Combining two interfaces into one graph item

[jlscott]

I've looked through all the posts on CDEFS and combo graphs but none of the information has helped and the manual is sparse.

I am trying to make a graph which uses two ethernet interfaces as its datasources, combines their values then outputs this to a single inbound area and single outbound line on a graph.

Could someone post up or point me to information which leads you step by step through doing this? My efforts so far making graph templates have failed miserably.

Thank you

[Paul Thexton]

I did this with the following template .... What you need to do is create a copy of an interface traffic graph, define secondary input/output data sources... and then use a cdef function to combine the input & output sums to draw the graph properly.

Unfortunately the only way can do this is if you have the original primary/secondary interface data still being drawn on the graph, otherwise the source rrd files aren't specified to rrdtool and you have no data to work with... I achieved this by setting a nondistinct colour for the separate interfaces and have them drawn as LINEs (the combined "area" part of the graph seems to hide it well).

To make it easier i've attached my template for you.

[jlscott]

Excellent! Thank you so much. I've imported your template and got this working. This should be stickied!

[Paul Thexton]

Excellent!

Happy to help

[it]

how you can do the same work for multiple data sources.
variable number of datasources??

any idea??

thx