[ntp:questions] Time reset

Richard B. Gilbert rgilbert88 at comcast.net
Sun Apr 6 04:23:09 UTC 2008


Danny Mayer wrote:
> Hal Murray wrote:
> 
>>>The ntp log file shows when NTP steps the time. But then the potential harm
>>>is already done. Especially if the time moves backward, our server might
>>>have serious trouble. Is there a log event which indicates that the time is
>>>going to be reset in order to enable us to take appropriate action before
>>>the actual reset?
>>
>>I don't know of any way to get advanced warning when ntpd is about to
>>step the time.
>>
> 
> 
> You cannot have advanced warning before stepping. It doesn't know until 
> it decides it needs to do it.
> 
> 
>>There are command line switches to prevent stepping and to allow
>>one step at startup time.
>>
> 
> 
> Yes. You can use -x to slew always.
> 
> Danny

And if the clock is off by many hours, it could take days or weeks to 
synchronize.

Use the -g option when you start ntpd.  This will set the clock once 
only.  IF your system is working properly, ntpd should be able to 
synchronize the clock fairly quickly and to keep it synchronized as long 
as it has a good source of time.

If ntpd steps the time AFTER startup, you have a serious problem 
somewhere.  IMHO the best way to deal with such stepping is to find out 
what's broken that makes stepping necessary and fix it!




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