NTPsec

Backup/Meinberg

Report generated: Thu Aug 6 15:43:01 2026 UTC
Start Time: Thu Jul 30 15:43:00 2026 UTC
End Time: Thu Aug 6 15:43:00 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 -110.833 -59.982 -22.738 -2.903 30.626 87.085 3,331.515 53.364 147.067 86.988 3.519 µs 23.14 651.9
Local Clock Frequency Offset 1.120 1.123 1.271 1.631 12.943 13.249 13.320 11.672 12.126 4.707 4.094 ppm 1.304 2.714

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 0.356 0.417 0.475 0.771 47.706 68.933 1,177.868 47.231 68.516 52.005 12.094 µs 15.75 297.5

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 0.000 0.089 0.142 0.728 25.036 39.583 892.406 24.894 39.494 37.903 7.267 ppb 15.95 290.5

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 -110.833 -59.982 -22.738 -2.903 30.626 87.085 3,331.515 53.364 147.067 86.988 3.519 µs 23.14 651.9

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 1.120 1.123 1.271 1.631 12.943 13.249 13.320 11.672 12.126 4.707 4.094 ppm 1.304 2.714
Temp /dev/sda 65.000 65.000 66.000 67.000 70.000 71.000 73.000 4.000 6.000 1.368 67.618 °C
Temp /dev/sdb 46.000 46.000 47.000 49.000 55.000 55.000 56.000 8.000 9.000 2.387 49.717 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 63.000 65.000 65.000 5.000 7.000 1.614 60.376 °C
Temp /dev/sdd 70.000 70.000 71.000 73.000 78.000 79.000 80.000 7.000 9.000 1.952 73.551 °C
Temp /dev/sde 50.000 50.000 51.000 53.000 59.000 60.000 61.000 8.000 10.000 2.455 53.385 °C
Temp /dev/sdf 48.000 48.000 48.000 50.000 56.000 58.000 58.000 8.000 10.000 2.336 51.066 °C
Temp LM0 29.750 29.750 30.500 33.500 55.000 58.000 58.000 24.500 28.250 9.846 40.169 °C
Temp LM1 43.500 43.500 44.000 46.000 68.500 69.500 70.000 24.500 26.000 10.198 53.578 °C
Temp LM10 0.000 0.000 0.000 0.000 27.800 27.800 27.800 27.800 27.800 13.626 11.153 °C
Temp LM11 0.000 0.000 0.000 0.000 34.500 35.500 35.750 34.500 35.500 15.931 13.020 °C
Temp LM12 0.000 0.000 0.000 0.000 46.000 46.500 47.000 46.000 46.500 22.267 18.223 °C
Temp LM13 27.800 27.800 27.800 27.800 58.000 61.000 61.000 30.200 33.200 13.130 38.462 °C
Temp LM14 29.800 29.800 29.800 29.800 37.000 38.000 38.000 7.200 8.200 3.122 32.316 °C
Temp LM15 31.000 31.000 31.750 34.000 37.000 37.500 38.250 5.250 6.500 1.431 34.075 °C
Temp LM16 24.000 24.000 24.000 49.000 55.000 56.000 57.000 31.000 32.000 13.102 39.895 °C
Temp LM17 28.500 29.000 29.500 63.500 66.000 66.000 67.500 36.500 37.000 16.432 51.293 °C
Temp LM18 0.000 0.000 0.000 0.000 68.000 69.000 70.000 68.000 69.000 32.214 26.348 °C
Temp LM19 0.000 0.000 0.000 48.000 53.000 55.000 55.000 53.000 55.000 24.052 29.328 °C
Temp LM2 0.000 0.000 0.000 51.000 57.000 59.000 60.000 57.000 59.000 25.935 31.618 °C
Temp LM20 0.000 0.000 0.000 30.000 33.000 35.000 73.000 33.000 35.000 15.723 18.957 °C
Temp LM21 0.000 0.000 0.000 30.000 33.000 36.000 72.000 33.000 36.000 15.622 18.862 °C
Temp LM22 0.000 0.000 0.000 28.000 31.000 33.000 69.000 31.000 33.000 14.679 17.689 °C
Temp LM23 0.000 0.000 0.000 29.000 32.000 35.000 72.000 32.000 35.000 15.212 18.369 °C
Temp LM24 26.000 27.000 28.000 29.800 32.000 33.000 67.000 4.000 6.000 2.016 30.169 °C
Temp LM3 31.250 31.500 32.000 35.750 38.000 38.000 40.000 6.000 6.500 1.745 35.270 °C
Temp LM4 32.000 32.000 33.000 36.500 54.000 55.000 56.000 21.000 23.000 7.987 41.432 °C
Temp LM5 24.000 24.000 24.000 24.000 34.000 35.000 47.000 10.000 11.000 3.858 27.050 °C
Temp LM6 28.000 28.500 29.000 31.000 34.000 36.000 71.500 5.000 7.500 2.667 31.341 °C
Temp LM7 25.000 27.000 28.000 63.000 66.000 66.000 67.000 38.000 39.000 17.324 50.353 °C
Temp LM8 0.000 0.000 0.000 0.000 33.000 34.000 48.000 33.000 34.000 15.100 12.325 °C
Temp LM9 0.000 0.000 0.000 0.000 32.000 33.000 41.000 32.000 33.000 14.995 12.255 °C
Temp ZONE0 27.000 28.000 29.000 31.000 34.000 37.000 72.000 5.000 9.000 2.689 31.525 °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 62.500 63.000 63.000 65.000 68.500 69.500 70.500 5.500 6.500 1.588 65.192 °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) -550.613 -394.133 -230.340 20.751 158.985 208.668 3,106.044 389.325 602.801 162.576 7.932 µs 5.755 93.46

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 -2.976 -0.895 -0.367 0.053 0.484 1.749 3.134 0.852 2.644 0.412 0.045 ms -0.09798 19.16

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 -149.286 -96.386 -45.698 35.276 85.635 165.577 3,331.515 131.333 261.963 134.525 37.678 µs 15.27 292.5

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 -1,339.632 -117.351 -49.520 34.535 101.404 206.507 3,334.266 150.924 323.858 124.091 34.898 µs 14.4 320.6

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) -53.803 -21.094 -16.850 -3.141 20.012 71.214 186.467 36.862 92.308 16.786 -0.420 µs 3.765 32.08

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) 0.000 3.872 5.858 26.420 88.608 125.674 2,242.345 82.750 121.802 64.087 37.362 µs 19.87 578

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 0.000 5.789 9.488 22.647 51.425 125.496 2,230.236 41.937 119.707 50.617 28.197 µs 27.25 1010

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 0.000 3.574 5.929 23.351 61.054 98.686 2,317.171 55.125 95.112 64.830 29.167 µs 24.93 760.8

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 0.000 9.290 19.534 113.406 178.806 216.199 2,184.033 159.272 206.909 66.024 108.057 µs 9.413 257.7

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) 0.105 0.312 0.470 1.496 5.111 31.762 85.596 4.641 31.450 5.193 2.527 µs 7.886 82.11

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 1.120 1.123 1.271 1.631 12.943 13.249 13.320 11.672 12.126 4.707 4.094 ppm 1.304 2.714
Local Clock Time Offset -110.833 -59.982 -22.738 -2.903 30.626 87.085 3,331.515 53.364 147.067 86.988 3.519 µs 23.14 651.9
Local RMS Frequency Jitter 0.000 0.089 0.142 0.728 25.036 39.583 892.406 24.894 39.494 37.903 7.267 ppb 15.95 290.5
Local RMS Time Jitter 0.356 0.417 0.475 0.771 47.706 68.933 1,177.868 47.231 68.516 52.005 12.094 µs 15.75 297.5
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 0.000 3.872 5.858 26.420 88.608 125.674 2,242.345 82.750 121.802 64.087 37.362 µs 19.87 578
Server Jitter 204.17.205.1 0.000 5.789 9.488 22.647 51.425 125.496 2,230.236 41.937 119.707 50.617 28.197 µs 27.25 1010
Server Jitter 204.17.205.24 0.000 3.574 5.929 23.351 61.054 98.686 2,317.171 55.125 95.112 64.830 29.167 µs 24.93 760.8
Server Jitter 204.17.205.27 0.000 9.290 19.534 113.406 178.806 216.199 2,184.033 159.272 206.909 66.024 108.057 µs 9.413 257.7
Server Jitter SHM(0) 0.105 0.312 0.470 1.496 5.111 31.762 85.596 4.641 31.450 5.193 2.527 µs 7.886 82.11
Server Offset 2001:470:e815::8 (spidey.rellim.com) -550.613 -394.133 -230.340 20.751 158.985 208.668 3,106.044 389.325 602.801 162.576 7.932 µs 5.755 93.46
Server Offset 204.17.205.1 -2.976 -0.895 -0.367 0.053 0.484 1.749 3.134 0.852 2.644 0.412 0.045 ms -0.09798 19.16
Server Offset 204.17.205.24 -149.286 -96.386 -45.698 35.276 85.635 165.577 3,331.515 131.333 261.963 134.525 37.678 µs 15.27 292.5
Server Offset 204.17.205.27 -1,339.632 -117.351 -49.520 34.535 101.404 206.507 3,334.266 150.924 323.858 124.091 34.898 µs 14.4 320.6
Server Offset SHM(0) -53.803 -21.094 -16.850 -3.141 20.012 71.214 186.467 36.862 92.308 16.786 -0.420 µs 3.765 32.08
Temp /dev/sda 65.000 65.000 66.000 67.000 70.000 71.000 73.000 4.000 6.000 1.368 67.618 °C
Temp /dev/sdb 46.000 46.000 47.000 49.000 55.000 55.000 56.000 8.000 9.000 2.387 49.717 °C
Temp /dev/sdc 58.000 58.000 58.000 60.000 63.000 65.000 65.000 5.000 7.000 1.614 60.376 °C
Temp /dev/sdd 70.000 70.000 71.000 73.000 78.000 79.000 80.000 7.000 9.000 1.952 73.551 °C
Temp /dev/sde 50.000 50.000 51.000 53.000 59.000 60.000 61.000 8.000 10.000 2.455 53.385 °C
Temp /dev/sdf 48.000 48.000 48.000 50.000 56.000 58.000 58.000 8.000 10.000 2.336 51.066 °C
Temp LM0 29.750 29.750 30.500 33.500 55.000 58.000 58.000 24.500 28.250 9.846 40.169 °C
Temp LM1 43.500 43.500 44.000 46.000 68.500 69.500 70.000 24.500 26.000 10.198 53.578 °C
Temp LM10 0.000 0.000 0.000 0.000 27.800 27.800 27.800 27.800 27.800 13.626 11.153 °C
Temp LM11 0.000 0.000 0.000 0.000 34.500 35.500 35.750 34.500 35.500 15.931 13.020 °C
Temp LM12 0.000 0.000 0.000 0.000 46.000 46.500 47.000 46.000 46.500 22.267 18.223 °C
Temp LM13 27.800 27.800 27.800 27.800 58.000 61.000 61.000 30.200 33.200 13.130 38.462 °C
Temp LM14 29.800 29.800 29.800 29.800 37.000 38.000 38.000 7.200 8.200 3.122 32.316 °C
Temp LM15 31.000 31.000 31.750 34.000 37.000 37.500 38.250 5.250 6.500 1.431 34.075 °C
Temp LM16 24.000 24.000 24.000 49.000 55.000 56.000 57.000 31.000 32.000 13.102 39.895 °C
Temp LM17 28.500 29.000 29.500 63.500 66.000 66.000 67.500 36.500 37.000 16.432 51.293 °C
Temp LM18 0.000 0.000 0.000 0.000 68.000 69.000 70.000 68.000 69.000 32.214 26.348 °C
Temp LM19 0.000 0.000 0.000 48.000 53.000 55.000 55.000 53.000 55.000 24.052 29.328 °C
Temp LM2 0.000 0.000 0.000 51.000 57.000 59.000 60.000 57.000 59.000 25.935 31.618 °C
Temp LM20 0.000 0.000 0.000 30.000 33.000 35.000 73.000 33.000 35.000 15.723 18.957 °C
Temp LM21 0.000 0.000 0.000 30.000 33.000 36.000 72.000 33.000 36.000 15.622 18.862 °C
Temp LM22 0.000 0.000 0.000 28.000 31.000 33.000 69.000 31.000 33.000 14.679 17.689 °C
Temp LM23 0.000 0.000 0.000 29.000 32.000 35.000 72.000 32.000 35.000 15.212 18.369 °C
Temp LM24 26.000 27.000 28.000 29.800 32.000 33.000 67.000 4.000 6.000 2.016 30.169 °C
Temp LM3 31.250 31.500 32.000 35.750 38.000 38.000 40.000 6.000 6.500 1.745 35.270 °C
Temp LM4 32.000 32.000 33.000 36.500 54.000 55.000 56.000 21.000 23.000 7.987 41.432 °C
Temp LM5 24.000 24.000 24.000 24.000 34.000 35.000 47.000 10.000 11.000 3.858 27.050 °C
Temp LM6 28.000 28.500 29.000 31.000 34.000 36.000 71.500 5.000 7.500 2.667 31.341 °C
Temp LM7 25.000 27.000 28.000 63.000 66.000 66.000 67.000 38.000 39.000 17.324 50.353 °C
Temp LM8 0.000 0.000 0.000 0.000 33.000 34.000 48.000 33.000 34.000 15.100 12.325 °C
Temp LM9 0.000 0.000 0.000 0.000 32.000 33.000 41.000 32.000 33.000 14.995 12.255 °C
Temp ZONE0 27.000 28.000 29.000 31.000 34.000 37.000 72.000 5.000 9.000 2.689 31.525 °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 62.500 63.000 63.000 65.000 68.500 69.500 70.500 5.500 6.500 1.588 65.192 °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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