Thanks Bela.  Just wanted to make sure I was not specing out an architecture out that was fundamentally flawed.  Knowing JBoss is already doing this kind of operation will make others I work with very happy.

Joe Hart

From: Bela Ban <>
To: Joseph Hart <>
Cc: "" <>
Sent: Thursday, June 21, 2012 9:27 AM
Subject: Re: [javagroups-users] Shared Transports and JChannel Creation

Got it. No, there shouldn't be any issues creating additional members
and joining different clusters.

JBoss AS7 clustering does this all the time; by default some services
are inactive, e.g. web session clustering. When a (distributed) WAR is
deployed, only then will the session clustering subsystem be started,
and that means creating a new clustering on an existing shared transport.

On 6/20/12 6:56 PM, Joseph Hart wrote:
> Kind of.
> Assume you have 4 JVMs (vm-1, vm-2, vm-3,&  vm-4).
> 1. All 4 JVM's startup and connect a Cluster named 'main' using a shared UDP transport with the singleton name 'core-tp'.
> 2. At some point in time later vm-1&  vm-2 decide to create a new Cluster named 'sub-1' using the same 'core-tp' shared transport.
> As Cluster 'sub-1' is forming, would you expect any interruption in Cluster 'main'?  May main concern is introducing instability/problems to an existing well formed cluster by randomly attaching a new protocol stack to a running/active shared transport.
> Thanks,
> Joe Hart
> ________________________________
>  From: Bela Ban<>
> To:
> Sent: Wednesday, June 20, 2012 12:03 PM
> Subject: Re: [javagroups-users] Shared Transports and JChannel Creation
> So you're saying that, if we have 2 channels A and B, then we could have
> the following channels created and connected on them:
> - A: 1, 2, 4, 5
> - B: 1,        5
> In other words, B hasn't (yet) joined clusters 2 and 4.
> That's fine, but messages sent by channel A on cluster 2 or 4 will
> simply get discarded by B.
> On 6/20/12 5:41 PM, Joseph Hart wrote:
>> When using shared transports is there any requirement that all JChannel instances that will be sharing a transport be created before any are connected?
>> I am currently looking to build a cluster of roughly 100 nodes.  The plan is to have all nodes join a "main" cluster on startup.  Nodes will then be picked from this "main" cluster to form smaller dynamically named sub-clusters to do specific relatively long lived tasks (at least 30 min).  Ideally I would like to use a single shared UDP transport for the main cluster and all of its sub-clusters.
>> Thanks for your time,
>> Joe Hart

Bela Ban, JGroups lead (