On 12/16/2011 7:59 PM, [email protected] wrote:
The scenario I'm worried about somewhat different from what has been
described in this thread. I though I would add it to the chain as a use
case developers should be aware of.
I frequently see incorrect time after a system has been powered off or
even just booted. The amount of time varies and typically less than a
second, but sometimes much more.
Following is an example of why I want to just quickly set the time on a
boot. Booting up around 15:30, ntpd starts. Twenty minutes later, ntpd
is ready to use its -g option and resets time. This fixes the error that
occurred while the system was down. Before and after the boot, ntpd
manages time with small drift values and no time resets.
But I can not afford to have time reset by -4 seconds after my
applications have been running for 20 minutes. I also can not wait for 20
minutes to start running applications.
I don't care if the command to set system time from the timeservers is
ntpdate or ntpd -gq. My two requirements are 1) to set a time that will
be close enough for ntpd to manage without resets and 2) to set that time
within a few seconds of being run.
Nov 20 15:30:06 ntpd[4969]: ntpd [email protected] Tue Feb 10 22:33:50 UTC
2009 (1)
Nov 20 15:30:06 ntpd[4971]: precision = 1.000 usec
. . .
Nov 20 15:30:06 ntpd[4971]: kernel time sync status 0040
Nov 20 15:30:06 ntpd[4971]: frequency initialized 18.666 PPM from
/var/lib/ntp/drift
Nov 20 15:34:00 ntpd[4971]: synchronized to LOCAL(0), stratum 10
Nov 20 15:34:00 ntpd[4971]: kernel time sync enabled 0001
Nov 20 15:35:05 ntpd[4971]: synchronized to 192.90.175.9, stratum 2
Nov 20 15:49:57 ntpd[4971]: time reset -4.358850 s
Nov 20 15:53:23 ntpd[4971]: synchronized to LOCAL(0), stratum 10
Nov 20 15:55:34 ntpd[4971]: synchronized to 192.90.175.9, stratum 2
If Notes or I don't get this message correctly into the thread, I
apologize.
Try running your system 24x7! If you can't do that, try a program
called "chrony". NTPD was never intended for "off again, on again" service!
If you can run NTPD 24x7, do so and enjoy.
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