Maarten,
Setups involving more than two cohabitating local clocks are
fundamentally unstable under some failure scenarios. The recently
implemented orphan mode is designed for graceful fallback under failure
conditions. It is in the latest ntp-dev that leaves here, but is still
pretty new.
You are welcome to try it by using the tos orphan <stratum> in all
machines in addition to your normal outside servers. For the most
survivable configuration configure a fully connected mesh network among
the servers and clients, either using broadcast or symmetric modes. If
anything fails, the subnet will automatically reconfigure elect a subnet
root and form a connected tree. If any server or client finds an outside
source, the tree reconfigures as usual.
Dave
Maarten Wiltink wrote:
"Donat-Pierre Luigi" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
[...]
The stratum on A and C is set to 14 and it is set to 13 on B. That
is to say, I used each local clock as fall back reference clock and
used fudge to set the stratum with bias towards B.
After several attempts at debugging and reading NTP documentations
and feeling really confused, I can't prevent A and C to drift away
without converging or stabilizing (i.e. with a stable offset) with
the clock of the Windows XP PC B.
The bias may be too small. A and C now have a choice between B's
stratum 14 (it's one step away from its own clock) and their local
clocks' stratum 14. The local clock is likely to win. Try fudging
B's clock to stratum 12.
[...]
I would still like PC B to use up to four external servers (as
recommended) whenever it has a network connection. What is important
to me is that the Cluster PCs have a small time difference between
themselves - i.e. synch together. That is to say, the accuracy of the
absolute time is not as essential, it just need to be reasonable within
seconds.
If they have connectivity _sometimes_, simply configure a few NTP pool
servers. If they're not reachable, so what? No harm is done.
Also, what I would really like is that the two Linux PC (A and C)
display the minimum time offset with respect to each other.
Shall I configure A and C to peer with each other so that each clocks
minimize the relative error with the reference clock from B?
No, that won't help if B is reachable.
Groetjes,
Maarten Wiltink
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