Adding a cluster transmit queue to isolate cluster message traffic sent from a gateway queue manager
Modify the configuration of overlapping clusters that use a gateway queue manager. After the modification messages are transferred to an application from the gateway queue manager without using the same transmission queue or channels as other cluster messages. The solution uses an additional cluster transmission queue to separate message traffic to a single queue manager in a cluster.
Before you begin
- The gateway queue manager must be on IBM® WebSphere® MQ 7.5, or later.
- Construct the overlapping clusters shown in Client-server application deployed to hub and spoke architecture using IBM MQ clusters in Creating two-overlapping clusters with a gateway queue manager by following the steps in that task.
About this task
On the gateway queue manager, QM1
, add a transmission queue and set its queue attribute CLCHNAME
. Set CLCHNAME
to the name of the cluster-receiver channel on QM3
; see Figure 1.
- It requires fewer additional definitions.
- It supports workload balancing between multiple copies of the target queue,
Q1
, on different queue managers in the same cluster,CL2
. - The gateway queue manager switches automatically to the new configuration when the channel restarts without loosing any messages.
- The gateway queue manager continues to forward messages in the same order as it received them. It does so, even if the switch takes place with messages for the queue
Q1
atQM3
still onSYSTEM.CLUSTER.TRANSMIT.QUEUE
.
The configuration to isolate cluster message traffic in Figure 1 does not result in as great an isolation of traffic as the configuration using remote queues in Adding a remote queue definition to isolate messages sent from a gateway queue manager. If the queue manager QM3
in CL2
is hosting a number of different cluster queues and server applications, all those queues share the cluster channel, CL2.QM3
, connecting QM1
to QM3
. The additional flows are illustrated in Figure 1 by the gray arrow representing potential cluster message traffic from the SYSTEM.CLUSTER.TRANSMIT.QUEUE
to the cluster-sender channel CL2.QM3
.
The remedy is to restrict the queue manager to hosting one cluster queue in a particular cluster. If the queue manager is already hosting a number of cluster queues, then to meet this restriction, you must either create another queue manager, or create another cluster; see Adding a cluster and a cluster transmit queue to isolate cluster message traffic sent from a gateway queue manager.
Procedure
What to do next
Test the separate transmission queue by sending a message from QM2
to Q1
on QM3
using the queue alias definition Q1A
- Run the sample program amqsput on
QM2
to put a message.
C:\IBM\MQ>amqsput Q1A QM2
Sample AMQSPUT0 start
target queue is Q1A
Sample request message from QM2 to Q1 using Q1A
Sample AMQSPUT0 end
- Run the sample program amqsget to get the message from
Q1
onQM3
C:\IBM\MQ>amqsget Q1 QM3
Sample AMQSGET0 start
message <Sample request message from QM2 to Q1 using Q1A>
no more messages
Sample AMQSGET0 end