[ntp:questions] Beginner needs help...

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Tue Mar 8 06:32:04 UTC 2011

Chris Albertson wrote:
> On Mon, Mar 7, 2011 at 2:11 PM, David Woolley
> <david at ex.djwhome.demon.invalid>  wrote:
>> Terje Mathisen wrote:
>>> David Woolley wrote:
>>>> Chris Albertson wrote:
>>>>> If you are on an isolated network a better setup is to put three
>>>>> SERVER lines in each config file where each of the tree computers has
>>>>> itself and the other two to select from. ntp will find the best clock
>>>> That's a recipe for disaster. If you are a rime island and you do
>>>> something like this, orphan mode is essential. Without orphan mode, the
>>>> OP is correct in using a well defined tree structure.
>>> Yes and no:
>>> The ability of ntpd to disregard circular definitions, i.e. using itself
>>> as server, made it possible for me to use the exact same ntp.conf file for
>>> all of my 6 primary servers:
>> The concern I have is that such configurations, without a real source of
>> time are liable to fragment.
> Yes.  I think you are right.  I've done the three server lines, thing
> as I suggested above and it worked but I can see where it might
> fragment.  I guess that would depend on luck.  The orphan mode solves
> this problem.
> The problem is that on an isolated island of N servers you want to
> automatically select the one server that has the "best" clock even
> when some computers are not running.  I think "orphan" handles this.

A RAIG (Redundant Array of Inexpensive GPSs) setup solves that problem 
as well. :-)

I.e. as I wrote I have 3 Oncores as well.


- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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