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> - for ceilometer-collector, so it inside the collector: it will
>   always know what the last value is, since it's stored in the
>   database. So it just has to fetch the last stored value from
>   the db if it doesn't know it, compute the delta, and stores it.

Yep, that's pretty much what I meant by:

"However doing the adjustment within the metering store would always
be possible (either by storing a running offset as well as the reported
values, or switching to a delta-based measurement)"


> My main concerns in this, is that it'll be stored as a
> delta. We'll have to be clear that polling this kind of things,
> like delta in general actually, can't be done multiple times in
> parrallel. Something that is easily done -- though maybe not
> generally wanted -- with cumulative counters.

Hmmm, are you thinking of the case where there are multiple
ceilo agents running the same compute host, but duplicating
the pollsters they've loaded?

Seems more likely to me that multiple ceilo compute agents
would take a disjoint subset of the pollsters each, rather
than duplicating.

Or, by "polling ... done multiple times in parrallel" do you
mean querying the ceilo API in parallel?

Cheers,
Eoghan