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

[Yaniv Kaul]

On Thu, Jul 6, 2017 at 10:04 AM, Oved Ourfali <oourfali at redhat.com> wrote:

>
>
> On Thu, Jul 6, 2017 at 9:38 AM, Arik Hadas <ahadas at redhat.com> wrote:
>
>>
>>
>> On Wed, Jul 5, 2017 at 9:36 PM, Shirly Radco <sradco at redhat.com> wrote:
>>
>>>
>>>
>>> --
>>>
>>> SHIRLY RADCO
>>>
>>> BI SOFTWARE ENGINEER,
>>>
>>> Red Hat Israel <https://www.redhat.com/>
>>>
>>> sradco at redhat.com
>>>  <https://red.ht/sig>
>>>  <https://redhat.com/summit>
>>>
>>>
>>> On Wed, Jul 5, 2017 at 6:35 PM, Arik Hadas <ahadas at redhat.com> wrote:
>>>
>>>>
>>>>
>>>> On Wed, Jul 5, 2017 at 5:57 PM, Roy Golan <rgolan at 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 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 at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/devel
>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Devel mailing list
>>>> Devel at ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/devel
>>>>
>>>
>>>
>>
>> _______________________________________________
>> Devel mailing list
>> Devel at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/devel
>>
>
>
> _______________________________________________
> Devel mailing list
> Devel at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/devel/attachments/20170706/05f87a16/attachment-0001.html>