Connecting a client to a queue-sharing group

You can connect a client to a queue-sharing group by creating an MQI channel between a client and a queue manager on a server that is a member of a queue-sharing group.

A queue-sharing group is formed by a set of queue-managers that can access the same set of shared queues.

A client putting to a shared queue can connect to any member of the queue-sharing group. The benefits of connecting to a queue-sharing group are possible increases in front-end and back-end availability, and increased capacity. You can connect to a specific queue manager or to the generic interface.

Connecting directly to a queue manager in a queue-sharing group gives the benefit that you can put messages to a shared target queue, which increases back-end availability.

Connecting to the generic interface of a queue-sharing group opens a session with one of the queue managers in the group. This increases front-end availability, because the client queue manager can connect with any queue-manager in the group. You connect to the group using the generic interface when you do not want to connect to a specific queue manager within the queue-sharing group.

The generic interface can be a WLM/DNS group name or a VTAM® generic resource name, or another common interface to the queue-sharing group.

To connect to the generic interface of a queue-sharing group you need to create channel definitions that can be accessed by any queue manager in the group. To do this you need to have the same definitions on each queue manager in the group.

Define the SVRCONN channel as follows:


DEFINE CHANNEL(CHANNEL1) CHLTYPE(SVRCONN) TRPTYPE(TCP) +
MCAUSER(' ') QSGDISP(GROUP)

Channel definitions on the server are stored in a shared DB2® repository. Each queue manager in the queue-sharing group makes a local copy of the definition, ensuring that you will always connect to the correct server-connection channel when you issue an MQCONN or MQCONNX call.

Define the CLNTCONN channel as follows:


DEFINE CHANNEL(CHANNEL1) CHLTYPE(CLNTCONN) TRPTYPE(TCP) +
CONNAME(WLM/DNS groupname) QMNAME(QSG1) +
DESCR('Client-connection to Queue Sharing Group QSG1') QSGDISP(GROUP)

Because the generic interface of the queue-sharing group is stored in the CONNAME field in the client-connection channel, you can now connect to any queue manager in the group, and put to shared queues owned by that group.