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Adding a more powerful queue manager that hosts a queue
Follow these instructions to provide additional capacity
by running the inventory system in Los Angeles as well as New York,
where Los Angeles can handle twice the number of messages as New York.
Before you begin
Note: For changes to a cluster to be propagated throughout
the cluster, at least one full repository must always be available.
Ensure that your repositories are available before starting this task.
Scenario:
The INVENTORY cluster has been
set up as described in Adding a queue manager to a cluster. It contains
three queue managers: LONDON and NEWYORK both
hold full repositories, PARIS holds a partial repository
and puts messages from INVENTQ. The inventory application
runs on the system in New York connected to the NEWYORK queue
manager. The application is driven by the arrival of messages on the INVENTQ queue.
A new store is being set up in Los Angeles. To provide additional
capacity, you want to run the inventory system in Los Angeles as well
as New York. The new queue manager can process twice as many messages
as New York.
About this task
Follow these steps to add a more powerful queue manager
that hosts a queue.
Procedure
Decide which full repository LOSANGELES refers
to first.
Every queue manager in a cluster must refer to one or other
of the full repositories to gather information about the cluster.
It builds up its own partial repository. It is of no particular significance
which repository you choose. In this example, NEWYORK is
chosen. Once the new queue manager has joined the cluster it communicates
with both of the repositories.
DEFINE CHANNEL(INVENTORY.NEWYORK) CHLTYPE(CLUSSDR) TRPTYPE(TCP)
CONNAME(NEWYORK.CHSTORE.COM) CLUSTER(INVENTORY)
DESCR('Cluster-sender channel from LOSANGELES to repository at NEWYORK')
Define the CLUSRCVR channel on queue manager LOSANGELES.
Every queue manager in a cluster must define a cluster-receiver
channel on which it can receive messages. On LOSANGELES,
define:
The cluster-receiver channel advertises
the availability of the queue manager to receive messages from other
queue managers in the cluster INVENTORY. Setting CLWLWGHT to
two ensures that the Los Angeles queue manager gets twice as many
of the inventory messages as New York (when the channel for NEWYORK is
set to one).
Alter the CLUSRCVR channel on queue manager NEWYORK.
Ensure that the Los Angeles queue manager gets twice as many
of the inventory messages as New York. Alter the definition of the
cluster-receiver channel.
ALTER CHANNEL(INVENTORY.NEWYORK)
CHLTYPE(CLUSRCVR) CLWLWGHT(1)
Review the inventory application for message affinities.
Before proceeding, ensure that the inventory application
does not have any dependencies on the sequence of processing of messages.
Install the inventory application on the system in Los
Angeles
Define the cluster queue INVENTQ.
The INVENTQ queue, which is already hosted
by the NEWYORK queue manager, is also to be hosted
by LOSANGELES. Define it on the LOSANGELES queue
manager as follows:
DEFINE QLOCAL(INVENTQ) CLUSTER(INVENTORY)
Now that you have completed all the definitions,
if you have not already done so start the channel initiator on WebSphere® MQ for z/OS®. On all platforms, start
a listener program on queue manager LOSANGELES. The
listener program listens for incoming network requests and starts
the cluster-receiver channel when it is needed.
This modification to the cluster was accomplished without
you having to alter the queue managers LONDON and PARIS.
The repositories in these queue managers are updated automatically
with the information they need to be able to send messages to INVENTQ at LOSANGELES.
What to do next
The INVENTQ queue and inventory application
are hosted on two queue managers in the cluster. The configuration
increases their availability, speeds up throughput of messages, and
allows the workload to be distributed between the two queue managers.
Messages put to INVENTQ by either LOSANGELES or NEWYORK are
handled by the instance on the local queue manager whenever possible.
Messages put by LONDON or PARIS are
routed to LOSANGELES or NEWYORK,
with twice as many messages being sent to LOSANGELES.