[ntp:questions] NTP client configuration

Richard B. Gilbert rgilbert88 at comcast.net
Thu Sep 27 20:05:01 UTC 2012

On 9/27/2012 2:59 PM, Benjamin CABUT wrote:
> Hello,
> I don't car in my application to have the correct UTC time.
> What I care is that all my computers share exactly the same time.
> Our application is not connected to internet.
> So only time I can use as a reference is local clock of one computer.

It's difficult to get multiple devices to keep a common time without a
stable reference clock. I'd suggest using a GPS timing receiver.  It 
will give you a rock solid one second per second beat that most 
computers can synchronize with.

NTPD needs about ten hours to synchronize its host down to the 
nano-second level.  Once synchronized it should stay synchronized.

If you need to turn everything off at 5:00 PM and turn it on again
at 9:00 AM, NTP is a poor choice.

> I can realy tell you that my client is not sync some times!
> it happen in 2 ways:
> -> when I start my computers, it need arround 5 minutes to be sync, it
> is a problem for me
> -> when one computer has heavy operation to do, then ntp client desync
> and I have offset that can be 2 seconds, and stay like this during
> sereval minutes.
> so It realy need a long time to ntp client to detect the big desync.
> I do not want to rewrite ntp.
> ntpq gives the offset between clock of client and clock of server.
> As you say the best way for me is that ntp is working perfectly, but it
> is not the case.
> I don't know how to improve this by configuration.
> So I was just wondering if I could get the offset in my software to
> solve my problem...
> Regards.

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