[rrd-users] Adding two VDEF values together

[Chris Mason]

Hi,

I was trying to do something which I thought was fairly simple, but I
keep on getting the following error:

"ERROR: rpn expressions without DEF or CDEF variables are not supported"

In the most simplest form, I am trying to do the following:

DEF:A=<rrdfile>:A:AVERAGE
DEF:B=<rrdfile>:B:AVERAGE

VDEF:TA=A,TOTAL
VDEF:TB=B,TOTAL

CDEF:TAB=TA,TB,ADDNAN

So, a VDEF is a set of data and a CDEF is a single value, but a TOTAL
will be a single value?

I am trying to take two totals and add them together - seems fairly
common to want to do this?

I am using RRDTOOL 1.4.7 - is there an easy way to achieve this, can I
put TA and TB in a CDEF before using ADDNAN?

Thanks as always,
Chris