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

[Youssef Ghorbal <youssef.ghorbal@xxxxxxxxx>]

Thank you Miroslav


On Mon, Jul 1, 2019 at 1:40 PM Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:
>
> 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.

That did the trick indeed !
By the way, on CentOS 7 stratumweight defaults to 0 (enforced in the
chrony.conf provided by the package)

>
> > 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.

Understood.

> > 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.

I think I'll go with this configuration.

> --
> Miroslav Lichvar
>
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