[ntp:questions] NTP is working fine but time difference doesn't decrease.

David Woolley david at djwhome.demon.co.uk
Wed Apr 18 22:29:30 UTC 2007

In article <1176885032.540309.233710 at b75g2000hsg.googlegroups.com>,
kaleem177 at gmail.com wrote:

> We have a machine which is running NTP version 4 and it's in sync with
> its time server (a '*' appears in the output of ntpq -p; as we know
> the server marked * is the one which is chosen for synchronization).

A combination of those with * and + are used for synchronisation.

> Now the problem
> is that even if the machine is synchronizing with its time server all
> the time, the time difference between the two doesn't decrease. The
> difference is around 2 min and it's been like this for one month or
> so. I expect the machines to be within a few seconds of each other.

ntpd is in difficulties if the times differ by more than 128ms.

Have you or your OS vendor used any unusual options?  Have you been 
overzealous with restrict?  What does syslog say?

You should have observed time steps with a standard configuration.  If
the system does step and then immediately steps back to 2 minutes, you 
have another time synchronisation application running, with a different
idea of the time.

> The only reason I can think of is that the clock crystal is behaving
> wildly.

This would only be a factor if the system was configured not to step at
all and the clock error was exactly 500ms.  With no clock error, and
slew only, the clock should recover 46 seconds per day.

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