Hi Aravind,
Your arguments about the final-check seem sound to me. I put some
further comments on your PR.
Regards,
Bruce S.
On 12/18/17 5:25 AM, Aravind Musigumpula wrote:
Hi Community,
Can you please give your suggestions on the below solution.
I have raised a pull request for the same :
https://github.com/apache/geode/pull/1075 .
Thanks,
Aravind Musigumpula
-----Original Message-----
From: Aravind Musigumpula
Sent: Friday, November 03, 2017 3:23 PM
To: dev@geode.apache.org
Subject: RE: Monitor the neighbour JVM using neihbour's member-timeout
Thanks Bruce for suggestions, I will change the new variables from
InternalDistributedMember to NetView and do changes related to backward
compatibility.
Now I know that there is another way that member can be removed from the view
i.e if any member is sending a message and waits for ack-wait-threshold, if
there is no response from the target the sender will do final check and remove
it from the view if there is still no response.
But I don't understand how deprecating the settings member-timeout,
ack-wait-threshold, ack-severe-alert-threshold into one will solve the problem.
The main problem is that we want a member to survive in the view for longer
time than others.
If we deprecate the settings into one setting and pass the setting to
monitoring member(say A), then it will use the target member(say B which we
want to survive in view for longer time) timeout for health monitoring and
ack-wait-threshold to wait for the response for any message before doing final
check.
But what if some other member(say C) which is monitoring any other member(say
D) have the member-timeout and ack-wait-threshold some smaller values. So if
member C messages to B, C uses the smaller value of ack-wait-threshold(which is
of member D) to get a response and does the final check again on basis of
smaller member-timeout. So still member B can be kicked out of the view in
small amount of time.
I think this can be solved simply if we use the member-timeout of suspected
member in the final check where we establish TCP connection. We don't need to
club those three settings as well. We can set the member-timeout of a
particular member to a higher value and the member which monitors it uses its
own member-timeout as it is now, but during the final check it uses the
suspected member-timeout(which is a greater value). The final check is common
place in both the no heartbeat scenario and no response for a message scenario.
Are there any concerns around this new proposal ?
Thanks,
Aravind Musigumpula
-----Original Message-----
From: Bruce Schuchardt [mailto:bschucha...@pivotal.io]
Sent: Thursday, September 07, 2017 10:42 PM
To: dev@geode.apache.org
Subject: Re: Monitor the neighbour JVM using neihbour's member-timeout
I think this might be an acceptable change though I doubt many people would
find it useful.
It's already possible to set different member-timeouts on each node of the
distributed system but the meaning of the setting is the inverse of what's
proposed here, so having the current setting be different in each node is
pretty useless.
I think the initiation of suspect processing ought to be addressed if we make
this change. The ack-wait-threshold and ack-severe-alert-threshold aren't
based on the member-timeout but ought to be. This would make it possible to
initiate suspect processing with different timing for different nodes. It
would still leave the question of slow backup operations hanging: If you're
waiting for one node that's blocked waiting for a response from another node
(say a node holding a backup
bucket) you are going to initiate suspect processing on the node you're waiting on
& not those other (backup) nodes.
Rolling upgrade will also be a problem since old members aren't going to cough
up their member-timeout settings. What should be used as a membership timeout
for the old members during an upgrade?
If we proceed with this idea I'd prefer that we deprecate member-timeout,
ack-wait-threshold and ack-severe-alert-threshold and have new settings with the
"ack" settings being multiples of the new membership timeout setting.
Concerning the PR, it isn't acceptable in its current form.
InternalDistributedMember identifiers are often transmitted in messages and
increasing their size affects performance. Any new member attributes need to
be added to NetView instead of InternalDistributedMember.
On 8/22/17 12:35 AM, Aravind Musigumpula 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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