[CentOS] Strange NTP problem
Filipe Brandenburger
filbranden at gmail.com
Wed May 21 01:09:23 UTC 2008
On Tue, May 20, 2008 at 8:53 PM, Alfred von Campe <alfred at von-campe.com> wrote:
> # ntpq -np
> remote refid st t when poll reach delay offset
> jitter
> ==============================================================================
> 10.101.32.104 67.128.71.65 3 u 689 1024 377 0.659 54095.7
> 4263.68
> *127.127.1.0 .LOCL. 10 l 28 64 377 0.000 0.000
> 0.001
>
> The bad system is synch'ing with itself (which was apparent from the
> messages in /var/log/messages). The question is why?
When the offset is too big, NTP will discard the server as a source of
synchronization. Try stoping ntpd, setting the date with ntpdate, then
starting ntpq -np again to see what happens.
I saw that the jitter appears to be really big too. That might be
caused by your server going too slow or too fast in a rate that NTP
couldn't keep up to. Once it happened to me, somehow (IRQ problems?)
one machine started going so fast that NTP couldn't keep up with it,
so I had to put periodic ntpdate's to keep it at the right time. I
rebooted it off-hours and the problem went away. Did you try rebooting
this machine and seeing if it fixes the problem?
One good side is the "reach = 377", that means your network is good
and all NTP packets are being exchanged correctly. 377 is octal for
binary 11111111, which means the last 8 NTP packet exchanges were
successful.
Good luck!
Filipe
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