[rrd-users] Aggregate/combine several RRDs

[Raimund Berger]

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

> On Fri, Jun 20, 2008 at 09:41:18AM +0200, Raimund Berger wrote:
>
>> The question is still of technical interest though, whether to create
>> intermediate RRDs for this kind of usage. This basically boils down to
>> the computing versus storage cost question I guess, plus the issue of
>> creating an additional point of error/failure.
>
> Creating another RRDfile isn't hard to do.  Filling it with numbers
> isn't hard either.  The biggest challenge is to get your minimum and
> maximum rates correct.
>
> When reading a previous RRD (e.g. with fetch) you will get rates.
> This probably means your new RRD should have data source type GAUGE.

Right. The assumption would likely be to create an intermediate
RRD/RRA with same feed interval as the source(s) but basically no
consolidation on whatever you do with that data, i.e. primarily
graphing I guess. Anything else would lead into computational and
interpretational fine print, as you further line out.

And agreed, fetch and update via a script should not be too hard to
accomplish.

I have to take a rain check on the algorithmic discussion
though. Consecutive appliance of a min, max, average, last function
set in the various possible permutations while retaining some distinct
meaning and purpose is beyond my scope right now.

Thanks, R.