Calculations of RRD data

[Stephen H. Dawson]

Yes, we use DRRAW as well.  However, running those cal's, and then graphing
within Nagios or DRRAW or pnp4nagios would be nice.

I guess it is an export from RRD, do the calc's, and review outside of
Nagios/DRRAW/pnp4nagios kind of thing?


Thanks,
SHD 

-----Original Message-----
From: averyjim at gmail.com [mailto:averyjim at gmail.com] On Behalf Of Jim Avery
Sent: Monday, August 09, 2010 11:35 E/T
To: service at shdawson.com; Nagios Users List
Subject: Re: [Nagios-users] Calculations of RRD data

On 8 August 2010 19:47, Stephen H. Dawson <service at shdawson.com> wrote:
> Hi,
>
>
> Not sure if this is the correct place to ask this question, but 
> starting here.
>
> We use Nagios for lots of monitoring, and store that data in the RRD 
> database.  We graph that data.  Life is good.  We have some odd 
> thoughts about "what if" scenarios, where we need to further review 
> the data in the RRD database.  Simple arithmetic calculations of 
> minus, division, and then some averaging of some of those minus and
division outputs.
>
> We really do not want to put the monitored data into a SQL database.  
> How
> (hopefully) does one do arithmetic calculations of data in an RRD 
> database, please?


I find DRRAW really useful for that sort of thing.  As Marc said, you can
use rrdgraph to do these things - DRRAW just makes it easier.

For a version which was developed to add functionality specific to
PNP4Nagios, see:
http://www.semintelligent.com/blog/articles/39/pnp-aware-version-of-drraw-re
leased

I'm not sure if this was ever rolled in to the main DRRAW release which is
at http://web.taranis.org/drraw/


You can also use the rrdtool xport utility to export information from an rrd
to a .xml, doing some calc on it in the process, for example here's one
where I get data from three different rrd files:



#!/bin/sh

rrdtool xport  \
  --start "end -14 day" \
  --end "07/12/2010 00:00" \
  --step  3600 \
  --enumds \
  DEF:a=/usr/local/nagios/share/perfdata//chp-p15/Load.rrd:1:AVERAGE \
  DEF:e=/usr/local/nagios/share/perfdata//chp-p16/Load.rrd:1:AVERAGE \
 
DEF:b=/usr/local/nagios/share/perfdata//chp-p15/BIS_count_tBPInstances.rrd:1
:MIN
\
 
DEF:c=/usr/local/nagios/share/perfdata//chp-p15/BIS_count_tBPInstances.rrd:1
:MAX
\
  CDEF:d=c,b,- \
  XPORT:a:"Load Average App" \
  XPORT:e:"Load Average DB" \
  XPORT:d:"tBPInstances Delta" \
  XPORT:b:"tBPInstances Min" \
  XPORT:c:"tBPInstances Max" > 14days-to-20100623.xml


The xml file can then be easily imported in to Microsoft Excel so you can do
futher maths on it if you wish.

See:

http://oss.oetiker.ch/rrdtool/doc/rrdxport.en.html


Another neat thing you can do is use rrdcgi to publish graphs on the web.
See:

http://oss.oetiker.ch/rrdtool/doc/rrdcgi.en.html

I found the learning curve for all this lot fairly steep, but using drraw
helps (as it can show you what rrd commands it is building) and the rewards
are great.

hth,

Jim


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