On May 26, 4:14 pm, "Richard B. Gilbert" <[email protected]> wrote: > Terje Mathisen wrote: > > Andy wrote: > >> About 10 years ago we used to have 2 seperate GPS receivers feeding > >> into two Sparc servers via their serial port. I can't remember the > >> version of NTP we ran however these were our stratum one servers, One > >> of the Sparcs developed a fault on it's serial interface which delayed > >> the input meaning the two stratum one servers started showing > >> different time so all the statum 2 servers stopped trusting both > >> stratum 1 servers as they could not determine which server, if any, > >> was telling the truth. Ever since then we have always used at least 3 > >> stratum one servers with seperate stratum zero sources to form a > >> quorum so that startum 2 can differentiate the good from the bad. I > >> believe this is set down as best practise in the ntp.org FAQ - this is > >> a practical example of why this is wise. > > > The "best practice" is in fact to use at least _four_ sources, that way > > you can lose one and still have a voting group. > > > Terje > > The magic numbers are 4, 5 and 7 protecting from the failure of one, > two, or three servers respectively. If you can't do it with seven > servers you have more serious problems!- Hide quoted text - > > - Show quoted text -
We use 4 at the moment, we had 5 but we've decommissioned a building that housed one recently. Interestingly I'm having difficulty convincing some new colleagues that we need more than two!......... _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
