[ntp:questions] Re: OT: Linux and NTP

Ulrich Windl Ulrich.Windl at RZ.Uni-Regensburg.DE
Thu Nov 27 12:40:05 UTC 2003


k.tragant at firemail.de (Kurt Tragant) writes:

> Hello Group,
> 
> I've setup two NTP servers for the network. These two servers
> synchronize time with two public NTP servers. The other computers
> synchronize time with my NTP servers. Everything works fine but my two
> NTP servers have different times (21 seconds difference).
> 
> Server 1:
> # /sbin/hwclock ; date
> Mit 26 Nov 2003 18:16:52 CET  -0.560965 Sekunden
> Mit Nov 26 18:16:30 CET 2003

The CMOS clock hasn't been set from the system (software) clock. This
is a Linux issue. See  http://www.ntp.org/ntpfaq/NTP-s-trouble.htm#AEN5044


> # /usr/sbin/ntpq -p
>      remote           refid      st t when poll reach   delay   offset
>  jitter
> ==============================================================================
>  LOCAL(0)        LOCAL(0)        10 l   23   64  377    0.000    0.000
>   0.015
> +chronos.zedat.f .GPS.            1 u  227  512  377   15.887  -74.098
>  12.250
> *ntp0-rz.rrze.un .GPS.            1 u  168  512  377   25.028  -70.056
>  11.954
> 
> Server 2:
> # /sbin/hwclock ; date
> Mit 26 Nov 2003 18:16:51 CET  0.333037 Sekunden
> Mit Nov 26 18:16:51 CET 2003
> # /usr/sbin/ntpq -p
>      remote           refid      st t when poll reach   delay   offset
>  jitter
> ==============================================================================
>  LOCAL(0)        LOCAL(0)        10 l   43   64  377    0.000    0.000
>   0.000
> *chronos.zedat.f .GPS.            1 u   44   64  277   17.101  -70.165
>   2.183
> +ntp0-rz.rrze.un .GPS.            1 u   62   64  377   25.312  -60.754
>   2.702
> 
> It seems that hardware time is correct but NTP uses software time,
> doesn't it? If I fetch the time manually with ntpdate on both servers,
> there is also a time difference of 21 seconds.
> Any ideas? Thanks in advance.

Understand that UNIX/Linux time is sofware time. CMOS clock is just
some extra hardware.

Regards,
Ulrich

> 
> Regards
> Kurt Tragant



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