[ntp:questions] ntpd -x option

Unruh unruh-spam at physics.ubc.ca
Wed Mar 11 16:11:58 UTC 2009

Matthias Fuchs <matthias.fuchs at esd-electronics.com> writes:


>I am trying to understand ntpd's -x option. From the ntpd documentation
>I expect ntpd to adjust the (system-)time in all situations when -x
>is used. The only exception I see is when the system time is totally wrong
>(more than 1000s) ntpd will see this as an error and exit. This can be
>avoided through the "tinker panic 0" configuration.


>But now, when I start ntpd with the -x option and an offset of
>about 30s before ntpd is started, I get error messages like this

>        frequency error 557 PPM exceeds tolerance 500 PPM

>Also there seems to be not regulation at all and ntptime reports

>~# ntptime
>ntp_gettime() returns code 5 (ERROR)
>  time cd624627.39886000  Wed, Mar 11 2009 15:16:07.224, (.224737),
>  maximum error 993296 us, estimated error 16 us
>ntp_adjtime() returns code 5 (ERROR)
>  modes 0x0 (),
>  offset 0.000 us, frequency 0.000 ppm, interval 1 s,
>  maximum error 993296 us, estimated error 16 us,
>  status 0x40 (UNSYNC),
>  time constant 4, precision 1.000 us, tolerance 512 ppm,

>I am using two remote stratum 1 NTP servers for these tests.

>So is there any way to make ntpd _adjust_ the time in all situations?
>I am aware of the maximum adjustment of 500ppm (0.5ms/s). I would be lucky
>if ntpd could adjust the above offset (30s) in a day or so.

>I not want ntpd to step my system time! Not even once during initial

Do not use ntp. Use chrony instead. It has a far far faster adjustment.
However, it only runs on Linux.

>ntpd is version ntpd 4.2.2p4 at 1.1585-o on Debian Etch for PowerPC.

>I hope somebody can give me some hints.


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