Date: Thu, 15 May 2008 12:18:57 -0700 From: Chuck Swiger <cswiger@mac.com> To: Volker Jahns <volker@thalreit.de> Cc: freebsd-questions@freebsd.org Subject: Re: time drift Message-ID: <597571FB-C72D-4603-B379-A59A435843BE@mac.com> In-Reply-To: <20080515185758.GA12709@ikarus.thalreit> References: <20080515185758.GA12709@ikarus.thalreit>
next in thread | previous in thread | raw e-mail | index | archive | help
On May 15, 2008, at 11:57 AM, Volker Jahns wrote: > FreeBSD 6.2 running on X86 hardware (FSC) shows a remarkable time > drift > > running ntpdate every half hour shows that the system looses about > 10-14 sec each time. > 15 May 10:06:48 ntpdate[7200]: step time server 192.53.103.108 > offset -13.799602 sec > 15 May 10:36:48 ntpdate[7515]: step time server 192.53.103.108 > offset -12.813941 sec > 15 May 11:06:48 ntpdate[7879]: step time server 192.53.103.108 > offset -13.651921 sec > 15 May 11:36:50 ntpdate[8079]: step time server 192.53.103.108 > offset -11.109298 sec > 15 May 12:06:50 ntpdate[8289]: step time server 192.53.103.108 > offset -11.836499 sec While you should run ntpdate -b at system boot, running ntpdate periodically via cron is not the right thing to do-- you should run ntpd instead, and that will figure out the intrinsic correction your chosen system clock needs to keep better time via the ntp.drift file. You should also take a look at the output of "sysctl kern.timecounter", and possibly switch to a different mechanism, if the existing choice doesn't work out well for your machine... Regards, -- -Chuck
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?597571FB-C72D-4603-B379-A59A435843BE>