Re: [chrony-users] Advice on a private stratum 2 pool

[Miroslav Lichvar <mlichvar@xxxxxxxxxx>]

On Sun, Jun 30, 2019 at 09:57:55PM +0200, Youssef Ghorbal wrote:
> => On the client side too, the one ntp the peer "elected" as the best
> is also the one chosed by the client. This Option seems to be more
> aligned with previsously referenced architecture but I can't tell why
> I don't like it (maybe that I'm expecting  that my pool would be
> stratum uniform)

chronyd as an NTP client prefers sources with the shortest root
dinstance (which includes root delay and dispersion), giving the
stratum only a small weight in the selection. If you increase the
stratumweight value in the config file, for example to one second, it
will strongly prefer lower-stratum sources.

> Do you think that I should be using the same 4 upstream NTP stratum 1
> servers on all my stratum 2 servers? My failure scenario is if one of
> those upstream is faulty, my pool detect it and everything continues
> to work (and if my Internet connection is dead, I have more bigger
> problems than NTP going out of sync)

If your clients will be using all your servers and are able to detect
falsetickers, then it probably will not make a big difference on their
clocks. Generally, I think it's preferred to use more sources on lower
strata to detect problems sooner in the chain.

> How would you do it ? Do you have any pointers to reference NTP architectures ?

I think all three setups you have described make sense and should work
ok. There may be differences in how the clients are affected depending
on what clocks and network links fail.

I'd probably configure all stratum 2 servers to use all four stratum 1
servers and not configure them to peer with each other.

-- 
Miroslav Lichvar

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