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From Rainer Jung <>
Subject Re: Balancer persist and inherit stuff in trunk
Date Wed, 09 Jan 2013 12:26:04 GMT
On 08.01.2013 17:09, Jim Jagielski wrote:
> Rainer, does the below address your concern and make
> it OK that the current behavior acts the way it does
> and we're OK to keep it that way.

Yes sort of. We now know/remember why there are subtleties and since
some statistical counters are dual purpose - statistics/monitoring and
LB decision data it seems we need to give up a 100% consistency goal.
I'm OK with that as it is now.

Did you have a look at the other topic about the "Used" shm slot counter?



> On Jan 8, 2013, at 10:25 AM, Jim Jagielski <> wrote:
>> Yeppers...
>> actually, transferred and read *are* persisted, it's just
>> that the bytraffic lbmethod is smart enough to know that
>> when the config is changed, those counters need to
>> be reset and, by default, a restart is a "change".
>> Since elected is never used for any sort of lbmethod,
>> it never is reset and so the persist "holds".
>> So the idea is that lbmethods should reset any potential
>> persisted values iff it makes sense for that lbmethod.
>> bytraffic resets transferred/read but byrequests doesn't,
>> for example.
>> On Jan 8, 2013, at 9:49 AM, Jim Jagielski <> wrote:
>>> Hold on a tic... let me go thru my notes. I seem to recall
>>> an issue I hit.
>>> On Jan 8, 2013, at 9:28 AM, Jim Jagielski <> wrote:
>>>> +1 for both being reset...
>>>> On Jan 7, 2013, at 4:40 AM, Rainer Jung <> wrote:
>>>>> On 06.01.2013 17:48, Jim Jagielski wrote:
>>>>>> I had thought that I has responded to that orig
>>>>>> email that both below issues where "by design"
>>>>>> but could be adjusted if need be or desired.
>>>>>> I have no opinions either way, but to be Used seems
>>>>>> more session based and Elected is more long-term
>>>>>> statistical.
>>>>> Hmmm, but the "Used" field should give information about shm slots
>>>>> occupied by configured balancers. Isn't the info (=0) wrong after a restart?
>>>>> Concerning the long term statistical values I'm undecided like you, but
>>>>> I think we should handle them in a consistent way, so "traffic" and
>>>>> "elected" should either be both persisted or both reset.
>>>>> Regards,
>>>>> Rainer
>>>>>> On Jan 5, 2013, at 1:41 PM, Rainer Jung <>
>>>>>>> On 04.01.2013 19:48, Jim Jagielski wrote:
>>>>>>>> Have people had a chance to test, review and try the balancer
>>>>>>>> persist and inheritance stuff in trunk? I want to make
>>>>>>>> sure that we have some level of verification and agreement
>>>>>>>> there before I work on the backports for 2.4 ;)
>>>>>>> I didn't see any changes with respect to two of my original comments:
>>>>>>> The "Used" counters (number of shared mem slots) in balancer
>>>>>>> drops to "0" after restart/reboot´with persist on. This seems
>>>>>>> Not that "Used" does *not* have anything to do with request counting.
>>>>>>> Second the "Elected" counter is persisted but e.g. the traffic
>>>>>>> not. This seems somewhat inconsistent. I have no strong opinion
>>>>>>> to persist statistics or not, but we might want to behave consistently.
>>>>>>> I did not observe any functional changes after my Mail from Dec.
14, right?
>>>>>>> Regards,
>>>>>>> Rainer

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