[z/OS]

Monitoring and controlling 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.

You 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 you 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 control function consists of panels, commands and programs, two synchronization queues, channel command queues, and the channel definitions. This topic is a brief description of the components of the channel control function.
  • 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, you 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

Managing your channels on z/OS

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

Table 1. Channel tasks
Task to be performed MQSC command
Define a channel DEFINE CHANNEL
Alter a channel definition ALTER CHANNEL
Display a channel definition DISPLAY CHANNEL
Delete a channel definition DELETE CHANNEL
Start a channel initiator START CHINIT
Stop a channel initiator STOP CHINIT
Display channel initiator information DISPLAY CHINIT
Start a channel listener START LISTENER
Stop a channel listener STOP LISTENER
Start a channel START CHANNEL
Test a channel PING CHANNEL
Reset message sequence numbers for a channel RESET CHANNEL
Resolve in-doubt messages on a channel RESOLVE CHANNEL
Stop a channel STOP CHANNEL
Display channel status DISPLAY CHSTATUS
Display cluster channels DISPLAY CLUSQMGR