Monitor and control channels on z/OS

Use the DQM commands and panels to create, monitor, and control the channels to remote queue managers.

Each z/OS queue manager has a DQM program (the channel initiator ) for controlling interconnections to remote queue managers using native z/OS facilities.

The implementation of these panels and commands on z/OS is integrated into the operations and control panels and the MQSC commands. No differentiation is made in the organization of these two sets of panels and commands.

We can also enter commands using Programmable Command Format (PCF) commands. See Automating administration tasks for information about using these commands.

The information in this section applies in all cases where the channel initiator is used for distributed queuing. It applies whether we are using queue sharing groups, or intra-group queuing.

The DQM channel control function

For an overview of the distributed queue management model, see Message sending and receiving.

• The channel definitions are held as objects in page set zero or in Db2, like other IBM MQ objects in z/OS.
• You use the operations and control panels, MQSC commands, or PCF commands to:
  • Create, copy, display, alter, and delete channel definitions
  • Start and stop channel initiators and listeners
  • Start, stop, and ping channels, reset channel sequence numbers, and resolve in-doubt messages when links cannot be re-established
  • Display status information about channels
  • Display information about DQM

  In particular, we can use the CSQINPX initialization input data set to issue your MQSC commands. This set can be processed every time you start the channel initiator. For more information, see Initialization commands.

• There are two queues (SYSTEM.CHANNEL.SYNCQ and SYSTEM.QSG.CHANNEL.SYNCQ) used for channel re-synchronization purposes. Define these queues with INDXTYPE(MSGID) for performance reasons.
• The channel command queue (SYSTEM.CHANNEL.INITQ) is used to hold commands for channel initiators, channels, and listeners.
• The channel control function program runs in its own address space, separate from the queue manager, and comprises the channel initiator, listeners, MCAs, trigger monitor, and command handler.
• For queue sharing groups and shared channels, see Shared queues and queue sharing groups.
• For intra-group queuing, see Intra-group queuing

Manage your channels on z/OS

Use the links in the following table for information about how to manage your channels, channel initiators, and listeners:

• Use the panels and the commands
  We can use the MQSC commands, the PCF commands, or the operations and control panels to manage DQM.
• Defining a channel
  We can define a channel using MQSC commands or using the operations and control panels.
• Altering a channel definition
  We can alter a channel definition using MQSC commands or using the operations and control panels.
• Display a channel definition
  We can display a channel definition using MQSC commands or using the operations and control panels.
• Delete a channel definition
  We can delete a channel definition using MQSC commands or using the operations and control panels.
• Display information about the channel initiator
  We can display information about the channel initiator using MQSC commands or using the operations and control panels.
• Securing a channel
  We can secure a channel using MQSC commands or using the operations and control panels.
• Starting a channel initiator
  We can start a channel initiator using MQSC commands or using the operations and control panels.
• Stopping a channel initiator
  We can stop a channel initiator using MQSC commands or using the operations and control panels.
• Starting a channel listener
  We can start a channel listener using MQSC commands or using the operations and control panels.
• Stopping a channel listener
  We can stop a channel listener using MQSC commands or using the operations and control panels.
• Starting a channel
  We can start a channel using MQSC commands or using the operations and control panels.
• Starting a shared channel
  To start a shared channel, and keep it on a nominated channel initiator, use disposition = S (on the START CHANNEL command, specify CHLDISP(FIXSHARED)).
• Testing a channel
  We can test a channel using MQSC commands or using the operations and control panels.
• Resetting message sequence numbers for a channel
  We can reset message sequence numbers for a channel using MQSC commands or using the operations and control panels.
• Resolving in-doubt messages on a channel
  We can resolve in-doubt messages on a channel using MQSC commands or using the operations and control panels.
• Stopping a channel
  We can stop a channel using MQSC commands or using the operations and control panels.
• Display channel status
  We can display channel status by using MQSC commands, or by using the operations and control panels.
• Display cluster channels
  We can display cluster channels using MQSC commands or using the operations and control panels.
• Preparing IBM MQ for z/OS to use the zEnterprise Data Compression Express facility
  The zEnterprise Data Compression (zEDC) Express facility is available for certain models of IBM Z machines, using a minimum z/OS level of z/OS Version 2.1.

Parent topic: Set up communications with other queue managers

Related concepts

• Use the panels and the commands
• Set up communications with other queue managers
• Set up IBM MQ for z/OS
• Set up communication for z/OS
• Preparing IBM MQ for z/OS for DQM with queue sharing groups
• Set up communication for IBM MQ for z/OS using queue sharing groups

Related tasks

• Configure distributed queuing