[ntp:questions] Peer Review of ntpq -c rv

David Lord snews at lordynet.org
Wed Mar 7 20:51:25 UTC 2012


Alby VA wrote:
> On Mar 7, 11:59 am, David Lord <sn... at lordynet.org> wrote:
>> Alby VA wrote:
>>> On Mar 7, 10:59 am, David Lord <sn... at lordynet.org> wrote:
>>>> Alby VA wrote:
>>>>>  I'm looking to get a little feedback on if the following output of my
>>>>> Sure GPS / FreeBSD
>>>>> setup looks like its running smoothly and keeping time correctly.
>>>>> assID=0 status=0115 leap_none, sync_atomic, 1 event,
>>>>> event_clock_reset,
>>>>> version="ntpd 4.2.... at 1.2349-o Mon Feb 20 22:00:33 UTC 2012 (1)",
>>>>> processor="amd64", system="FreeBSD/9.0-RELEASE", leap=00, stratum=1,
>>>>> precision=-19, rootdelay=0.000, rootdisp=0.269, refid=PPS,
>>>>> reftime=d301d22f.dc1393c2  Wed, Mar  7 2012  7:25:19.859,
>>>>> clock=d301d230.cc08bad9  Wed, Mar  7 2012  7:25:20.797, peer=41909,
>>>>> tc=4, mintc=3, offset=-0.034, frequency=-25.214, sys_jitter=0.002,
>>>>> clk_jitter=0.002, clk_wander=0.001
>>>>>  Here are my website graphs/stats I've been keeping since day 1.
>>>>> NTP Clock Offset:http://godzilla.empire.org:9999/
>>>>> NTP Offset from UTC:http://godzilla.empire.org:9999/godzilla_ntp-b.html
>>>> Could you also post output from ntpq -p
>>>> I don't have a pc with recent FreeBSD but the desktop
>>>> I updated to NetBSD-6 only 2 hours ago gives:
>>>> remote                refid        st t poll reach delay offset jitter
>>>> +ntp1.lordynet.org    81.187.61.74  2 u  512   377 0.450 -4.961  3.024
>>>> *ntp0.lordynet.org.uk .MSFa.        1 u  512   377 0.642 -0.828  4.785
>>>> +<local pc>           .PPSb.        1 u  512   377 1.572 -1.935  3.187
>>>> -<local pc2>          81.187.61.74  2 u  512   377 1.553 -6.075  3.892
>>>> Does the Sure have a PPS output you can use?
>>>> <Local pc> is using a Sure with PPS
>>>> # ntpq -c rv -p me6000
>>>> associd=0 status=0119 leap_none, sync_pps, 1 event, leap_armed,
>>>> version="ntpd 4.2.6p5....",
>>>> processor="i386", system="NetBSD/5.1_STABLE",
>>>> .....
>>>> offset=-0.001 sys_jitter=0.004
>>>> David
>>> Here is my ntpq -p  output:
>>> [a... at godzilla.empire.org(tcsh):6] ntpq -p
>>>      remote           refid      st t when poll reach   delay
>>> offset  jitter
>>> ==============================================================================
>>> -ntp.alaska.edu  .GPS.            1 u  133  128  377  120.428
>>> -2.464   0.371
>>> +utcnist2.colora .ACTS.           1 u   53  128  377   66.362
>>> -4.215   0.429
>>> -time-a.nist.gov .ACTS.           1 u  670  128  240   16.473
>>> 2.627  17.066
>>> +tick.usask.ca   .GPS.            1 u  110  128  377  104.848
>>> -3.473   1.482
>>> -cronos.cenam.mx .GPS.            1 u   49  128  377  100.163
>>> 10.784  27.096
>>> oPPS(0)          .PPS.            0 l    6   16  377    0.000
>>> -0.018   0.002
>>> *GPS_NMEA(0)     .GPSb.           0 l    9   16  377    0.000
>>> -36.164  18.050
>>> [a... at godzilla.empire.org(tcsh):7]
>> Sorry I misread your message and had in my mind that you
>> were getting msec offsets rather than usec. I canceled my
>> reply after posting.
>>
>> The offsets still look to be high for what can be achieved
>> from pps but are not reflected in the jitter.
>>
>> David
> 
> 
> 
>  Does this mean there is something I need to tweek to get
> my offsets lower? Could the delays from the remote NTP
> servers be my issue?

I don't know if that's the case. I setup my two servers
to use the nearest ntp servers that didn't share the same
sources. There are tools to assist in the ntp distribution
or you can select from the list of public servers at
ntp.org. The stratum is usually of no importance. I had
several stratum3 servers in my initial selection but the
same servers are now stratum2 or stratum1. By nearest, I
mean those with shortest delay.

I'd remove the sources with highest delay, maybe just by
marking as noselect.

My own server with gps/pps source gives a couple of blips
each morning due to load from cron jobs. The other pcs
show variations from load and from temperature.

http://www.lordynet.org.uk/mrtg/stats/ntp/


David



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