[hobbit] Mysterious Sawtooth Graphs

[Alan Sparks]

thorsten.erdmann at daimler.com wrote:
>
> Hi
>
> I use Hobbit to monitor about 700 systems. I get some mysterious
> looking graphs with the CONN test and also the bbgen test itself.
> It looks like two overlayed sawtooth curves. Any idea why the graphs
> look so weird? I cannot believe these are the real response times.
>
> Here are two demo pics:
>
> http://www.trektech.de/test/hobbitgraph_conn.png
> http://www.trektech.de/test/hobbitgraph_bbtest.png
>
> BTW.: is there a way to speed up the connect test. It needs about
> 35sec which is not critical but not very fast.

I've seen them too.  Even on HTTP test graphs.  And also not entirely
sure why.

As far as the ping bounces around 20-40ms are concerned, this is a
problem with hobbitping, and its polling algorithm.  If you want the
timing correct, I highly suggest you switch to fping.  Install fping and
change the FPING setting in hobbitserver.cfg:
FPING="/usr/sbin/fping"

Note: I've used the following on mine with good luck, for several
thousand machines:
FPING="/usr/sbin/fping -i10 -t1500 -r2"

Note you must make sure the xymon or hobbit user has rights to run
fping, either by a sudo arrangement or by setting up a setuid capability
such as:
chmod g+x /usr/sbin/fping
chgrp xymon /usr/sbin/fping
chmod u+s /usr/sbin/fping

Not sure about your statement regarding connect tests running 35
seconds. You mean the ping or tcp test times listed in the bbtest info
page? Or the test setup or DNS resolve times? For 700 hosts, 35 seconds
isn't too bad, I've seen 4000 hosts or so run in maybe 110-120 seconds.
-Alan