[ntp:questions] client configuration: it's sufficient 3 servers ?
David Lord
snews at lordynet.org
Fri May 24 14:07:59 UTC 2013
David Lord wrote:
> Riccardo Castellani wrote:
>> If I have 3 internal NTP servers, what do you think if my clients have
>> all these 3 servers in their configuration ?
>> According to '5.3.2. Why should I have more than one clock?' in
>> 'http://www.ntp.org/ntpfaq/NTP-s-algo-real.htm#Q-NTP-ALGO
>>
>>
>> I read 2 servers, it's worst case, but also 3...
>
> My four pool servers each have 5 x internet sources
> (= 20 different internet sources) and 2 x local peers,
> there are also local sources with MSF and GPS.
>
> There is an explanation of the selection algorithm in
> the ntpd documentation as to why having only 2 and 3
> sources can give problems. That sets 4 as minimum and
> 5 for safety.
>
> I've had internet outages where half the sources have
> become unreachable.
>
> David
see <http://www.eecis.udel.edu/~mills/ntp/html/select.html>
David
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