Re: [jgroups-dev] Reception of Multicast message stopped after network restart

[email protected] wrote:
> How would nodes which stop receiving messages trigger a UDP storm ?
>
>
> DF> This is still under investigation, but quick look at tcpdump show 
> enndless NAKACK retransmission and
> lots of SUSPECT from all other nodes that will never stop until all 
> nodes on the server is restarted.
>
>
>> We have been able to reproduce the issue with this very simple
>> scenario on Linux 5.3 64bits.
>> Scenario: A and B join the same cluster, when everything is stable, We
>> perform a network restart on server A {/sbin/service network restart}.

I ran this scenario on my Fedora based cluster as well: service network 
start / stop on A (coord of cluster {A,B}). What happened was:

    * A was suspected by B and excluded
    * A came back
    * A and B merged back into 1 cluster

This was done with UDP as transport (using udp.xml shipped with JGroups)


> I don't think this works: an ifconfig down/up is not something that a
> socket would survive ! Can you use IP Bonding ?

I was wrong: apparently this works, at least on Linux and with UDP as 
transport !


>> For an unknown raison node A stop receiving Multicast from B resulting
>> on an unstable cluster were members could not join the same cluster
>> anymore. We are reproducing this issue 100% of the time.


Well, maybe you need to write down the exact steps, and the following info:

    * OS / version
    * JGroups version
    * Your config XML file used



-- 
Bela Ban
Lead JGroups / Clustering Team
JBoss

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