NTPsec

Backup/Meinberg

Report generated: Tue Feb 3 16:43:01 2026 UTC
Start Time: Tue Jan 27 16:43:01 2026 UTC
End Time: Tue Feb 3 16:43:01 2026 UTC
Report Period: 7.0 days

Daily stats   Weekly stats  

Local Clock Time/Frequency Offsets

local offset plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Time Offset -97.646 -47.864 -28.103 -2.197 46.523 78.975 151.506 74.626 126.839 23.901 0.068 µs 1.5 9.331
Local Clock Frequency Offset 4.518 4.551 4.632 4.951 5.097 5.288 5.373 0.465 0.737 0.151 4.915 ppm -0.3905 3.044

The time and frequency offsets between the ntpd calculated time and the local system clock. Showing frequency offset (red, in parts per million, scale on right) and the time offset (blue, in μs, scale on left). Quick changes in time offset will lead to larger frequency offsets.

These are fields 3 (time) and 4 (frequency) from the loopstats log file.



Local RMS Time Jitter

local jitter plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Time Jitter 0.460 0.642 0.770 1.472 3.058 6.538 13.645 2.288 5.896 1.065 1.696 µs 4.381 33.7

The RMS Jitter of the local clock offset. In other words, how fast the local clock offset is changing.

Lower is better. An ideal system would be a horizontal line at 0μs.

RMS jitter is field 5 in the loopstats log file.



Local RMS Frequency Jitter

local stability plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Frequency Jitter 0.075 0.140 0.220 0.807 3.219 4.889 8.404 2.999 4.749 1.000 1.062 ppb 2.918 14.92

The RMS Frequency Jitter (aka wander) of the local clock's frequency. In other words, how fast the local clock changes frequency.

Lower is better. An ideal clock would be a horizontal line at 0ppm.

RMS Frequency Jitter is field 6 in the loopstats log file.



Local Clock Time Offset Histogram

local offset histogram plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Offset -97.646 -47.864 -28.103 -2.197 46.523 78.975 151.506 74.626 126.839 23.901 0.068 µs 1.5 9.331

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats log file.



Local Temperatures

local temps plot

Local temperatures. These will be site-specific depending upon what temperature sensors you collect data from. Temperature changes affect the local clock crystal frequency and stability. The math of how temperature changes frequency is complex, and also depends on crystal aging. So there is no easy way to correct for it in software. This is the single most important component of frequency drift.

The Local Temperatures are from field 3 from the tempstats log file.



Local Frequency/Temp

local freq temps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 4.518 4.551 4.632 4.951 5.097 5.288 5.373 0.465 0.737 0.151 4.915 ppm -0.3905 3.044
Temp /dev/sda 40.000 40.000 40.000 41.000 42.000 43.000 49.000 2.000 3.000 0.805 41.427 °C
Temp /dev/sdb 51.000 51.000 51.000 53.000 59.000 60.000 60.000 8.000 9.000 2.120 53.207 °C
Temp /dev/sdc 51.000 51.000 51.000 53.000 53.000 54.000 56.000 2.000 3.000 0.587 52.917 °C
Temp /dev/sdd 58.000 58.000 58.000 60.000 68.000 69.000 69.000 10.000 11.000 2.620 60.298 °C
Temp /dev/sde 40.000 40.000 41.000 42.000 43.000 43.000 43.000 2.000 3.000 0.595 41.676 °C
Temp /dev/sdf 52.000 52.000 52.000 53.000 60.000 61.000 62.000 8.000 9.000 2.163 53.715 °C
Temp LM0 24.750 25.000 25.500 26.750 27.750 30.250 47.500 2.250 5.250 1.208 26.808 °C
Temp LM1 37.000 38.000 38.500 40.000 41.500 41.500 43.000 3.000 3.500 0.841 40.137 °C
Temp LM10 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM11 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM12 40.000 40.000 40.000 41.000 42.000 43.000 49.000 2.000 3.000 0.805 41.427 °C
Temp LM13 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp LM14 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Temp LM15 26.000 26.250 26.750 28.000 29.250 31.500 37.500 2.500 5.250 0.971 28.182 °C
Temp LM16 52.000 52.000 52.000 53.000 60.000 61.000 62.000 8.000 9.000 2.182 53.796 °C
Temp LM17 55.500 56.000 56.500 58.000 59.000 62.500 63.500 2.500 6.500 1.028 57.948 °C
Temp LM18 58.000 58.000 58.000 60.000 68.000 69.000 69.000 10.000 11.000 2.629 60.411 °C
Temp LM19 51.000 51.000 51.000 53.000 59.000 60.000 60.000 8.000 9.000 2.129 53.284 °C
Temp LM2 40.000 40.000 41.000 42.000 43.000 43.000 43.000 2.000 3.000 0.593 41.672 °C
Temp LM20 23.000 23.000 24.000 26.000 27.000 30.000 98.000 3.000 7.000 3.171 25.870 °C
Temp LM21 21.000 23.000 24.000 25.000 27.000 29.000 98.000 3.000 6.000 3.064 25.683 °C
Temp LM22 19.000 20.000 21.000 23.000 25.000 28.000 94.000 4.000 8.000 2.870 23.133 °C
Temp LM23 20.000 22.000 22.000 24.000 26.000 29.000 93.000 4.000 7.000 2.929 24.369 °C
Temp LM24 22.000 22.000 23.000 25.000 26.000 29.000 89.000 3.000 7.000 2.700 24.929 °C
Temp LM3 29.000 29.000 30.000 31.000 32.000 32.000 37.000 2.000 3.000 0.831 30.920 °C
Temp LM4 27.000 27.500 28.000 30.000 31.500 32.000 33.500 3.500 4.500 1.052 30.071 °C
Temp LM5 24.000 24.000 24.000 24.000 24.000 24.000 24.000 0.000 0.000 0.000 24.000 °C
Temp LM6 29.000 29.000 29.000 29.000 29.000 29.000 29.000 0.000 0.000 0.000 29.000 °C
Temp LM7 56.000 56.000 56.000 58.000 59.000 62.000 63.000 3.000 6.000 1.070 57.682 °C
Temp LM8 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM9 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp ZONE0 22.000 23.000 24.000 25.000 27.000 30.000 100.000 3.000 7.000 3.222 25.651 °C
Temp ZONE1 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp ZONE2 55.500 56.000 56.500 58.000 59.000 62.500 64.000 2.500 6.500 1.031 57.945 °C
Temp ZONE3 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C

The frequency offsets and temperatures. Showing frequency offset (red, in parts per million, scale on right) and the temperatures.

These are field 4 (frequency) from the loopstats log file, and field 3 from the tempstats log file.



Server Offsets

peer offsets plot

The offset of all refclocks and servers. This can be useful to see if offset changes are happening in a single clock or all clocks together.

Clock Offset is field 5 in the peerstats log file.



Server Offset 2001:470:e815::8 (spidey.rellim.com)

peer offset 2001:470:e815::8 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2001:470:e815::8 (spidey.rellim.com) -4.928 -1.612 -0.900 0.440 1.970 2.850 4.025 2.870 4.462 0.909 0.478 ms -0.02252 4.136

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.17.205.1

peer offset 204.17.205.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.1 -4.426 -1.627 -0.190 1.090 2.121 2.925 3.039 2.311 4.552 0.781 1.032 ms -1.802 13.41

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.17.205.24

peer offset 204.17.205.24 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.24 -79.547 -29.486 -11.422 0.079 2.626 6.355 35.035 14.048 35.841 5.772 -1.209 ms -4.119 29.76

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.17.205.27

peer offset 204.17.205.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.27 -6.826 -5.445 -1.317 0.198 1.720 4.147 5.297 3.038 9.592 1.189 0.154 ms -0.969 13.24

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset SHM(0)

peer offset SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(0) -97.647 -47.865 -28.104 -2.198 46.524 78.976 151.507 74.628 126.841 23.902 0.068 µs 1.5 9.33

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Jitters

peer jitters plot

The RMS Jitter of all refclocks and servers. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 2001:470:e815::8 (spidey.rellim.com)

peer jitter 2001:470:e815::8 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 2.090 4.885 8.171 38.297 118.575 372.589 1,337.683 110.404 367.704 75.939 53.344 µs 8.071 98.42

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.17.205.1

peer jitter 204.17.205.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.1 2.708 6.445 8.979 19.529 54.624 146.971 460.103 45.645 140.526 28.840 25.948 µs 7.783 87.6

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.17.205.24

peer jitter 204.17.205.24 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.24 0.007 0.029 0.121 4.793 17.093 38.080 262.164 16.972 38.051 11.831 6.514 ms 10.71 167.2

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.17.205.27

peer jitter 204.17.205.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.27 2.621 5.614 9.575 74.196 167.591 269.083 1,069.746 158.016 263.469 62.487 78.616 µs 3.231 38.01

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter SHM(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(0) 0.174 0.541 0.978 4.154 12.678 23.758 77.020 11.700 23.217 5.226 5.393 µs 4.801 43.9

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 4.518 4.551 4.632 4.951 5.097 5.288 5.373 0.465 0.737 0.151 4.915 ppm -0.3905 3.044
Local Clock Time Offset -97.646 -47.864 -28.103 -2.197 46.523 78.975 151.506 74.626 126.839 23.901 0.068 µs 1.5 9.331
Local RMS Frequency Jitter 0.075 0.140 0.220 0.807 3.219 4.889 8.404 2.999 4.749 1.000 1.062 ppb 2.918 14.92
Local RMS Time Jitter 0.460 0.642 0.770 1.472 3.058 6.538 13.645 2.288 5.896 1.065 1.696 µs 4.381 33.7
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 2.090 4.885 8.171 38.297 118.575 372.589 1,337.683 110.404 367.704 75.939 53.344 µs 8.071 98.42
Server Jitter 204.17.205.1 2.708 6.445 8.979 19.529 54.624 146.971 460.103 45.645 140.526 28.840 25.948 µs 7.783 87.6
Server Jitter 204.17.205.24 0.007 0.029 0.121 4.793 17.093 38.080 262.164 16.972 38.051 11.831 6.514 ms 10.71 167.2
Server Jitter 204.17.205.27 2.621 5.614 9.575 74.196 167.591 269.083 1,069.746 158.016 263.469 62.487 78.616 µs 3.231 38.01
Server Jitter SHM(0) 0.174 0.541 0.978 4.154 12.678 23.758 77.020 11.700 23.217 5.226 5.393 µs 4.801 43.9
Server Offset 2001:470:e815::8 (spidey.rellim.com) -4.928 -1.612 -0.900 0.440 1.970 2.850 4.025 2.870 4.462 0.909 0.478 ms -0.02252 4.136
Server Offset 204.17.205.1 -4.426 -1.627 -0.190 1.090 2.121 2.925 3.039 2.311 4.552 0.781 1.032 ms -1.802 13.41
Server Offset 204.17.205.24 -79.547 -29.486 -11.422 0.079 2.626 6.355 35.035 14.048 35.841 5.772 -1.209 ms -4.119 29.76
Server Offset 204.17.205.27 -6.826 -5.445 -1.317 0.198 1.720 4.147 5.297 3.038 9.592 1.189 0.154 ms -0.969 13.24
Server Offset SHM(0) -97.647 -47.865 -28.104 -2.198 46.524 78.976 151.507 74.628 126.841 23.902 0.068 µs 1.5 9.33
Temp /dev/sda 40.000 40.000 40.000 41.000 42.000 43.000 49.000 2.000 3.000 0.805 41.427 °C
Temp /dev/sdb 51.000 51.000 51.000 53.000 59.000 60.000 60.000 8.000 9.000 2.120 53.207 °C
Temp /dev/sdc 51.000 51.000 51.000 53.000 53.000 54.000 56.000 2.000 3.000 0.587 52.917 °C
Temp /dev/sdd 58.000 58.000 58.000 60.000 68.000 69.000 69.000 10.000 11.000 2.620 60.298 °C
Temp /dev/sde 40.000 40.000 41.000 42.000 43.000 43.000 43.000 2.000 3.000 0.595 41.676 °C
Temp /dev/sdf 52.000 52.000 52.000 53.000 60.000 61.000 62.000 8.000 9.000 2.163 53.715 °C
Temp LM0 24.750 25.000 25.500 26.750 27.750 30.250 47.500 2.250 5.250 1.208 26.808 °C
Temp LM1 37.000 38.000 38.500 40.000 41.500 41.500 43.000 3.000 3.500 0.841 40.137 °C
Temp LM10 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM11 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM12 40.000 40.000 40.000 41.000 42.000 43.000 49.000 2.000 3.000 0.805 41.427 °C
Temp LM13 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp LM14 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Temp LM15 26.000 26.250 26.750 28.000 29.250 31.500 37.500 2.500 5.250 0.971 28.182 °C
Temp LM16 52.000 52.000 52.000 53.000 60.000 61.000 62.000 8.000 9.000 2.182 53.796 °C
Temp LM17 55.500 56.000 56.500 58.000 59.000 62.500 63.500 2.500 6.500 1.028 57.948 °C
Temp LM18 58.000 58.000 58.000 60.000 68.000 69.000 69.000 10.000 11.000 2.629 60.411 °C
Temp LM19 51.000 51.000 51.000 53.000 59.000 60.000 60.000 8.000 9.000 2.129 53.284 °C
Temp LM2 40.000 40.000 41.000 42.000 43.000 43.000 43.000 2.000 3.000 0.593 41.672 °C
Temp LM20 23.000 23.000 24.000 26.000 27.000 30.000 98.000 3.000 7.000 3.171 25.870 °C
Temp LM21 21.000 23.000 24.000 25.000 27.000 29.000 98.000 3.000 6.000 3.064 25.683 °C
Temp LM22 19.000 20.000 21.000 23.000 25.000 28.000 94.000 4.000 8.000 2.870 23.133 °C
Temp LM23 20.000 22.000 22.000 24.000 26.000 29.000 93.000 4.000 7.000 2.929 24.369 °C
Temp LM24 22.000 22.000 23.000 25.000 26.000 29.000 89.000 3.000 7.000 2.700 24.929 °C
Temp LM3 29.000 29.000 30.000 31.000 32.000 32.000 37.000 2.000 3.000 0.831 30.920 °C
Temp LM4 27.000 27.500 28.000 30.000 31.500 32.000 33.500 3.500 4.500 1.052 30.071 °C
Temp LM5 24.000 24.000 24.000 24.000 24.000 24.000 24.000 0.000 0.000 0.000 24.000 °C
Temp LM6 29.000 29.000 29.000 29.000 29.000 29.000 29.000 0.000 0.000 0.000 29.000 °C
Temp LM7 56.000 56.000 56.000 58.000 59.000 62.000 63.000 3.000 6.000 1.070 57.682 °C
Temp LM8 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM9 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp ZONE0 22.000 23.000 24.000 25.000 27.000 30.000 100.000 3.000 7.000 3.222 25.651 °C
Temp ZONE1 27.800 27.800 27.800 27.800 27.800 27.800 27.800 0.000 0.000 0.000 27.800 °C
Temp ZONE2 55.500 56.000 56.500 58.000 59.000 62.500 64.000 2.500 6.500 1.031 57.945 °C
Temp ZONE3 29.800 29.800 29.800 29.800 29.800 29.800 29.800 0.000 0.000 0.000 29.800 °C
Summary as CSV file


This server:

CPU: Quad core Intel Xeon E3-1241 v3
Kernel: config.gz
Motherboard: Supermicro X10SAE
OS: Gentoo stable
GPS; Meinberg GPS180PEX
GPS/PPS server: gpsd
NTP server: NTPsec
ntp.conf: current
ntp.log: current

Notes:

Notes:
03:20Z 20 Dec 2018 Change poll from 8s to 4s.  4s seems best.
01:30Z 20 Dec 2018 Change poll from 2s to 8s.
23:00Z 20 Dec 2018 Change poll from 4s to 2s.
22:00Z 20 Dec 2018 Change poll from 64s to 4s.
21:40  19 Dec 2018 -- just started

Poll:
64s   SHM(0) offset StdDev 34.5 us, jitter 5.3 us
8s    8s better jitter than 4s, but worse offset than 4s
4s    SHM(0) offset mean 0 ns StdDev 481 ns, jitter 449 ns StdDev 250 ns
      better than 2s, almost unstable
2s    




Glossary:

frequency offset:
The difference between the ntpd calculated frequency and the local system clock frequency (usually in parts per million, ppm)
jitter, dispersion:
The short term change in a value. NTP measures Local Time Jitter, Refclock Jitter, and Server Jitter in seconds. Local Frequency Jitter is in ppm or ppb.
ms, millisecond:
One thousandth of a second = 0.001 seconds, 1e-3 seconds
mu, mean:
The arithmetic mean: the sum of all the values divided by the number of values. The formula for mu is: "mu = (∑xi) / N". Where xi denotes the data points and N is the number of data points.
ns, nanosecond:
One billionth of a second, also one thousandth of a microsecond, 0.000000001 seconds and 1e-9 seconds.
percentile:
The value below which a given percentage of values fall.
ppb, parts per billion:
Ratio between two values. These following are all the same: 1 ppb, one in one billion, 1/1,000,000,000, 0.000,000,001, 1e-9 and 0.000,000,1%
ppm, parts per million:
Ratio between two values. These following are all the same: 1 ppm, one in one million, 1/1,000,000, 0.000,001, and 0.000,1%
‰, parts per thousand:
Ratio between two values. These following are all the same: 1 ‰. one in one thousand, 1/1,000, 0.001, and 0.1%
refclock:
Reference clock, a local GPS module or other local source of time.
remote clock:
Any clock reached over the network, LAN or WAN. Also called a peer or server.
time offset:
The difference between the ntpd calculated time and the local system clock's time. Also called phase offset.
σ, sigma:
Sigma denotes the standard deviation (SD) and is centered on the arithmetic mean of the data set. The SD is simply the square root of the variance of the data set. Two sigma is simply twice the standard deviation. Three sigma is three times sigma. Smaller is better.
The formula for sigma is: "σ = √[ ∑(xi-mu)^2 / N ]". Where xi denotes the data points and N is the number of data points.
Skewness, Skew:
The skewness of a random variable X is the third standardized moment and is a dimension-less ratio. ntpviz uses the FIsher-Pearson moment of skewness. There are other different ways to calculate Skewness Wikipedia describes Skewness best: "The qualitative interpretation of the skew is complicated and unintuitive."
A normal distribution has a skewness of zero.
Kurtosis, Kurt:
The kurtosis of a random variable X is the fourth standardized moment and is a dimension-less ratio. ntpviz uses standard Kurtosis. There are other different ways to calculate Kurtosis.
A normal distribution has a Kurtosis of three. NIST describes a kurtosis over three as "heavy tailed" and one under three as "light tailed".
upstream clock:
Any server or reference clock used as a source of time.
µs, us, microsecond:
One millionth of a second, also one thousandth of a millisecond, 0.000,001 seconds, and 1e-6 seconds.



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