On Fri, 5 Jun 2009, Doug Barton wrote:
Frank Behrens wrote:
Edwin Groothuis <ed...@freebsd.org> wrote on 5 Jun 2009 22:44:
After pondering at conf/58595, I came with this text.
The ntpd is not enabled by default, so the fact that the servers
are commented out should not be an issue.
...
+# server pool.ntp.org
+# server pool.ntp.org
+# server pool.ntp.org
Isn't it better to use different entries?
server 0.pool.ntp.org
server 1.pool.ntp.org
server 2.pool.ntp.org
To be sure that the IP addresses are different.
See
http://www.pool.ntp.org/en/use.html
I agree with this suggestion, as well as the others about adding the
default restrictions and the fallback local clock.
I use 1 hard-coded server (= a local server for all machines except
1) (plus fallback to the local clock for all machines) and have never
had any problems using only 1 (except if the server is not up at boot
time then ntpdate (which is configured separately anyway) fails and
ntpd -x takes too long to sync so I sync manually. too long:= more
than 30 seconds, and I use -x since any slew except ones done at boot
time by ntpdate is considered an error, and I use ntpdate instead of
ntpd -g[q] since ntpdate works perfectly while at least old versions
of ntpd -q are very broken).
Bruce is right
about the ntp.drift file name, however we already have existing stuff
that mentions ntpd.drift, and since it's specified on the command line
in rc.conf the problems of what it says in the code are bypassed.
This is a bug in rc.conf.
The drift file name is also extensively documented to be ntp.drift (in
/etc even) in ntpd's man page: from "man ntpd | col -bx":
% -f driftfile
% Specify the name and path of the frequency file, default
^^^^^^^
% /etc/ntp.drift. This is the same operation as the driftfile
^^^^ ^^^^^^^^^
% driftfile configuration command.
No, the default is not in /etc and is not named ntp.drift (even if the
above is ntpd's default when a driftfile is configured without specifying
a pathname to it (is this possible?) this is confusing.
% outside the acceptable range, ntpd enters the same state as when the
% ntp.drift file is not present. The intent of this behavior is to quickly
^^^^^^^^^
No need for a pathname here.
% Frequency Discipline
% The ntpd behavior at startup depends on whether the frequency file, usu-
% ally ntp.drift, exists. This file contains the latest estimate of clock
^^^^ ^^^^^^^^^
"usually" instead of "default" is fine.
% FILES
% /etc/ntp.conf the default name of the configuration file
% /etc/ntp.drift the default name of the drift file
^^^ ^^^^^^^^^ ^^^ ^^^^^^^
As above.
/var/db/ntpd.drift is not documented anywhere in $(find /usr/share/man)
of course.
...
One more thing, it was said some time ago that due to a quirk in how
ntpd works on our system that adding the following to the server line
makes it work more efficiently:
server foo iburst maxpoll 9
If someone smarter than me could confirm that it would be great. :)
I use iburst maxpoll 6 and used to use a different maxpoll and complicated
settings when I had a dialup internet connection (was 120 ms ping
latency; now 8; 0.150 ms to the local server). These settings probably
don't matter with fast connections.
Bruce
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