[ntp:questions] Re: minpoll and maxpoll
brad at stop.mail-abuse.org
Tue Dec 21 16:15:40 UTC 2004
At 3:15 PM +0000 2004-12-21, srui at fe.up.pt wrote:
> good enough to keep time between power cycles. In a normal situation with
> a big clock skew the NTP daemon crashes, so I was told that using a low
> value for minpoll would solve this and it would be the correct equivalent
> to a forced initial correction.
The daemon doesn't actually crash. What happens is that it sees
the difference as being too large, and it decides that it can't fix
this problem and quits.
> Is this true? What solutions do I have
> for this?
Whoever told you that was very, very wrong. Minpoll and maxpoll
have to do with how long ntpd will wait between sending volleys to
the selected time servers, to try and get an idea of what they think
the current time is and how that compares to the others, etc....
If you want to solve this problem, start up ntpd with a "-g"
option, so that ntpd is allowed to step the clock by large amounts
(only on startup). You can help your time server settle down to a
"good" value of time by putting "iburst" at the end of your
configuration lines, and you want to make sure to specify a "drift"
file to record the values that ntpd calculates for how much your
system clock is off from "real"time, which will allow it to settle
back down much faster on restart.
We've tried to address all these issues in the Community
Supported documentation at
<http://ntp.isc.org/bin/view/Support/WebHome>. You will want to pay
special attention to sections #4 and 5.
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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