Overview of cluster components
Figure 2 shows the components of a cluster called CLUSTER.
- In this cluster there are three queue managers, QM1, QM2, and QM3.
- QM1 and QM2 host repositories of information about the queue managers
in the cluster. They are referred to as full repository
queue managers. (The repositories are represented in the diagram by the
shaded cylinders.)
- QM2 and QM3 host some queues that are accessible to any other queue manager
in the cluster. These are called cluster queues. (The
cluster queues are represented in the diagram by the shaded queues.)
As
with distributed queuing, an application uses the MQPUT call to put a message
on a cluster queue at any queue manager. An application
uses the MQGET call to retrieve messages from a cluster queue on the local queue manager.
- Each queue manager has a definition for the receiving end of a channel
called TO.qmgr on which it can receive messages. This is a cluster-receiver channel. A cluster-receiver channel is similar to a
receiver channel used in distributed queuing, but in addition to carrying
messages this channel can also carry information about the cluster.
- Each queue manager also has a definition for the sending end of a channel,
which connects to the cluster-receiver channel of one of the full repository
queue managers. This is a cluster-sender channel.
In Figure 2, QM1 and QM3 have cluster-sender channels connecting
to TO.QM2. QM2 has a cluster-sender channel connecting to TO.QM1. A cluster-sender
channel is similar to a sender channel used in distributed queuing, but in
addition to carrying messages this channel can also carry information about
the cluster.
Once both the cluster-receiver end and the cluster-sender
end of a channel have been defined, the channel starts automatically.