[ntp:questions] Re: NTP does not sync when using pool.ntp.org

Adrian 'Dagurashibanipal' von Bidder grazdan at fortytwo.ch
Thu Oct 9 16:16:00 UTC 2003


Clinging to sanity, Dale Worley mumbled in his beard:

> mayer at gis.net (Danny Mayer) writes:
>> In summary, you can't depend on NTP getting different IP addresses each
>> time it looks up a name. It depends on the O/S, the resolver, and the
>> nameservers being used by the system, each of which may be different.
> 
> I don't remember whether someone has suggested this before, but one
> solution would be to define "pool1.ntp.org", "pool2.ntp.org", and
> "pool3.ntp.org" to be round-robins with exactly the same sets of
> names.  That way,
> 
>         server pool1.ntp.org
>         server pool2.ntp.org
>         server pool3.ntp.org
> 
> would defeat most resolver deficiencies.

Yes, it was suggested (and it did even exist in the very beginning - and I
may think about it again in the future).

The main reason why this doesn't exist right now is:
To achieve the desired effect, {1,2,3}.pool.ntp.org would need to be
disjunct. But since we want load balancing, and not just load every server
in the pool, we would need to have a few names in each zone still - so we'd
need >30 servers - for each zone (continental, country zones, too!).

With currently 90 servers in toto, I don't think this works.

The question is, of course: how important is consistency? If you say 'not
important', then I could introduce 
{1,2,3}[.{north-america,europe,us,ch,nl}].pool.ntp.org now, and the rest
later (I have recently switched to a database storage, so it would be less
work than with the previous file-based scheme). The main problem after this
would then be to have this documented.

cheers
-- vbi

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