NTPsec

Backup/Meinberg

Report generated: Mon Jun 22 15:43:01 2026 UTC
Start Time: Mon Jun 15 15:43:01 2026 UTC
End Time: Mon Jun 22 15:43:01 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 -91.245 -52.098 -20.119 -2.721 23.213 116.726 208.597 43.332 168.824 22.932 0.261 µs 3.103 22.74
Local Clock Frequency Offset 6.730 6.742 6.757 7.128 7.436 7.504 7.522 0.679 0.762 0.200 7.111 ppm -0.1016 2.096

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 0.318 0.412 0.479 0.760 3.644 9.602 14.318 3.165 9.190 1.576 1.189 µs 4.453 24.36

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 0.038 0.075 0.118 0.584 2.612 6.743 10.398 2.494 6.668 1.107 0.858 ppb 4.25 25.17

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 -91.245 -52.098 -20.119 -2.721 23.213 116.726 208.597 43.332 168.824 22.932 0.261 µs 3.103 22.74

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 6.730 6.742 6.757 7.128 7.436 7.504 7.522 0.679 0.762 0.200 7.111 ppm -0.1016 2.096
Temp /dev/sda 45.000 45.000 45.000 47.000 56.000 59.000 59.000 11.000 14.000 2.796 47.338 °C
Temp /dev/sdb 47.000 47.000 47.000 49.000 53.000 55.000 55.000 6.000 8.000 1.751 49.099 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 63.000 67.000 67.000 5.000 9.000 1.479 60.579 °C
Temp /dev/sdd 71.000 71.000 71.000 73.000 77.000 78.000 82.000 6.000 7.000 1.539 73.138 °C
Temp /dev/sde 50.000 51.000 51.000 53.000 59.000 60.000 60.000 8.000 9.000 2.061 53.297 °C
Temp /dev/sdf 48.000 48.000 48.000 50.000 55.000 56.000 56.000 7.000 8.000 1.823 50.482 °C
Temp LM0 29.250 29.500 29.500 31.500 33.750 37.250 43.000 4.250 7.750 1.463 31.665 °C
Temp LM1 43.000 43.500 43.500 45.500 46.500 47.000 47.500 3.000 3.500 0.917 45.193 °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 45.000 45.000 45.000 47.000 56.000 59.000 59.000 11.000 14.000 2.802 47.338 °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 30.500 30.750 31.000 33.000 35.000 36.000 39.250 4.000 5.250 1.245 32.907 °C
Temp LM16 48.000 48.000 48.000 50.000 55.000 56.000 56.000 7.000 8.000 1.833 50.535 °C
Temp LM17 61.000 61.000 61.000 63.000 64.500 67.500 69.500 3.500 6.500 1.223 62.848 °C
Temp LM18 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM19 47.000 47.000 47.000 49.000 53.000 55.000 55.000 6.000 8.000 1.752 49.116 °C
Temp LM2 51.000 51.000 51.000 53.000 59.000 60.000 61.000 8.000 9.000 2.075 53.339 °C
Temp LM20 28.000 28.000 29.000 31.000 34.000 56.000 76.000 5.000 28.000 4.022 31.270 °C
Temp LM21 27.000 28.000 28.000 31.000 34.000 50.000 76.000 6.000 22.000 3.684 31.016 °C
Temp LM22 25.000 26.000 26.000 29.000 32.000 51.000 73.000 6.000 25.000 3.796 29.029 °C
Temp LM23 26.000 27.000 28.000 30.000 33.000 51.000 73.000 5.000 24.000 3.672 30.155 °C
Temp LM24 26.000 27.000 28.000 30.000 33.000 50.000 68.000 5.000 23.000 3.348 30.153 °C
Temp LM3 34.000 34.000 34.000 36.000 37.000 38.000 41.000 3.000 4.000 1.003 35.767 °C
Temp LM4 32.000 32.000 32.500 34.500 36.500 36.500 37.000 4.000 4.500 1.248 34.497 °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 27.500 28.000 28.500 30.500 33.500 55.000 73.500 5.000 27.000 3.927 30.890 °C
Temp LM7 61.000 61.000 61.000 63.000 64.000 67.000 69.000 3.000 6.000 1.210 62.553 °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 27.000 28.000 29.000 31.000 34.000 55.000 76.000 5.000 27.000 3.994 31.123 °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 61.000 61.000 61.000 62.500 64.500 67.500 69.500 3.500 6.500 1.223 62.854 °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) -753.324 -495.898 -218.797 33.997 184.616 223.535 245.457 403.413 719.433 136.935 8.309 µs -1.657 8.199

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 -1,046.456 -549.109 -427.861 13.374 322.474 535.918 654.739 750.335 1,085.027 230.030 -3.449 µs -0.4018 4.016

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 -96.073 -44.525 -14.391 43.149 82.962 159.643 262.269 97.353 204.168 34.252 41.145 µs 0.7031 7.888

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 -526.982 -179.688 -20.367 43.042 106.565 246.146 482.205 126.932 425.834 59.429 42.009 µs -0.6869 26.17

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) -91.246 -52.099 -20.120 -2.722 23.214 116.727 208.598 43.334 168.826 22.932 0.260 µs 3.103 22.74

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) 1.835 3.856 6.092 20.716 71.483 95.003 302.085 65.391 91.147 23.253 28.533 µs 2.222 16.32

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 4.078 6.768 9.122 17.898 36.316 55.008 245.856 27.194 48.240 11.369 20.080 µs 5.635 71.73

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 0.001 0.004 0.007 0.023 0.052 0.078 31.891 0.045 0.073 0.494 0.034 ms 64.23 4143

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 2.838 5.985 10.244 67.067 136.052 166.653 261.433 125.808 160.668 41.689 65.311 µs 0.4923 2.724

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) 0.104 0.328 0.519 1.738 9.566 44.264 82.178 9.047 43.936 6.962 3.386 µs 5.737 40.76

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 6.730 6.742 6.757 7.128 7.436 7.504 7.522 0.679 0.762 0.200 7.111 ppm -0.1016 2.096
Local Clock Time Offset -91.245 -52.098 -20.119 -2.721 23.213 116.726 208.597 43.332 168.824 22.932 0.261 µs 3.103 22.74
Local RMS Frequency Jitter 0.038 0.075 0.118 0.584 2.612 6.743 10.398 2.494 6.668 1.107 0.858 ppb 4.25 25.17
Local RMS Time Jitter 0.318 0.412 0.479 0.760 3.644 9.602 14.318 3.165 9.190 1.576 1.189 µs 4.453 24.36
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 1.835 3.856 6.092 20.716 71.483 95.003 302.085 65.391 91.147 23.253 28.533 µs 2.222 16.32
Server Jitter 204.17.205.1 4.078 6.768 9.122 17.898 36.316 55.008 245.856 27.194 48.240 11.369 20.080 µs 5.635 71.73
Server Jitter 204.17.205.24 0.001 0.004 0.007 0.023 0.052 0.078 31.891 0.045 0.073 0.494 0.034 ms 64.23 4143
Server Jitter 204.17.205.27 2.838 5.985 10.244 67.067 136.052 166.653 261.433 125.808 160.668 41.689 65.311 µs 0.4923 2.724
Server Jitter SHM(0) 0.104 0.328 0.519 1.738 9.566 44.264 82.178 9.047 43.936 6.962 3.386 µs 5.737 40.76
Server Offset 2001:470:e815::8 (spidey.rellim.com) -753.324 -495.898 -218.797 33.997 184.616 223.535 245.457 403.413 719.433 136.935 8.309 µs -1.657 8.199
Server Offset 204.17.205.1 -1,046.456 -549.109 -427.861 13.374 322.474 535.918 654.739 750.335 1,085.027 230.030 -3.449 µs -0.4018 4.016
Server Offset 204.17.205.24 -96.073 -44.525 -14.391 43.149 82.962 159.643 262.269 97.353 204.168 34.252 41.145 µs 0.7031 7.888
Server Offset 204.17.205.27 -526.982 -179.688 -20.367 43.042 106.565 246.146 482.205 126.932 425.834 59.429 42.009 µs -0.6869 26.17
Server Offset SHM(0) -91.246 -52.099 -20.120 -2.722 23.214 116.727 208.598 43.334 168.826 22.932 0.260 µs 3.103 22.74
Temp /dev/sda 45.000 45.000 45.000 47.000 56.000 59.000 59.000 11.000 14.000 2.796 47.338 °C
Temp /dev/sdb 47.000 47.000 47.000 49.000 53.000 55.000 55.000 6.000 8.000 1.751 49.099 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 63.000 67.000 67.000 5.000 9.000 1.479 60.579 °C
Temp /dev/sdd 71.000 71.000 71.000 73.000 77.000 78.000 82.000 6.000 7.000 1.539 73.138 °C
Temp /dev/sde 50.000 51.000 51.000 53.000 59.000 60.000 60.000 8.000 9.000 2.061 53.297 °C
Temp /dev/sdf 48.000 48.000 48.000 50.000 55.000 56.000 56.000 7.000 8.000 1.823 50.482 °C
Temp LM0 29.250 29.500 29.500 31.500 33.750 37.250 43.000 4.250 7.750 1.463 31.665 °C
Temp LM1 43.000 43.500 43.500 45.500 46.500 47.000 47.500 3.000 3.500 0.917 45.193 °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 45.000 45.000 45.000 47.000 56.000 59.000 59.000 11.000 14.000 2.802 47.338 °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 30.500 30.750 31.000 33.000 35.000 36.000 39.250 4.000 5.250 1.245 32.907 °C
Temp LM16 48.000 48.000 48.000 50.000 55.000 56.000 56.000 7.000 8.000 1.833 50.535 °C
Temp LM17 61.000 61.000 61.000 63.000 64.500 67.500 69.500 3.500 6.500 1.223 62.848 °C
Temp LM18 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °C
Temp LM19 47.000 47.000 47.000 49.000 53.000 55.000 55.000 6.000 8.000 1.752 49.116 °C
Temp LM2 51.000 51.000 51.000 53.000 59.000 60.000 61.000 8.000 9.000 2.075 53.339 °C
Temp LM20 28.000 28.000 29.000 31.000 34.000 56.000 76.000 5.000 28.000 4.022 31.270 °C
Temp LM21 27.000 28.000 28.000 31.000 34.000 50.000 76.000 6.000 22.000 3.684 31.016 °C
Temp LM22 25.000 26.000 26.000 29.000 32.000 51.000 73.000 6.000 25.000 3.796 29.029 °C
Temp LM23 26.000 27.000 28.000 30.000 33.000 51.000 73.000 5.000 24.000 3.672 30.155 °C
Temp LM24 26.000 27.000 28.000 30.000 33.000 50.000 68.000 5.000 23.000 3.348 30.153 °C
Temp LM3 34.000 34.000 34.000 36.000 37.000 38.000 41.000 3.000 4.000 1.003 35.767 °C
Temp LM4 32.000 32.000 32.500 34.500 36.500 36.500 37.000 4.000 4.500 1.248 34.497 °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 27.500 28.000 28.500 30.500 33.500 55.000 73.500 5.000 27.000 3.927 30.890 °C
Temp LM7 61.000 61.000 61.000 63.000 64.000 67.000 69.000 3.000 6.000 1.210 62.553 °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 27.000 28.000 29.000 31.000 34.000 55.000 76.000 5.000 27.000 3.994 31.123 °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 61.000 61.000 61.000 62.500 64.500 67.500 69.500 3.500 6.500 1.223 62.854 °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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