[ntp:questions] Re: ntp.drift
Richard B. Gilbert
rgilbert88 at comcast.net
Fri Jan 28 04:06:28 UTC 2005
Walter HILL wrote:
> Martin Burnicki wrote:
>> Walter HILL wrote:
>>> I have a Sun Blade 100 workstation running Linux 2.4.27 and have
>>> compiled and installed ntpd
>>> The computer has been running for several weeks yet the ntp.drift file
>>> still contains 0.000. Yes ntp.conf contains
>>> driftfile /var/lib/ntp/ntp.drift
>>> The computer was losing about 2s / hour prior.
>>> Is there another parameter required in ntp.conf?
>> There are 2 things you could check:
>> 1.) Has the NTP daemon synchronized to some time source other than
>> clock", i.e. is there a '*' in the first column of the output ot the
>> command "ntpq -p"? If in doubt, please post that output here.
> remote refid st t when poll reach delay offset
> +nimda.mailworx. 188.8.131.52 2 u 223 1024 77 296.561 1336.97
> caenis 184.108.40.206 2 u 22 64 377 1.724 827.625
> *cerberus 220.127.116.11 2 u 26 64 377 0.729 896.530
> LOCAL(0) LOCAL(0) 10 l 20 64 377 0.000 0.000
> caenis and cerberus are on the local subnet.
Something is very wrong here!! Your offset and jitter numbers two
orders of magnitude too large. I expect offsets and jitter to be less
than twenty milliseconds; usually a lot less! A round trip delay of
296.561 milliseconds seems excessive unless you are using tin cans and
I'd suggested configuring several more servers and selecting a set of at
least four servers with low round trip delays and low jitter.
I'm not sure what the problem with your drift file might be but you
should not have to create a drift file or seed it with a value! I would
suggest deleting the existing file. ntpd should create a new file with
a drift value in it. The ntpd daemon should create a temporary file
with a new value, delete the existing file and rename the temporary file
each hour. Make sure that ntpd has write access to /var/lib/ntp.
On some flavors of Unix ntpd runs, not as root, but as user "ntp". It
is so with Red Hat. If Gentoo is the same, make sure that /var/lib/ntp
is owned by ntp with permissions rwxr-xr-x. If the existing file is not
owned by ntp, either delete it or chown ntp /var/lib/ntp/drift; chgrp
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