Fedora 7: a problem with ntp ?

Nigel Henry cave.dnb at tiscali.fr
Sat Sep 8 23:12:18 UTC 2007


On Saturday 08 September 2007 21:44, Andrew Junev wrote:
> Saturday, September 8, 2007, 5:42:37 PM, you wrote:
> > Dumb question - what kernel are the FC6 systems running, and what
> > kernel is the F7 system running? Could there be a problem on your
> > system with the new "tickless" kernels and ntpd?
>
> Fedora Core 6 uses 2.6.20-1.2962.fc6
> Fedora 7 uses 2.6.22.4-65.fc7
>
> I also thought the kernel might be a problem. But for some reason
> noone else has it. It makes me think it's something with the
> configuration. But in fact it's a clean install of Fedora 7 with all
> the option set to its default values (except for the firewall and
> selinux which are disabled) and just ntp turned on...
>
> Can it be a problem with my hardware (I mean motherboard)? Is there a
> way to trace it?
>
> Thanks!

I've spent quite a bit of time looking into this problem today, and there 
appears to be some sort of problem with ntp on Fedora 7. My Fedora 7 is on a 
machine that gets it's time from my other machine, which gets it's time from 
the Internet. i've run ntpq> pe every few minutes, and the F7 machine gets 
the time synchronized from the other machine, but never polls less than every 
64 secs. it then loses the synch, and starts afresh. It eventually achieves a 
"reach" of 377, and is synched again, but some minutes lates, again loses 
synch.

I went into /etc/ntp.conf, commented out the 192.168.0.230 server line, and 
uncommented the commented out default server lines. Stopped, and started the 
ntp daemon, and got the same results. After some time synchronization is 
lost.

By contrast, booting FC5 on the same machine, which has 192.168.0.230 as the 
server line in /etc/ntp.conf, I have no problems. When it's synched it's 
polling every 64 secs, and progressively polls at longer intervals, as below. 
This is over about some 2hrs.

ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 192.168.0.230   80.127.4.179     2 u   56   64    3    0.543  7201255   1.797
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 192.168.0.230   80.127.4.179     2 u   55   64   17    0.371   -3.387   1.807
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u   51   64  177    0.351   -5.402   2.832
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  103  128  377    0.316  -18.440   4.938
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  119  128  377    0.316  -18.440   4.479
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u   58  128  377    0.364  -23.597   0.662

ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u   27  128  377    0.376  -24.385   1.127
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  108  128  377    0.351  -22.874   1.609
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u    7  128  377    0.351  -22.874   2.574
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u   52  128  377    0.382  -20.714   2.112
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  170  256  377    0.382  -20.714   2.280
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  112  256  377    0.391  -17.659   3.253
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  139  256  377    0.359  -10.552   1.658
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  200  256  377    0.392   -7.807   1.354
ntpq> pe
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*192.168.0.230   80.127.4.179     2 u  198 1024  377    0.480    5.336   1.668
ntpq>

The kernel I booted FC5 with is 2.6.17-1.2174_FC5, and the kernel I was using 
on Fedora 7, was 2.6.22.6. A realtime kernel from planetccrma.

I know I'm not being of any help. Just some observations from my machines, but 
there does appear to be some problem with NTP on Fedora 7 from my own 
observations.

Sorry I can't offer  a fix.

Nigel.




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