Strange load average with Nagios 3

[Yann Jouanin]

>> 
>> Has anyone the same observation ?

>I've never seen anything like it before. Does the 4-hour interval coincide
>with your check-interval? Does it align with some performance-data
processing?

No, we process performance data every 15 seconds (and even when stopping
processing pattern still reproduced).
Our check-interval are 1min and 5 min, it doesn't seem to be correlated with
the 4hours slot.

>> Can something in Nagios behavior explain
>> this load ?

>Not really, no. I suppose a database logging application could display a
load
>pattern such as this if it manages its tables really poorly and then
vacuums
>them at the peak of the load, but since you mentioned nothing about
NDOUtils
>or anything similar I'll just assume you have no such things installed.


There is no mysql nor NDOUtils running on these servers.
Only Nagios and PNP (NPCD + BULK)

>> Our servers are running different Linux distributions and we spot out the
>> fact that the pattern is certainly due to Nagios.
>> 

>How did you ascertain this? Sorry for being skeptical, but I've seen
>"Oh I'm really, really sure" followed by "oops turned out I was wrong"
>too many times to trust other's eyes ;-)

I can understand your skepticism, let's say we strongly guess (instead of
certainly!) this is due to nagios: 
	-  stopping NPCD doesn't change the pattern. 
	-  we check cronjob, nothing was running with a 4 hour periodicity
	-  the different servers don't run the same services (E.G : some
have backup with bacula, some not)
	-  We can unfortunately not stop the nagios process (because it's
production!) but, the amplitude of lobes seems to be quite correlated with
the number of services.



Yann



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