ActiveMQ - network of multiple brokers configuration

I'm trying to s开发者_Python百科et up three brokers in a network for load balancing -- clients and producers can connect to any of these brokers.

Questions:

1. What is the recommended topology to use to network these brokers? More specifically, what is the networkConnector configuration to use on each of these brokers? should duplex setting be enabled? (I guess duplex setting depends on the topology we choose)

   A->B->C->A      or      A<-->B<-->C<-->A

2. Client should use failover protocol to connect to these brokers, right? e.g. failover://(tcp://b1:6161, tcp://b2:6161, tcp://b3:6161)

3. Any duplicate message handling required on the client side in case of restarts? See http://forum.springsource.org/showthread.php?108461-Failover-issue-in-ActiveMQ -- not clear why duplicate message issue exists here

4. Ideally we want to set up topology as shown in this post http://edelsonmedia.com/?p=143 -- not clear how to set up networkConnector on masters and slaves.

1.) I can't actually recommend a topology. This choice depends on the number of hops (between the broker where the messages enters the cluster and the broker where the consumer conects to) you can accept. In a heave traffic scenario every hop adds to the network load. In my company we use a hypercube network (every broker knows every other broaker) and it works great.

Generaly you should make sure that your node configurations are as similar as possible. Using duplex makes sure you have less connections to configure (since the connection from B to A is already part of the duplex connection from A to B) but it introduce a large number of differences into your config file.

Personaly i created my own start script for ActiveMQ that auto-generated the connection config based on the dns names of my cluster (mycluster-01 to 06).

2.) yes. You might want to add ?randomize=false if you want to make sure the client uses the first entry in the list.

3.) Duplicate entries can happen if there are failures during message transport or as race conditions during heavy load. In general one message only is owned by one broker.

4.) dont set up network connectors between masters and slaves (REALLY DONT). Use the pure Master Slave feature of activeMQ and configure the master for each slave (you don't have to configure anything on the masters). For the all Masters configure NetworkConnections to the other Masters with failover to their slaves) http://activemq.apache.org/pure-master-slave.html