Re: [ovirt-devel] Chaning the statistics monitoring interval to 30s

On Thu, Jul 6, 2017 at 12:19 PM, Roy Golan <rgolan(a)redhat.com&gt; wrote: > > > On Thu, Jul 6, 2017 at 12:18 PM Roy Golan <rgolan(a)redhat.com&gt; wrote: > >> Action items: >> - Demonstrate the effect of the reduction of stats collection on the >> system - WIP >> - Code changes: >> - config item change: NumberVmRefreshesBeforeSave from 5 to 10 >> - make the 'poll' vms job to fire at NumberVmRefreshesBeforeSave / 2 >> (or just make the code to support explicit time interval) >> - VDSM should get a config set with the sampling inteval - to support >> back-compat >> >> - Chages to DWH sampling and ManageIQ? > I think manageIQ can cope with either 60 seconds or 20 seconds intervals (after a change we've made when we moved to 20 seconds). Put an action item indeed to check that with us if we'll decide to do so.

> >> >> >> On Thu, Jul 6, 2017 at 11:00 AM Yaniv Kaul <ykaul(a)redhat.com&gt; wrote: >> >>> On Thu, Jul 6, 2017 at 10:04 AM, Oved Ourfali <oourfali(a)redhat.com&gt; >>> wrote: >>> >>>> >>>> >>>> On Thu, Jul 6, 2017 at 9:38 AM, Arik Hadas <ahadas(a)redhat.com&gt; wrote: >>>> >>>>> >>>>> >>>>> On Wed, Jul 5, 2017 at 9:36 PM, Shirly Radco <sradco(a)redhat.com&gt; >>>>> wrote: >>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> >>>>>> SHIRLY RADCO >>>>>> >>>>>> BI SOFTWARE ENGINEER, >>>>>> >>>>>> Red Hat Israel <https://www.redhat.com/> >>>>>> >>>>>> sradco(a)redhat.com >>>>>> <https://red.ht/sig> >>>>>> <https://redhat.com/summit> >>>>>> >>>>>> >>>>>> On Wed, Jul 5, 2017 at 6:35 PM, Arik Hadas <ahadas(a)redhat.com&gt; >>>>>> wrote: >>>>>> >>>>>>> >>>>>>> >>>>>>> On Wed, Jul 5, 2017 at 5:57 PM, Roy Golan <rgolan(a)redhat.com&gt; >>>>>>> wrote: >>>>>>> >>>>>>>> Hi all, >>>>>>>> >>>>>>>> I would like to get feedback on $subject and see if I'm missing >>>>>>>> something. The impact of this is simply less resource consumption and by >>>>>>>> that we can support even greater number of hosts [1] and vms in the system. >>>>>>>> >>>>>>> >>>>>>>> If you think more relaxed statistics collection will affect a core >>>>>>>> flow let me know - as far as I see I didn't spot anything critical. >>>>>>>> >>>>>>> >>>>>>>> The overhead of a cycle per host something like that: 2 roundtrips >>>>>>>> per host in a cycle, (vm + host stats) and tons of memory allocation for >>>>>>>> char[] -> json-> maps of maps -> VM/Vds statistics -> Maps -> serialiazing >>>>>>>> to DB. >>>>>>>> >>>>>>>> To minimize the effect of this change we can leave a call to >>>>>>>> 'list' verb to at least detect vms existence in the same rate as today. >>>>>>>> >>>>>>> >>>>>>> +1 >>>>>>> >>>>>>> >>>>>>>> >>>>>>>> Pros >>>>>>>> - Engine has rore resources to support more hosts/vms/other >>>>>>>> activities of the engine >>>>>>>> - Vdsm will have more resources as well (need to tweak vdsm to >>>>>>>> collect in the same >>>>>>>> frequency) >>>>>>>> - less DB writes and reads, approx half of what the system will do >>>>>>>> in the in its lifefpan (cause this is what is mainly does all the time) >>>>>>>> >>>>>>>> Cons >>>>>>>> - DWH/Dashboard will have less entries, I'm not sure what is >>>>>>>> graphical affect given our hourly resolution (cmiiw here) >>>>>>>> >>>>>>> >>>>>>> What's the frequency of the queries done by DWH/Dashboard? Do they >>>>>>> count on the _update_date column of the queried data? >>>>>>> >>>>>> >>>>>> Current frequency is 20 seconds. >>>>>> The configurations are queried based on the _update_date, but >>>>>> statistics are queried every interval. >>>>>> >>>>>> The affect will be less accuracy in the hourly calculations. >>>>>> >>>>> >>>>> Ack. So if the proposed change is done, it would probably make sense >>>>> to increase the inverval of those queries to be higher than 30 sec, or at >>>>> least taking into consideration the _update_date of vm_statistics as well. >>>>> >>>>> >>>> >>>> Note that it will cause issues with cloudforms to change those queries >>>> to 30 seconds, so I guess we'll still query it every 20 seconds (although >>>> the data won't change in some of those queries). >>>> >>> >>> I thought it was configurable in ManageIQ how often to query, but in >>> any case even if we query every 20 seconds, we'll get updated VM stats, >>> which is fine, and not as updated hosts stats, which is fine as well, from >>> my perspective. >>> Y. >>> >>> >>>> >>>> >>>> >>>>>> >>>>>>> I'm asking because if they query the database every minute and say >>>>>>> "the time now is 10:30 and the queried data is ..." then there should not >>>>>>> be less entries. >>>>>>> >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1430876 >>>>>>>> >>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> Devel mailing list >>>>>>>> Devel(a)ovirt.org >>>>>>>> http://lists.ovirt.org/mailman/listinfo/devel >>>>>>>> >>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> Devel mailing list >>>>>>> Devel(a)ovirt.org >>>>>>> http://lists.ovirt.org/mailman/listinfo/devel >>>>>>> >>>>>> >>>>>> >>>>> >>>>> _______________________________________________ >>>>> Devel mailing list >>>>> Devel(a)ovirt.org >>>>> http://lists.ovirt.org/mailman/listinfo/devel >>>>> >>>> >>>> >>>> _______________________________________________ >>>> Devel mailing list >>>> Devel(a)ovirt.org >>>> http://lists.ovirt.org/mailman/listinfo/devel >>>> >>> _______________________________________________ >>> Devel mailing list >>> Devel(a)ovirt.org >>> http://lists.ovirt.org/mailman/listinfo/devel >> >> _______________________________________________ Devel mailing list Devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/devel