NTP monitoring

[Dalin Bruns]

Is it common practice to monitor NTP status? If so, from ntpq -p, what is the most tell-tale indicator that things are good/bad, i.e. is there one parameter that I can watch such that when that parameter reaches a specific threshold, user intervention is required?

Thanks in advance,

Dalin

[Pete Randall]

Dalin,

NTP should be pretty much self healing. You might want to review syslog entries just to assure yourself that all is well:

"grep -i ntp /var/adm/syslog/syslog.log"


Pete

[Uday_S_Ankolekar]

NTP is pretty simple and reliable.
If you have any doubts about your setup use this command to monitor connection
ntpq -p
The "reach" value will move towards 377 if the connection is reliable.
Also check for the /var/adm/syslog/syslog.log file for ntp logs.

and xntpd is the daemon should be always running

-Uday

[Robert-Jan Goossens]

Hi,

Look for entry's in your syslog, like "Lost connection to stratum" if you do not find them in your syslog you are pretty save.

Hope it helps,

Robert-Jan.

[Dalin Bruns]

I agree that NTP takes care of itself running on its own, but recently our time source, some type of satellite link device began to fail, and we didn't realize it until time between several of our servers had begun to drift enough to cause us some database issues. In hindsight, as the device failed, it was over a week or so before we were awakened to this issue by the database and I was hoping to head this sort of thing off at the pass.

Dalin

[Robert-Jan Goossens]

Hi Dalin,

How many servers are connected to your ntp gps device ?

Robert-Jan.

[Dalin Bruns]

Interestingly, we routinely see synchronisation lost messages in the syslogs of our machines, following by a resync minutes later. I was, more specifically, wondering, if I monitor the dispersion value from ntpq -p, whether that value would be a good indicator of ntp status.

Dalin

[Sergejs Svitnevs]

Check out the following link:

http://nic-ks.greatplains.net/ntp/debug.htm


Regards,
Sergejs

[Robert-Jan Goossens]

Dalin,


What do the "ntpq -p" output fields mean?
DocId: KBRC00001347 Updated: 2/14/00 9:51:55 AM
PROBLEM
The details of the "ntpq -p" output fields

http://www4.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000063235965

Robert-Jan.

[Pete Randall]

Dalin,

We see synch lost and resynch messages as well. I suspect that this is completely normal. For ongoing monitoring, I would suggest a cron job that greps syslog for ntp messages once a day and emails the output to you. You could get fancy and check for a synch lost without a corresponding resynch, but a little manual review would also work without too much effort.


Pete