Before you can create a queue manager, there are several points you need to consider (especially in a production environment). Work through the following checklist:
One way of ensuring uniqueness is to prefix each queue manager name with its own unique node name. For example, if a node is called ACCOUNTS, you can name your queue manager ACCOUNTS.SATURN.QUEUE.MANAGER, where SATURN identifies a particular queue manager and QUEUE.MANAGER is an extension you can give to all queue managers. Alternatively, you can omit this, but note that ACCOUNTS.SATURN and ACCOUNTS.SATURN.QUEUE.MANAGER are different queue manager names.
If you are using WebSphere MQ for communication with other enterprises, you can also include your own enterprise name as a prefix. This is not done in the examples, because it makes them more difficult to follow.
In production systems, many processors can be exploited with a single queue manager, but larger server machines might run more effectively with multiple queue managers.
Specifying a queue manager as the default replaces any existing default queue manager specification for the node.
Changing the default queue manage can affect other users or applications. The change has no effect on currently-connected applications, because they can use the handle from their original connect call in any further MQI calls. This handle ensures that the calls are directed to the same queue manager. Any applications connecting after you have changed the default queue manager connect to the new default queue manager. This might be what you intend, but you should take this into account before you change the default.
Creating a default queue manager is described in Creating a default queue manager.
It is important to have a dead-letter queue on each queue manager in your network. If you do not define one, errors in application programs might cause channels to be closed, and replies to administration commands might not be received.
For example, if an application tries to put a message on a queue on another queue manager, but gives the wrong queue name, the channel is stopped and the message remains on the transmission queue. Other applications cannot then use this channel for their messages.
The channels are not affected if the queue managers have dead-letter queues. The undelivered message is simply put on the dead-letter queue at the receiving end, leaving the channel and its transmission queue available.
When you create a queue manager, use the -u flag to specify the name of the dead-letter queue. You can also use an MQSC command to alter the attributes of a queue manager that you have already defined to specify the dead-letter queue to be used. See Altering queue manager attributes for an example of the MQSC command ALTER.
When you create a queue manager, use the -d flag to specify the name of the default transmission queue. This does not actually create the queue; you have to do this explicitly later on. See Working with local queues for more information.
In a development environment, the default logging parameters should be adequate. However, you can change the defaults if, for example:
Once you have set the logging parameters, some of them can only be changed by deleting the queue manager and recreating it with the same name but with different logging parameters.
For more information about logging parameters, see Recovery and restart.
These shared memory problems do not occur if the different logical volumes are created such that they have different minor device numbers.
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