Time problem with ntpd
David G. Miller
dave at davenjudy.org
Sat Oct 7 14:29:05 UTC 2006
"jdow" <jdow at earthlink.net> wrote:
>From: "Rob Brown-Bayliss" <uncertain.genius at gmail.com>
>> On 10/7/06, Rob Brown-Bayliss <uncertain.genius at gmail.com> wrote:
>>>>> Hi, I noticed this aftetrnoon that my system clock is about 23 minutes
>>>>> fast. I ma using ntpd, and earlier today it was reporting the correct
>>> In the last few mins the time has corrected it's self. But can UI
>>> trust the system clock any more?
>You can answer that for yourself by using ntpq.
>>From the ntpq prompt "peers" is interesting. It allows other perhaps
>less interesting commands like "assoc" and exploration of the parameters.
>The command "ntpq -p" simply returns the peers list.
>Monitor this for extended periods and see why your system wanders off.
>It requires a day or two of continuous online time for ntpd to fully
>characterize your system and get the clock in line so that long periods
>off line (a day or so) involve no traumatic corrections or errors.
You can also try the ntptrace command. You should see something like:
localhost.localdomain: stratum 4, offset 0.000022, synch distance 0.234200
mutilate.local.davenjudy.org: stratum 3, offset -0.010917, synch
vine.desynched.net: stratum 2, offset 0.000191, synch distance 0.096220
time-C.timefreq.bldrdoc.gov: stratum 1, offset 0.000000, synch distance
0.002650, refid 'ACTS'
If all you see is something about "127.127.1.0 stratum 10", your ntpd is
unable to find a time source so you're running from the system clock.
Also, ntp only syncs the system clock at shutdown. If you leave your
system up but drop your network connection, ntp will do its best using
the system clock but don't expect much. Finally, ntp will only slowly
correct the reported time to prevent discontinuities. It should not
have changed the time by 23 minutes over only a few hours. You may have
something else going on.
Here's a link that may help: http://www.ntp.org/ntpfaq/NTP-s-trouble.htm
Politics, n. Strife of interests masquerading as a contest of principles.
-- Ambrose Bierce
More information about the users