[rrd-users] Aggregate/combine several RRDs

Raimund Berger raimund.berger at gmail.com
Sat Jun 21 04:44:49 CEST 2008

Alex van den Bogaerdt <alex at ergens.op.het.net> writes:

> On Fri, Jun 20, 2008 at 11:37:24PM +0200, Raimund Berger wrote:
>> > Have you looked at rrdtool xport ?
>> That one looks better, thanks a lot.
>> Incidentally, and as I admittedly didn't look at those xml outputs
>> very closely yet, do you know if xport does write dump format, so it's
>> output can directly be fed into restore again?
> No, I don't know. But if I may guess: no, I don't think it can.

That was my initial guess when I said "not directly supported". So to
kind of finally answer OP's question, the kind of data aggregation he
asked for is apparently best supported only when graphing.

If he still wants to sample the aggregated data into an intermediate
RRD to save cpu cycles, he has to do xports, because only those
provide the defs and cdefs he presumably wants to perform, and then
parse the xml output into corresponding update calls himself.

If he does an attempt on this, as already said, the intermediate data
type should likely be gauge, to avoid distortion due to rrdtool rate
calculations, and there should best be no consolidation function
performed for the same reason, i.e. steps=1 in the RRA definition.

That's at least what I understand at this point.


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