> Le 1 août 2019 à 01:23, Chris <xxx.syseng....@gfsys.co.uk> a écrit : > > On 07/31/19 20:10, Andrew Harrison wrote: >> The backstory... I've been tasked with deploying a pair of Symmetricom >> TP1100 Time Providers with GPS antennae as the official time source for the >> company (replacing an ancient server with a Meinberg card in it). My >> company actually purchased the Symmetricoms a few years ago, but they never >> got around to putting them in production. No one was able or willing to put >> in the time to get them going. I started working at the company recently >> and they gave the project to me. >> >> I've got them up and running and my test ntp client (my Linux workstation >> running ntp 4.2.8p12) can pull time from them just fine. >> >> Now for the hard part. What we want to happen is that if the GPS of the >> primary Symmetricom goes offline, we want the clients to start getting time >> from the backup unit. >> >> Ideally what would happen is the GPS goes offline, the Symmetricom would set >> itself to a higher stratum level and the clients abandon it for the device >> that has the better stratum, but this is not what happens. >> >> I had to use Wireshark to see that instead, when the GPS goes offline, the >> Symmetricom stops advertising a stratum level (Wireshark shows "unspecified >> or invalid") while the leap indicator shows "clock unsynchronized" (3 I >> think it was). (When I enable the GPS again, Wireshark shows the stratum >> level coming through as 1 and leap indicator shows 0 "no warning".) >> >> On my workstation test client, ntp apparently doesn't know what to do when a >> time source stops indicating its stratum level so it keeps right on showing >> stratum 1 in ntpq output even though Wireshark clearly shows the packets >> coming through with stratum level "unspecified or invalid". >> >> So, my question is, can I configure ntp in such a way that it responds to >> either a lack of advertised stratum or a leap warning indicator greater than >> 0? >> >> >> Thanks! >> >>
If a server is reporting the stratum level « unspecified or invalid » the client will not use it in synchronizing. IIRC it will eventually show up as stratum 16. I think that the reason you are still seeing stratum 1 in your client ntpq output is that the client has not had enough time to figure out whether the server is really dead , or it was a glitch. This can take some time. Anyway, do not worry as the client network will not use it. There are no configuration options to change the client status instantaneously. > > > If you have 2 servers, both gps, then the polling host needs to > have config to allow fallback to the second unit when it fails. > Not a time server issue afaics, unless each has fallback ability in > itself. > > What you could do is run ntpd on a third host, polling both time > servers along with a host or two from an ntp pool, which should have > the ability to spot the outlier and continue providing accurate time. > Not sure about the overall behavior, but wouldn't take long to set > it up and check results... > > Chris > > _______________________________________________ > questions mailing list > questions@lists.ntp.org > http://lists.ntp.org/listinfo/questions « What’s the point? » J.C. _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
