[CentOS] Date drift and ntpd

Markus Falb markus.falb at fasel.at
Fri Aug 13 15:21:04 UTC 2010


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On 13/08/2010 23:06, Jerry Franz wrote:
> On 8/12/2010 8:03 PM, Les Mikesell wrote:
>> Warren Young wrote:
>>>
>>> The strategy I recommended is based on the fact that its worst case
>>> behavior (a small negative jump every hour) is not a problem for me.  If
>>> it is a problem for your application, you need a different design.
>>
>> It's a bad idea in the general case.  If you have scheduled jobs, ntpdate may
>> jump the clock enough to miss the trigger or run them twice, where ntpd always
>> tries to move the clock fractional seconds at a time so as not to let that
>> happen.   Plus, ntpdate does no sanity check at all - if the clock source is
>> badly off, the client will follow blindly even if it goes to the wrong century.
>>
> 
> Whereas ntpd will simply quietly fail to sync at all if it is more than 
> a few minutes off. ;)

I believe it will not fail if you tell it to
tinker panic 0

Regards, Markus
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