JBoss Messaging 1.2 GA will provide a highly sophisticated clustering implementation, far more sophisticated than you'll find in the vast majority of other messaging systems.
It will allow you to smoothly distribute your application load across your cluster, intelligently balancing and utilising each nodes CPU cycles, with no single point of failure, providing a highly scalable and performant clustering implementation.
JBoss Messaging 1.2 GA Clustering will provide the following features:
Distributed queues. Messages sent to a distributed queue while attached to a particular node will be routed to a queue instance on a particular node according to a routing policy.
Distributed topics. Messages sent to a distributed topic while attached at a particular node will be received by subscriptions on other nodes.
Fully reliable message distribution. Once and only once delivery is fully guaranteed. When sending messages to a topic with multiple durable subscriptions across a cluster we guarantee that message reaches all the subscriptions (or none of them in case of failure).
Persistent level reliability guarantee without persistence! By replicating persistent messages between nodes in memory, we can obtain comparable reliability levels to persistenting messages to disk, without actually storing them to disk.
Pluggable routing implementation. The policy for routing messages to a queue is fully pluggable and easily replaceable. The default policy always chooses a queue at the local node if there is one, and if not, it round robins between queues on different nodes.
Intelligent message redistribution policy. Messages are automatically distributed between nodes depending on how fast or slow consumers are on certain nodes. If there are no or slow consumers on a particular queue node, messages will be pulled from that queue to a queue with faster consumers on a different node. The policy is fully pluggable.
Shared durable subscriptions. Consumers can connect to the same durable subscription while attached to different nodes. This allows processing load from durable subscriptions to be distributed across the cluster in a similar way to queues.
High availability and seamless failover. If the node you are connected to fails, you will automatically fail over to another node and will not lose any persistent messages. You can carry on with your session seamlessly where you left off. Once and only once delivery of persistent messages is respected at all times.
What's in the CR1 release?
JBoss Messaging 1.2.0.CR1 contains all features planned for the GA release, with the exception of the "unreliable link scenario" (http://jira.jboss.org/jira/browse/JBMESSAGING-676), whose development is still on-going on a parallel branch.
Please note that this is a candidate release and it possible to contain bugs! We are releasing it to the community, so you can try it out, get familiar with it and feedback your experiences to us so we can improve it and stabilise it.
Thanks for your support!
All the final features are available apart from:
Persistent level reliability guarantee without persistence. There is no option for in memory replication of persistent messages in this release.
Bear in mind you will need to get a bit more "down and dirty" with the configuration in this release, than you would with a GA release.