiled this version on AIX 5.2 run as Client for the 5.1. My problem
> ist that after a time the clocks are synchronized in one step.
> How can I configure the client that he sets the time in steps like 1
> second in one hour?
> thanks for answering.
> regards marcus.

Please see the the ntpd documentation at 
http://www.eecis.udel.edu/~mills/ntp/html/ntpd.html or it's also 
available in your ntp-4.2.0.html directory.

In brief, ntpd slews the clock to correct errors less than 128 
milliseconds or steps the clock if the error is greater.   You can start 
ntpd with the -x option which will change the threshold to 600 seconds. 
  Doing so, without first setting the clock, will require one full day 
to correct an error of 42 seconds!!

An error large enough to cause ntpd to step the clock is usually an 
indication of a problem somewhere.

Best practice is to start ntpd with the -g option which causes ntpd to 
set the clock on a one time basis.   Do so before starting any 
application that needs either the correct time or monotonically 
increasing time.

Once started with the correct time, ntpd should be able to maintain the 
local clock within 5-10 milliseconds of the correct time using internet 
servers or within 1-2 milliseconds using a server on the LAN.

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