[Xymon] How is clock graph in "trends" column generated

[Junaid Shahid]

Thank you Jeremy for your suggestion!

I have run this command on the client, but I don't know what conclusions
can I draw from it. Here is the outptu, (after being dropped to xymoncmd):

==================================================================
# time /usr/libexec/xymon-client/xymon 10.12.12.44 "client/timetest
zm1.i2cinc.com.Linux"
ignore mail.info
file:/etc/passwd:md5
file:/etc/shadow:md5
log:/var/adm/messages:10240
0.00user 0.00system 0:00.00elapsed 33%CPU (0avgtext+0avgdata
680maxresident)k
0inputs+0outputs (0major+200minor)pagefaults 0swaps
==================================================================

BTW I do see clock offsets as big as 45 seconds reported on the "CPU" page
for this client.

Thanks.

On Wed, Jun 29, 2016 at 4:46 AM, Jeremy Laidman <jlaidman at rebel-it.com.au>
wrote:

> On Tue, 28 Jun 2016, 23:27 Junaid Shahid <shahid.junaid at gmail.com> wrote:
>
>> Thanks JC!
>>
>> Now that makes it very clear how CPU stats contain server's timestamp
>> (and why).
>>
>> I have checked we are running version 4.3.21.
>>
>> Now lets look at the reasons of skew:
>> a) your xymon server itself is wrong
>> Our server's time is correct (as I have manually checked it multiple
>> times manually and also with "ntpstats"). Plus, we have some 300+ clients
>> under Xymon monitoring, and none of them exhibit any time skew in their
>> CLOCK Offset trends
>>
>> b) you have a xymonproxy in the middle and messages are delayed getting
>> to xymond
>> We don't use any xymon proxy
>>
>> c) your xymond_client process is backlogged with [client] messages
>> This also can't be the reason because all other clients don't exhibit any
>> noticeable skew in their respective Clock Offset trends
>>
>> d) your xymon server is overloaded and has a long period between transmission
>> and TCP processing by xymond
>> This also must not be the case as no other client show any noticeable
>> Clock Offset trend.
>>
>>
>> In our case there is one specific server (out of 300+) that has a
>> clock offset trend that alternates b/w 2-15 secs (like a sinusoidal wave).
>> This machine's time is in perfect sync with our NTP server though (no
>> clock drift exists actually). This machine has a little complicated network
>> topology though (behind various layers such as firewalls, load balancers
>> etc). My only guess now is that this is because of its weird network
>> location, what do you think JC?
>>
>
> I tend to agree. If it takes a few seconds to make a TCP connection to the
> xymon server and transmit the client message, you will see such a delay.
>
> Try manually sending a client message and see how long it takes. Something
> like:
>
> $ time $XYMON $XYMSRV "client/timetest $MACHINE.$SERVEROSTYPE"
>
> (run within a xymoncmd shell on the client)
>
> J
>
>


-- 
Regards,
Junaid Shahid,
TODO:______
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