[ntp:questions] Re: ntpd, boot time, and hot plugging
brad at stop.mail-abuse.org
Thu Feb 3 23:55:01 UTC 2005
At 9:03 PM -0200 2005-02-03, Alain wrote:
> So, if I manage to set the initial time within a good aproximation od
> "real" time using ntpdate using 5 servers as explained earlyer, would
> you recomend to delete the drift file and let it start all over again?
If the drift file states +/- 500ms, then I would be inclined to
remove it on startup no matter what. Of course, I would also be
inclined to use "ntpd -g" instead of ntpdate, for the reasons I've
previously given you, not to mention the issues that you have
mentioned here regarding the use of ntpdate against servers that are
> Does this afect the time for the server to start serving?
If the drift file is whacked out, it's better to remove it and
let the server re-calculate, than to try to compensate for a whacked
out drift file. You'll start serving time faster if you let the
system try to calculate the real situation once the clock has been
set to a reasonable value on startup.
Keep in mind that the server will have to take extra time to get
to a state where it can start serving time to clients, if it has had
to calculate a new drift file or try to deal with a whacked out drift
file. If you're sensitive to seven seconds of additional startup
time, then you really, really want to make sure that you always keep
a reasonable drift file.
Given the kinds of time periods we're talking about, I still have
yet to see a good reason for using "ntpdate; ntpd" instead of "ntpd
Brad Knowles, <brad at stop.mail-abuse.org>
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-- Benjamin Franklin (1706-1790), reply of the Pennsylvania
Assembly to the Governor, November 11, 1755
SAGE member since 1995. See <http://www.sage.org/> for more info.
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