NTPsec

Backup/Meinberg

Report generated: Mon Sep 21 20:33:00 2026 UTC
Start Time: Sun Sep 20 20:33:00 2026 UTC
End Time: Mon Sep 21 20:33:00 2026 UTC
Report Period: 1.0 days
Warning: plots clipped

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 -96.827 -92.342 -45.915 -3.333 73.639 145.514 227.010 119.554 237.856 37.356 3.444 µs 1.679 10.08
Local Clock Frequency Offset 11.400 11.413 11.459 11.637 12.107 12.240 12.255 0.649 0.827 0.194 11.668 ppm 1.069 3.798

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 0.455 0.485 0.557 0.863 4.054 9.401 12.764 3.497 8.916 1.594 1.299 µs 4.303 23.1

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 0.133 0.175 0.267 0.824 5.408 8.308 10.118 5.141 8.133 1.671 1.386 ppb 2.695 9.912

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 -96.827 -92.342 -45.915 -3.333 73.639 145.514 227.010 119.554 237.856 37.356 3.444 µs 1.679 10.08

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 11.400 11.413 11.459 11.637 12.107 12.240 12.255 0.649 0.827 0.194 11.668 ppm 1.069 3.798
Temp /dev/sda 65.000 65.000 66.000 67.000 68.000 70.000 78.000 2.000 5.000 1.137 66.780 °C
Temp /dev/sdb 46.000 46.000 47.000 47.000 48.000 49.000 50.000 1.000 3.000 0.631 47.432 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 60.000 61.000 65.000 2.000 3.000 0.907 59.718 °C
Temp /dev/sdd 70.000 70.000 70.000 71.000 73.000 74.000 76.000 3.000 4.000 0.830 71.491 °C
Temp /dev/sde 50.000 50.000 50.000 52.000 54.000 54.000 54.000 4.000 4.000 1.095 52.390 °C
Temp /dev/sdf 48.000 48.000 48.000 49.000 50.000 51.000 52.000 2.000 3.000 0.735 48.847 °C
Temp LM0 29.750 29.750 29.750 30.750 40.000 41.000 43.000 10.250 11.250 2.527 31.400 °C
Temp LM1 41.500 42.000 42.000 43.000 45.500 46.500 46.500 3.500 4.500 1.021 43.075 °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 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °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 31.000 31.000 31.000 32.250 37.500 38.500 39.500 6.500 7.500 1.631 32.468 °C
Temp LM16 48.000 48.000 48.000 49.000 50.000 51.000 52.000 2.000 3.000 0.762 48.913 °C
Temp LM17 61.500 62.000 62.000 62.500 66.000 66.000 67.000 4.000 4.000 0.961 62.984 °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 46.000 46.000 47.000 47.000 49.000 49.000 50.000 2.000 3.000 0.658 47.432 °C
Temp LM2 50.000 50.000 50.000 53.000 54.000 54.000 54.000 4.000 4.000 1.114 52.422 °C
Temp LM20 28.000 28.000 29.000 30.000 60.000 71.000 73.000 31.000 43.000 8.569 32.596 °C
Temp LM21 27.000 28.000 28.000 30.000 53.000 69.000 73.000 25.000 41.000 7.753 32.091 °C
Temp LM22 25.000 25.000 26.000 28.000 55.000 67.000 70.000 29.000 42.000 8.221 30.059 °C
Temp LM23 27.000 28.000 28.000 29.000 57.000 67.000 71.000 29.000 39.000 7.838 31.596 °C
Temp LM24 26.000 27.000 27.000 29.000 51.000 64.000 70.000 24.000 37.000 6.857 30.331 °C
Temp LM3 34.000 34.000 34.000 35.000 40.000 40.000 41.000 6.000 6.000 1.425 35.031 °C
Temp LM4 32.500 32.500 32.500 34.000 36.500 37.500 37.500 4.000 5.000 1.211 34.085 °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 28.000 28.500 29.000 30.000 59.500 70.500 74.000 30.500 42.000 8.562 32.267 °C
Temp LM7 61.000 62.000 62.000 62.000 65.000 66.000 67.000 3.000 4.000 0.986 62.655 °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 28.000 28.000 29.000 30.000 60.000 71.000 73.000 31.000 43.000 8.496 32.467 °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 61.500 62.000 62.000 62.500 65.500 66.000 67.000 3.500 4.000 0.958 62.965 °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) -1,009.659 -925.887 -594.988 32.224 355.382 626.714 780.832 950.370 1,552.601 251.511 13.018 µs -1.502 8.393

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 -743.760 -580.379 -240.169 75.820 266.509 306.659 374.464 506.678 887.038 188.497 34.125 µs -0.7124 3.515

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 -95.750 -63.670 -32.829 54.495 136.482 219.459 265.579 169.311 283.129 47.625 52.412 µs 0.7426 6.262

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 -396.314 -171.231 -31.454 45.976 114.849 180.628 422.800 146.303 351.859 60.646 42.554 µs -0.3256 21.91

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) -96.828 -92.343 -45.916 -3.334 73.640 145.515 227.011 119.556 237.858 37.357 3.444 µs 1.679 10.08

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) 1.060 3.326 4.994 23.762 95.482 120.850 157.786 90.488 117.524 30.893 35.420 µs 1.028 3.295

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 2.097 5.600 9.302 21.654 44.947 86.185 120.345 35.645 80.585 13.349 24.214 µs 2.655 15.59

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 1.754 2.719 4.650 22.341 52.491 91.298 108.502 47.841 88.579 16.878 24.016 µs 1.993 8.819

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 4.734 7.186 15.686 86.451 144.090 165.440 198.346 128.404 158.254 39.986 82.731 µs -0.115 2.363

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) 0.243 0.392 0.598 1.953 11.632 49.649 71.463 11.034 49.257 7.945 3.917 µs 5.257 33.31

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 11.400 11.413 11.459 11.637 12.107 12.240 12.255 0.649 0.827 0.194 11.668 ppm 1.069 3.798
Local Clock Time Offset -96.827 -92.342 -45.915 -3.333 73.639 145.514 227.010 119.554 237.856 37.356 3.444 µs 1.679 10.08
Local RMS Frequency Jitter 0.133 0.175 0.267 0.824 5.408 8.308 10.118 5.141 8.133 1.671 1.386 ppb 2.695 9.912
Local RMS Time Jitter 0.455 0.485 0.557 0.863 4.054 9.401 12.764 3.497 8.916 1.594 1.299 µs 4.303 23.1
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 1.060 3.326 4.994 23.762 95.482 120.850 157.786 90.488 117.524 30.893 35.420 µs 1.028 3.295
Server Jitter 204.17.205.1 2.097 5.600 9.302 21.654 44.947 86.185 120.345 35.645 80.585 13.349 24.214 µs 2.655 15.59
Server Jitter 204.17.205.24 1.754 2.719 4.650 22.341 52.491 91.298 108.502 47.841 88.579 16.878 24.016 µs 1.993 8.819
Server Jitter 204.17.205.27 4.734 7.186 15.686 86.451 144.090 165.440 198.346 128.404 158.254 39.986 82.731 µs -0.115 2.363
Server Jitter SHM(0) 0.243 0.392 0.598 1.953 11.632 49.649 71.463 11.034 49.257 7.945 3.917 µs 5.257 33.31
Server Offset 2001:470:e815::8 (spidey.rellim.com) -1,009.659 -925.887 -594.988 32.224 355.382 626.714 780.832 950.370 1,552.601 251.511 13.018 µs -1.502 8.393
Server Offset 204.17.205.1 -743.760 -580.379 -240.169 75.820 266.509 306.659 374.464 506.678 887.038 188.497 34.125 µs -0.7124 3.515
Server Offset 204.17.205.24 -95.750 -63.670 -32.829 54.495 136.482 219.459 265.579 169.311 283.129 47.625 52.412 µs 0.7426 6.262
Server Offset 204.17.205.27 -396.314 -171.231 -31.454 45.976 114.849 180.628 422.800 146.303 351.859 60.646 42.554 µs -0.3256 21.91
Server Offset SHM(0) -96.828 -92.343 -45.916 -3.334 73.640 145.515 227.011 119.556 237.858 37.357 3.444 µs 1.679 10.08
Temp /dev/sda 65.000 65.000 66.000 67.000 68.000 70.000 78.000 2.000 5.000 1.137 66.780 °C
Temp /dev/sdb 46.000 46.000 47.000 47.000 48.000 49.000 50.000 1.000 3.000 0.631 47.432 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 60.000 61.000 65.000 2.000 3.000 0.907 59.718 °C
Temp /dev/sdd 70.000 70.000 70.000 71.000 73.000 74.000 76.000 3.000 4.000 0.830 71.491 °C
Temp /dev/sde 50.000 50.000 50.000 52.000 54.000 54.000 54.000 4.000 4.000 1.095 52.390 °C
Temp /dev/sdf 48.000 48.000 48.000 49.000 50.000 51.000 52.000 2.000 3.000 0.735 48.847 °C
Temp LM0 29.750 29.750 29.750 30.750 40.000 41.000 43.000 10.250 11.250 2.527 31.400 °C
Temp LM1 41.500 42.000 42.000 43.000 45.500 46.500 46.500 3.500 4.500 1.021 43.075 °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 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 °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 31.000 31.000 31.000 32.250 37.500 38.500 39.500 6.500 7.500 1.631 32.468 °C
Temp LM16 48.000 48.000 48.000 49.000 50.000 51.000 52.000 2.000 3.000 0.762 48.913 °C
Temp LM17 61.500 62.000 62.000 62.500 66.000 66.000 67.000 4.000 4.000 0.961 62.984 °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 46.000 46.000 47.000 47.000 49.000 49.000 50.000 2.000 3.000 0.658 47.432 °C
Temp LM2 50.000 50.000 50.000 53.000 54.000 54.000 54.000 4.000 4.000 1.114 52.422 °C
Temp LM20 28.000 28.000 29.000 30.000 60.000 71.000 73.000 31.000 43.000 8.569 32.596 °C
Temp LM21 27.000 28.000 28.000 30.000 53.000 69.000 73.000 25.000 41.000 7.753 32.091 °C
Temp LM22 25.000 25.000 26.000 28.000 55.000 67.000 70.000 29.000 42.000 8.221 30.059 °C
Temp LM23 27.000 28.000 28.000 29.000 57.000 67.000 71.000 29.000 39.000 7.838 31.596 °C
Temp LM24 26.000 27.000 27.000 29.000 51.000 64.000 70.000 24.000 37.000 6.857 30.331 °C
Temp LM3 34.000 34.000 34.000 35.000 40.000 40.000 41.000 6.000 6.000 1.425 35.031 °C
Temp LM4 32.500 32.500 32.500 34.000 36.500 37.500 37.500 4.000 5.000 1.211 34.085 °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 28.000 28.500 29.000 30.000 59.500 70.500 74.000 30.500 42.000 8.562 32.267 °C
Temp LM7 61.000 62.000 62.000 62.000 65.000 66.000 67.000 3.000 4.000 0.986 62.655 °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 28.000 28.000 29.000 30.000 60.000 71.000 73.000 31.000 43.000 8.496 32.467 °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 61.500 62.000 62.000 62.500 65.500 66.000 67.000 3.500 4.000 0.958 62.965 °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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