Plan the distributed queues and clusters

We can manually connect queues hosted on distributed queue managers, or we can create a queue manager cluster and let the product connect the queue managers for you. To choose a suitable topology for your distributed messaging network, you need to consider your requirements for manual control, network size, frequency of change, availability and scalability.

Before you begin

This task assumes that you understand what distributed messaging networks are, and how they work. For a technical overview, see Distributed queuing and clusters.

About this task

To create a distributed messaging network, we can manually configure channels to connect queues hosted on different queue managers, or we can create a queue manager cluster. Clustering enables queue managers to communicate with each other without the need to set up extra channel definitions or remote queue definitions, simplifying their configuration and management.

To choose a suitable topology for your distributed publish/subscribe network, you need to consider the following broad questions:

• How much manual control do you need over the connections in your network?
• How big will your network be?
• How dynamic will it be?
• What are your availability and scalability requirements?

Procedure

• Consider how much manual control you need over the connections in your network.

  If we only need a few connections, or if individual connections need to be very precisely defined, you should probably create the network manually.

  If you need multiple queue managers that are logically related, and that need to share data and applications, you should consider grouping them together in a queue manager cluster.

• Estimate how big your network needs to be.
  1. Estimate how many queue managers you need. Bear in mind that queues can be hosted on more than one queue manager.
  2. If you are considering using a cluster, add two extra queue managers to act as full repositories.
  For larger networks, manual configuration and maintenance of connections can be very time consuming, and you should consider using a cluster.
• Consider how dynamic the network activity will be.

  Plan for busy queues to be hosted on performant queue managers.

  If you expect queues to be frequently created and deleted, consider using a cluster.

• Consider your availability and scalability requirements.
  1. Decide whether you need to guarantee high availability of queue managers. If so, estimate how many queue managers this requirement applies to.
  2. Consider whether some of your queue managers are less capable than others.
  3. Consider whether the communication links to some of your queue managers are more fragile than to others.
  4. Consider hosting queues on multiple queue managers.

  Manually configured networks and clusters can both be configured to be highly available and scalable. If we use a cluster, you need to define two extra queue managers as full repositories. Having two full repositories ensures that the cluster continues to operate if one of the full repositories becomes unavailable. Make sure that the full repository queue managers are robust, performant, and have good network connectivity. Do not plan to use the full repository queue managers for any other work.

• Based on these calculations, use the links provided to help you decide whether to manually configure connections between queue managers, or to use a cluster.

What to do next

You are now ready to configure your distributed messaging network.