Custom graphing (with ncv) is really a two step process. The first and most important is collecting the data into an rrd, which is simple and done by adding your COLUMNNAME=ncv to TEST2RRD and correctly passing data back to hobbit:) I used "rrdtool dump foo.rrd > tmp.xml" to verify that it was actually collecting some data.
I would venture to guess that as long as your test/column names stay the same, there will be no problems in switching from --extra-tests to ncv.
The second step, of course, is actually graphing it using data from the rrd. I found this to be the most difficult step, if only because I skim documentation - I don't read unless I'm desperate. Again, I'm going out on a limb to say as long as your datasources/testnames/Y values are all the same, your graph configuration should work post-ncv conversion.
Good luck
Thanks.
Dan
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