Brian Utterback wrote:
So, I still think that at least three servers would be a good idea.
I am thinking that if you pick three servers, and configure each
of them with three independent Internet servers and have them peer
with each other, that you will have a pretty robust system with
a minimum of administrative overhead. This assumes that the choice
of pool servers will be independent between them.
That's interesting. Lurking on this group I had always the impression that using
stratum 1 servers for small companies is frowned upon. But now both your answer
and the answer by Richard point into a different directions, namely to use them
as well: If I have three different independent Internet servers for three
internal servers, I need nine Internet servers. (In the case of four x four
servers, I need 16 Internet servers.)
The pool delivers only three servers per region (with multiple IP numbers, but
that is for load balancing, as far as I understand). That means that one either
has to use another national pool which is often not as near net-wise. Or one
selects 6 or 13 other Internet servers. When I look at the public stratum 2
servers at http://ntp.isc.org/bin/view/Servers/StratumTwoTimeServers, I'm hard
pressed to find 6 or 13 servers in Germany or nearby Europe. That means I have
to resort to stratum 1 servers.
Is this really the recommendation that I should formulate for the NTP Support
Wiki? That's why I asked how many company servers should sync to Internet servers.
Also, it is a good idea to configure local refclocks as Martin
described. I know that the scenario was for only a few hours, but there
was that 9 day anomaly, wasn't there?
Yes, the rationale goes as this: 97.5% SLA over the year means a maximum outage
of 9.something days. But usually Internet outages are below one day, just a few
hours. Outages that are really longer most often happen during very hard weather
storms, or similar conditions. Therefore I regard them as major outages and
think they should not be handled by normal operational precautions, but by
disaster recovery. Typically, one has much more problems in case of a major
outage than an unsynchronized timeserver. (Email comes to mind, that is
mission-critical, even for small to medium companies.)
Best,
Joachim
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Joachim Schrod Email: [EMAIL PROTECTED]
Roedermark, Germany
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