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

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'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