On 2011-12-09, Miguel Gon?alves <[email protected]> wrote: > Hi! > > This morning my FreeBSD 7.4 Oncore UT+ NTP server exhibited a strange > behaviour... Note the huge jump in offset from 854 ns to 596 us and then > the highest offset at 159 ms. > > loop stats file: > > 55904 33635.224 0.000001230 -1.282 0.000000888 0.001755 4 > 55904 33651.224 0.000000854 -1.282 0.000000807 0.001642 4 > 55904 33667.224 -0.000596143 98.718 0.000167778 35.355334 4 > 55904 33683.227 -0.002127304 98.718 0.000187390 33.071886 4 > 55904 33699.227 -0.003561445 98.718 0.000176065 30.935917 4 > 55904 33715.228 -0.004910077 98.718 0.000165214 28.937901 4 > 55904 33731.231 -0.006175330 98.718 0.000155121 27.068927 4 > 55904 33747.230 -0.007362986 98.718 0.000145378 25.320663 4 > 55904 33763.231 -0.008479146 98.718 0.000136915 23.685311 4 > 55904 33779.232 -0.009525378 98.718 0.000128152 22.155580 4 > 55904 33795.233 -0.010508291 98.718 0.000120356 20.724648 4 > 55904 33811.233 -0.011431854 98.718 0.000113179 19.386133 4 > 55904 33827.236 -0.012298303 98.718 0.000106061 18.134067 4 > 55904 33843.235 -0.013111000 98.718 0.000099472 16.962866 4 > 55904 33859.235 -0.013875647 98.718 0.000093789 15.867308 4 > 55904 33875.246 -0.014592572 98.718 0.000087576 14.842508 4 > 55904 33891.236 -0.015265789 98.718 0.000082514 13.883895 4 > 55904 33907.237 -0.015897754 98.718 0.000077516 12.987194 4 > 55904 33923.237 -0.015990842 -1.281 0.000113346 37.383905 4 > 55904 33939.235 -0.015012221 -1.281 0.000119575 34.969441 4 > > clock stats file: > > 55904 33650.223 127.127.30.0 3532411249.999999141 2011 343 9 20 50 49 > rstat 08 dop 0.0 nsat 9,7 traim 1,0,0 sigma 41 neg-sawtooth -34 sat > 38888888 > 55904 33651.223 127.127.30.0 3532411250.999999704 2011 343 9 20 51 50 > rstat 08 dop 0.0 nsat 9,7 traim 1,0,0 sigma 41 neg-sawtooth -49 sat > 38888888 > > The machine is running 4.2.6p4. What might have caused this? This machine > does nothing else providing NTP to the network. > The most likely cause for the offset change that you observed was related to the satellite position relationship taking a bad track. This is minimized by setting a higher mask angle in your Oncore configuration and not use satellites below 10 degrees above the horizon. If you have trees or other obstuctions in the area, use an even higher angle. GPS satellites have their maximum accuracy when their path to you is 'high in the sky' and without obstructions.
It is unfortunate that you chopped off the portion of your clockstats file that coincided with 'something interesting' being recorded in your loopstats file. This occurred at 55904 33667.224 in the log. Tom -- Public Keys: PGP KeyID = 0x5F22FDC1 GnuPG KeyID = 0x620836CF _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
