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On Tue, Sep 01 2015, gord chung wrote:

> but if it's not actually cumulative in Ceilometer (pre-storage), should we
> really be tagging it as such?

We only have 3 meters type, and the cumulative definition I wrote
somewhere back in 2012 states that it can reset to 0. Sorry. :-)

> so i was thinking rather than modify the existing meter, we build a new
> cpu.delta meter, which is gives the delta. it seems like giving a delta meter
> would make the behaviour more consistent.

…with data loss if you restart the polling agent and it then ignores the
previous value of the meter.

Except if you connect the polling system to the previous state of the
meter, which requires to either:
1. Connect the polling system to the storage system
2. Store locally the latest value you fetched

Option 1 sounds crazy, option 2 sounds less crazy, but still hackish.

Whereas having a system that can compute the delta afterward with all
the value at its reach sounds way better – that's why I'm in favor of
doing that in the storage system (e.g. Gnocchi).

-- 
Julien Danjou
;; Free Software hacker
;; http://julien.danjou.info
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