Hi Everyone,
Consider a Geode cluster in which some nodes contain a particular type of
data which is critical to the business and hosts a large amount of data.
Some nodes may host data which is not critical to the business and hosts
less amount of data compared to the previous type of nodes.
If both the type of nodes are going through some operation which is making
them unresponsive, the former type of node may take a couple of seconds
extra than the later to respond.
In this scenario is it fair to give the same member-timeout to all the
members?
What if we want to wait for a little longer time for such nodes.
In the present configuration in geode, we cannot wait a little longer for
some nodes when compared to do this although we can configure different
member-timeout for all the nodes. But i think no one will ever configure
different timeouts for each node because those member-timeouts will be used
to monitor their neighbors.
In this solution, we all do is wait for the suspected member-timeout
instead of its own timeout during final check.
It has no backward implications also, if somebody wants to use the
existing behavior they will continue to use the same member-timeouts for
all the nodes. So the behavior of the system is preserved.
If you have any concerns in this solution, please let me know.
Thanks,
Aravind Musigumpula
-----Original Message-----
From: Aravind Musigumpula
Sent: Monday, December 18, 2017 6:55 PM
To: dev@geode.apache.org
Subject: RE: Monitor the neighbour JVM using neihbour's member-timeout
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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