[Nagios-devel] Feedback on Nagios

Marcus Vogt mgvogt at bigpond.com.au
Sat Dec 13 15:48:01 UTC 2003


Hi,


Jason Martin wrote:

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>>Now this isn't a major problem for us - I wrote discovery scripts in 
>>perl that given a list of
>>    
>>
>Would you be interested in sharing this script?  
>
I am happy to, but I have to get approval from work for this.  I'll talk 
to them during the
week.  Please  be aware though that even though they work they are still 
what I would
call prototypes.

>
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>>Currently with the first sweep of discovery (excluding networking type 
>>queries) we ended up with around
>>300 hosts and 1500 services with checking of services every 5 minutes. 
>> This absolutely hammered CPU of the
>>box it was on (Sun E250 Dual CPU and 2Gb Memory).  This was okay, we 
>>used the embedded perl option
>>and this got us to just under 100% utilisation.  Yes this is an issue 
>>with the plugins and I'll discuss this later.
>>    
>>
>Perl really isn't a great idea for plugins that get executed frequently; 
>it's just too large of a process.  I've head that using perlcc improves 
>matters as well.
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Perl is expensive to start up, but I find it a darn good prototyping 
tool :)  I was hoping the
embedded perl would help matters (which it does a fair bit) but I have 
not tried perlcc for
the plugins.  My intention is to take the lessons from the perl 
prototypes and implement
in C as I discussed at the bottom of the original email.

>  
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>>tool for further processing.
>>such as counters.  Admittedly we run this at maximum nice levels to 
>>ensure it does not impact primary
>>data collection work.
>>    
>>
>You might consider splitting the graphing mechanism off to a different 
>machine to lighten the load on the collector.
>  
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Unfortunately, this is not practical in my environment at this time.

>  
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>>** Nagios does not natively deal with counters - not really a Nagios 
>>problem, just an observation. i.e. write your
>>    
>>
>I believe one of the selling points of Nagios is that it is completely 
>plugin agnostic -- it cares not what you are monitoring. Going down the 
>path of making it understand what certain plugins are doing would probably 
>greatly increase complexity and reduce stability.
>  
>
I agree that plugins are one of Nagios's main selling points.  I like 
that I am not limited to
provided queried as I am with NNM.  I have already created plugins that 
use RRD tool
to handle counters.  It just would have been "nice" to have that feature 
in Nagios.

>  
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>>This is a real concern as NNM can do this without even breaking a sweat 
>>- admittedly it does not have the dependency type
>>information included.
>>    
>>
>I think a more accurate comparison would be if you left out the dependency 
>information when taking the timings.
>  
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True.   It will be dificult (getting the time approved at work) to 
provide a "fair" comparison
between the two.

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>>I have seen patches to improve performance on this (have not yet 
>>implemented/tested) and I think this is improved on the next
>>version.
>>    
>>
>The docs indicate that Nagios will create a 'compiled' config file for the 
>CGI's to read that will be less expensive.
>  
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That sounds like a real improvement.  Given that this project lives or 
dies by the perception
I did not consider it wise to go with a development version at this 
stage.  I'll trial it when
it gets officially released.

>  
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>>** I am not sure that active checks scale at all well under Nagios.
>>    
>>
>You can also use distributed monitoring if you've maxed out your active
>check capacity on a given machine.
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Good point.  I have not played with this yet - though it is scheduled 
for other reasons.  I'll
let people know how it goes when I get there.

>- -Jason Martin
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Cheers,


Marcus.





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