[smokeping-users] Problems with detail graph scaling

David Tomic young_einstein at internode.on.net
Wed May 21 06:37:54 CEST 2008

Dan Hamilton wrote:
> The other issue is with the scaling on some of the detail graphs.  It 
> appears that the top of the smoke is being chopped off sometimes.  For 
> instance, this page:
> http://wdf1.waterloodatafortress.ca/cgi-bin/smokeping.cgi?target=icmp.icmpinternet.icmpinternet1
> The 3-hour graph only shows smoke up to 14ms, but in reality I know 
> there should be peaks above 100ms.  The 30-hour graph is more realistic, 
> taking into account the time compression.
> I'm running Smokeping 2.3.6 and rrdtool 1.2.27.

That's because of the unison_tolerance setting in your smokeping


     if a graph is more than this factor of the median 'max' it drops
out of the unison scaling algorithm. A factor of two would mean that any
graph with a max either less than half or more than twice the median
'max' will be dropped from unison scaling

The 30-hour graph is only showing 'properly', because the spike in your
median rtt means that the rest of the smoke doesn't need to be chopped off.

Once you zoom in on the 30-hour graph, so that you remove that large
spike, then you'll see that it goes back to cutting off the smoke again.

If you want to have it so that all the smoke is visible, then you just
need to set a [much] higher unison_tolerance setting in your smokeping
configuration file.

--David Tomic

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