[ntp:questions] Time slew doesn't seem to work
Richard B. Gilbert
rgilbert88 at comcast.net
Wed Apr 9 13:58:01 UTC 2008
> I've started ntpd with the -x option and defined at run-time (using ntpdc) 3
> servers. The client machine has an offset of +/- 2s with the ntp servers.
> In the NTP log file I find the following statements (extracted out of a
> total of 98):
> 9 Apr 07:46:13 ntpd: time slew 1.781571 s
> 9 Apr 08:01:16 ntpd: time slew 1.781200 s
> 9 Apr 08:17:21 ntpd: time slew 1.781085 s
> 9 Apr 08:32:33 ntpd: time slew 1.781807 s
> 9 Apr 08:48:37 ntpd: time slew 1.782273 s
> 9 Apr 09:04:38 ntpd: time slew 1.781004 s
> 9 Apr 09:19:42 ntpd: time slew 1.781344 s
> 9 Apr 09:34:46 ntpd: time slew 1.780407 s
> 9 Apr 09:49:50 ntpd: time slew 1.778824 s
> The times don't seem to converge.
> When I shut down the ntp daemon and try to slew the time using ntpdate with
> the -B option it does work. The time difference with the ntp servers
> gradually declines.
> We use Suse SLES10 (kernel version: 2.6.16).
> Does anybody have an idea on what's going wrong?
Something is VERY wrong there. It looks as if NTPD is making a massive
correction every fifteen minutes or so!
If you reboot without running NTPD, and set the time manually, how badly
does it drift? If it gains or loses more than something like 43 seconds
per day, NTPD will not work until you get your hardware fixed. Gaining
or losing 1 or 2 seconds per day without NTPD is the expected level of
performance for a typical computer clock. (You get the finest hardware
that $2 US can buy!)
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