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From Udo Kohlmeyer <ukohlme...@pivotal.io>
Subject Re: DISCUSS : Monitor the neighbour JVM using neihbour's member-timeout (GEODE-3411)
Date Fri, 01 Sep 2017 16:34:47 GMT
Hi there Aravind,

I have a singular problem with this approach.

If a some members are designated to do more work, and don't have time to 
respond to the cluster that they are alive using the current member 
timeout, then they are not available to accept data. Which means they 
are not effective members of the cluster and we cannot count on them to 
host data or replicates.

This setting is there to safe guard the cluster against non-responsive 
members that cause the whole cluster to be unhealthy if left unchecked 
for too long. This can lead to potential data loss....

If you feel that the member timeout is too short for some members, why 
don't you increase the current member timeout?

My opinion is a -1 for changing the current behavior.

--Udo

On 9/1/17 03:46, Aravind Musigumpula wrote:
> Hi Brian,
>
> This will help if the user has some member doing a heavy duty when compared to others,
in this case we need to give such member some extra time to that member.
>
> Thanks,
> Aravind Musigumpula
>
>
> -----Original Message-----
> From: Brian Baynes [mailto:bbaynes@pivotal.io]
> Sent: Friday, September 01, 2017 4:39 AM
> To: dev@geode.apache.org
> Subject: Re: DISCUSS : Monitor the neighbour JVM using neihbour's member-timeout (GEODE-3411)
>
> Hi, Aravind.
>
> Can you help me understand why this might be a useful feature for Geode?  I see that
your needs require it, but why would users in general want to allow longer timeouts for some
members?  This is a significant change with backward-compatibility implications, so would
be good for the community to understand the potential benefit.
>
> Thanks!
> Brian
>
> On Mon, Aug 28, 2017 at 12:20 AM, Aravind Musigumpula < Aravind.Musigumpula@amdocs.com>
wrote:
>
>> Hi Team,
>>
>> We have a requirement to configure  different member timeout for
>> different members as we need some members to survive in the view for
>> longer time than the other the members before being kicked out of the
>> view in case they aren't responding.
>>
>>
>> 1.       Now with the current monitoring system it is not possible to
>> determine when the member will be kicked out of the view if we
>> configure different member-timeout's for some required members.
>>
>> 2.       Because if a member is not responding to any heartbeat requests,
>> the member who is monitoring the non-responding member will initiate
>> check member request.
>>
>> 3.       In this check member request monitoring member pings the
>> non-responding member and waits for member-timeout of monitoring
>> member for a response.
>>
>> 4.       If still there is no response, it will initiate a final suspect
>> request to coordinator where the coordinator does the final check
>> waiting for coordinators member-timeout.
>>
>> 5.       If coordinator did not get any response, it will remove the
>> non-responding member from the view and publishes it.
>>
>> 6.       So, Here the time period for removing a member depends on its
>> monitoring member's and coordinator's timeout. But the monitoring
>> member depends on the view but it may change from time to time.
>>
>> So, now when a monitoring-member doing the check on a member, if we
>> wait for the non-responding member's timeout instead of the monitoring
>> member-timeout, then the time when the non-responding member will be
>> removed from the view depends on its own member-timeout and the
>> coordinators member-timeout.
>> Hence we can configure different member-timeout for the required members.
>>
>> I created a pull request based on the above scenario:
>> https://github.com/apache/geode/pull/717
>>
>> Is the above approach correct? Do we have any concerns around this area?
>> Please give your insights on this issue.
>>
>> Thanks,
>> Aravind Musigumpula
>>
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>>
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