On Tue, May 29, 2012 at 1:10 PM, Matt Joyce <matt.jo...@cloudscaling.com>wrote:
> Do we want a history of deltas or just last delta and leave the history to > UI implementers? The collector should record everything and we should make the query API work so the caller can get what they want out of the datastore. > > > On Tue, May 29, 2012 at 9:30 AM, Loic Dachary <l...@enovance.com> wrote: > >> On 05/29/2012 05:42 PM, Doug Hellmann wrote: >> > IIRC, the meters discussed in the wiki [1] are supposed to show "delta" >> values (usage since the last time an event was generated), although the >> "Alternate Gauge Design" section discusses cumulative meters instead. The >> libvirt pollsters we have now produce cumulative data, and it might be >> complicated and error-prone to change them to compute the deltas internally >> before generating events. On the other hand, some of the other counters may >> be more complicated to generate as cumulative values. >> > >> > Rather than taking an either/or approach, I propose we document for >> each counter whether it uses the delta or cumulative approach. The API >> server can ask the meter plugin for that piece of information when >> calculating the aggregate value so that the caller does not have to keep >> track of the rules for each meter. >> > >> I tend to prefer using a gauge and I agree that documenting what was >> preferred (gauge or delta) for a given meter / counter is enough. >> >> My 2ct ;-) >> >> -- >> Loïc Dachary Chief Research Officer >> // eNovance labs http://labs.enovance.com >> // ✉ l...@enovance.com ☎ +33 1 49 70 99 82 >> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~openstack >> Post to : openstack@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~openstack >> More help : https://help.launchpad.net/ListHelp >> > > > _______________________________________________ > Mailing list: https://launchpad.net/~openstack > Post to : openstack@lists.launchpad.net > Unsubscribe : https://launchpad.net/~openstack > More help : https://help.launchpad.net/ListHelp > >
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