[ntp:questions] Re: NTP Pool rules vs. four-server advice

Michael Deutschmann michael at talamasca.ocis.net
Tue Dec 20 04:21:53 UTC 2005

On Mon, 19 Dec 2005, Richard B. Gilbert wrote:
> Michael Deutschmann wrote:
> >I've noticed a conflict between the instructions on the NTP server Pool
> >project page and other NTP advice.
> >
> > [... NTP guideline is to use 1, 4 or more servers.  Pool ettiquette
> >  says only 3 servers total ...]
> [... Stuff about how hard it is for the pool ...]

That's not really relevant to the argument.

If by bringing this up you are trying to say that the pool would collapse
with a "ration" of 4 servers per user, then the "ration" should be set at
1, since those two extra servers for people ignoring the 1-or-4 rule
aren't doing them any good.  (Assuming that the 1-or-4 rule itself is
actually technically justified, of course).

> So configure three pool servers and one public access stratum 2 server
> and you comply with both sets of rules.

As I understand it, this would break the pool rules.  From
http://www.pool.ntp.org/use.html, under "Additional Notes":
# * If your Internet provider has a timeserver, or if you know of a
#   good timeserver near you, you should use that and not this list -
#   you'll probably get better time and you'll use fewer network
#   resources. If you know only one timeserver near you, you can of
#   course use that and two from pool.ntp.org or so.

This says "two from pool.ntp.org" when you would otherwise have a
"fourth" non-pool reference, not three.

And also:
# * Be friendly. Many servers are provided by volunteers, and almost
#   all time servers are really file or mail or webservers which just
#   happen to also run ntp. So don't use more than three time servers
#   in your configuration, and don't play dirty tricks with burst or
#   minpoll - all you will gain is that this project will be stopped
#   sooner or later.

It says "don't use more than three time servers", not "don't use more
than three _pool_ time servers".

---- Michael Deutschmann <michael at talamasca.ocis.net>

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