[Xymon] top ten list of servers wrt cpu load

[Steve Holmes]

On Mon, Mar 18, 2013 at 6:27 PM, Jeremy Laidman <jlaidman at rebel-it.com.au>wrote:

> On 19 March 2013 06:55, Steve Holmes <sholmes42 at mac.com> wrote:
>
>> So, I'm looking it writing a script to mine the rrd or history data from
>> the Xymon server to produce the list he wants. He is also interested in the
>> top disk I/O numbers, too, but I'm focusing on load average for now.
>>
>
> Sounds useful.  I've not seen anything that does this already.
>
>
>> close so I was looking at rrdtool fetch. However, this is cumbersome and,
>> frankly I'm not understanding the data I'm getting back (for example
>> 1.22749483e+03 seems to be 12.27... when I compare it to the graphs, so the
>> e+03 seems to really mean *10^1, right?)
>>
>
> Nope, 1.227+03 means 1227.  However, sometimes there is an adjustment
> applied, that's not always obvious.  For example, my understanding is that
> the load average (in la.rrd) is recorded after multiplying by 100, which is
> an artefact of the BigBrother legacy, because floating-point comparisons
> were difficult to implement in a generic shell script that had to run on
> any *nix platform.  The BigBrother data collector would chop everything
> after two decimal places, then strip the dot out, thus providing a load
> average factored up by 100.  You can tell this is what's happening in Xymon
> by looking at the [la] entry in graphs.cfg, or to save you looking it up:
>
>         DEF:avg=la.rrd:la:AVERAGE
>         CDEF:la=avg,100,/
>
> So the graphs.cfg entry scales it back down before graphing.
>
> Similar adjustments are made for things like interface load and TCP/IP
> stats, where bytes-per-second are converted to bits-per-second.  Again, the
> graphs.cfg file often gives you a clue as to what's going on.
>
> J
>
>
Attached is the perl script I came up with. It serves my purpose and might
be useful to someone. $fudge will have to be expanded for other measures. I
may do that if someone here at Purdue requires it. Otherwise have at it.

Steve Holmes
Purdue
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