[ntp:questions] two machines syncing to the same master - hardware issues?
matthew.garman at gmail.com
matthew.garman at gmail.com
Fri May 31 13:36:39 UTC 2013
On Thursday, May 30, 2013 5:41:46 PM UTC-5, unruh wrote:
> > My two machines are somewhat different: "oldbox" is running NTP 4.2.2 as ships with RedHat 5.7; "newbox" is running NTP 4.2.4 as ships with RedHat 6.3.
>
> Why?
Because oldbox has a lot of other custom functions that haven't been validated against the newer OS. newbox does only NTP, so we're not stuck with the older version.
> Plots would be good.
> Plot the offset vs time from the peerstats file. You might discover that
> your understanding is wrong.
Currently I'm not generating a peerstats file, but will change that after business hours this evening.
> > I'm measuring the offset via "ntpdate -q <peer ntp server>"
>
> Very silly way of doing it, esp since your machine measures the offset
> every few minutes already.
Where can I access this information? I assume from the peerstats file? Or is there another mechanism for querying this pre-existing data?
> > Is it possible there is a hardware problem with newbox? I don't really understand NTP well enough to know where to start looking.
>
> It is possible. What operating system is on newbox? And it could be that
> something on the box is resetting the clock behind ntpd's back.
newbox is running Redhat (CentOS actually) 6.3.
How can I determine if something else is messing with the clock?
> You can expect offsets of the order of 10-20microseconds IF the ntp
> servers get their time from gps. If not, the servers themselves can be
> woggling all over the place.
Is there any way to determine if the ntp servers are using GPS or not?
Thanks again.
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