On 27 January 2016 at 08:53, Dirk Deimeke <dirk at deimeke.net> wrote: > On 2016-01-27 09:36, John R Pierce wrote: > > Hi! > >> ntpd won't make drastic changes in the time, if its too far off. its >> designed to stabilize the clock by making small changes in speeding it >> up or slowing it down, and not 'staircase' setting it absolutely. > > > http://www.ntp.org/ntpfaq/NTP-s-algo.htm#Q-ALGO-BASIC-STEP-SLEW > > Apart from that, the ntp-implementation (or chrony nowadays) "wants" to have > more than one time source. > > http://www.ntp.org/ntpfaq/NTP-s-algo-real.htm#Q-NTP-ALGO > > It's best practice to have a reasonable pool of sources (3, 5 or 7 depending on how many false tickers you want to be able to cope with) but it can run against a single source, with the understanding that it has to trust it as real time since there's nothing to compare it to.