[time-nuts] Noob question, NTP stratum 1.

[Luiz Paulo Damaceno]

Dear colleagues, i've made some tests and wrote an article about Raspberry
Pi as a timeserver. I think we can trust on it and this board can keep a
good time from GNSS PPS. I'm open to suggestions. I hope this can help in
the decision making process. The link: rpi_article
<https://www.researchgate.net/publication/334179026_Credit_card_size_computer_Stratum_1_NTP_Server>

Also, in our tests as you can see in the article, for general purposes the
RPI has a good dealing with high loads. The difference is we've removed the
crystal oscillator and put a signal from a synthesizer, you can keep the
crystal and trust on pps signal too. I'm using a server at home with a
cheap module NEO-6M and also one with SAM-M8Q. For comparsions effect i've
put the NEO-6M to compare the ntp time of the rpi that this receiver is
connected to with the server from the article: you can see in the
thingspeak: thingspeak_channel
<https://thingspeak.com/channels/691405/>

If you want the source code for the 1 PPS generation thats it:
1pps_generation_src_code
<https://github.com/LuizPauloDamaceno/rpi_pps_out/blob/master/ppsout.c>

Best regards,

Luiz

Em seg, 22 de jul de 2019 às 11:05, wildylion via time-nuts <
time-nuts at lists.febo.com> escreveu:

> Hello there,
>
> I wanted to ask for advice regarding NTP
>
> Situation 1:
> What I currently have is a uBlox M8N GPS puck I'm planning to use with the
> Raspberry PI. Seems like it should work almost out of the box with some
> kernel tuning, but I have a question about short term stability in the
> event of GPS loss - how well will the board hold over if it's lost GPS for,
> say, 24 hours?
>
> Situation 2:
> Also, there's a need for more dependable NTP time sources for our
> colocated spaces.
>
> What we have is about 100 servers, some of them running DBMS that wouldn't
> like clock drift at all. After a recent incident involving NTP I've got an
> idea to install GPSDO time servers in each datacenter and slave them to
> stratum2's that will be actually distributing time to clients.
>
> All the certified GNSS disciplined clocks are really expensive (way more
> than the management would approve), so what I'm planning to do is possibly
> getting a couple LeoNTP units and using them as the root time sources,
> would this be a good plan? Of course, all the NTP infrastructure will be
> monitored, and possibly we'll use Stratum 2 servers which would be slaved
> to GPSDO S1's AND the public NTP pool for sanity checks.
>
> Maybe BG7TBL's units instead of LeoNTP?
> Is that a good idea?
>
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