On Thu, Jul 6, 2017 at 9:38 AM, Arik Hadas <ahadas@redhat.com> wrote:


On Wed, Jul 5, 2017 at 9:36 PM, Shirly Radco <sradco@redhat.com> wrote:


--

SHIRLY RADCO

BI SOFTWARE ENGINEER,

Red Hat Israel

sradco@redhat.com   


On Wed, Jul 5, 2017 at 6:35 PM, Arik Hadas <ahadas@redhat.com> wrote:


On Wed, Jul 5, 2017 at 5:57 PM, Roy Golan <rgolan@redhat.com> 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.
 


_______________________________________________
Devel mailing list
Devel@ovirt.org
http://lists.ovirt.org/mailman/listinfo/devel


_______________________________________________
Devel mailing list
Devel@ovirt.org
http://lists.ovirt.org/mailman/listinfo/devel



_______________________________________________
Devel mailing list
Devel@ovirt.org
http://lists.ovirt.org/mailman/listinfo/devel