Reverting a queue manager to an earlier version on UNIX and Linux

On UNIX and Linux, we can revert a queue manager to an earlier version of the product from a later version, if you have made a backup of the system or queue manager. If you have started the queue manager and processed any messages, or changed the configuration, the task cannot give you any guidance on reverting the current state of the queue manager.

Before starting

1. We must have made a backup of the system or queue manager before you upgraded to the later version. For more information see Backing up and restoring IBM MQ queue manager data
2. If any messages were processed after starting the queue manager, we cannot easily undo the effects of processing the messages. We cannot revert the queue manager to the earlier version of the product in its current state. The task cannot give you any guidance how to deal with subsequent changes that have occurred. For example, messages that were indoubt in a channel, or in a transmission queue on another queue manager, might have been processed. If the queue manager is part of a cluster, then configuration messages and application messages might have been exchanged.
3. If we are running on a server with multiple IBM MQ installations, we must identify the installation. Make sure that the commands you enter run against the correct installation; see setmqenv.

When you revert to a earlier version of a queue manager, you revert the queue manager to its earlier code level. Queue manager data is reverted to the state it was in when the queue manager was backed up.

Procedure

1. Log in as a user in group mqm.
2. Stop all applications using the IBM MQ installation.

   If we use the Managed File Transfer (MFT) component, ensure that any MFT agents have finished all of the file transfers that they were engaged in. There should be no incomplete transfers associated with the agents, and their SYSTEM.FTE.STATE queues should contain no messages.

3. End all the activity of queue managers associated with the IBM MQ installation.
   1. Run the dspmq command to list the state of all the queue managers on the system.

      Run either of the following commands from the installation that we are updating:

      dspmq -o installation -o status
      dspmq -a
      

      dspmq -o installation -o status displays the installation name and status of queue managers associated with all installations of IBM MQ.

      dspmq -a displays the status of active queue managers associated with the installation from which the command is run.

   2. Use the MQSC command DISPLAY LSSTATUS to list the status of listeners associated with a queue manager, as shown in the following example:

      echo "DISPLAY LSSTATUS(*) STATUS" | runmqsc QmgrName
      

   3. Run the endmqm command to stop each running queue manager associated with this installation.

      The endmqm command informs an application that the queue manager it is connected to is stopping; see Stopping a queue manager.

      For the maintenance to proceed, applications must respond to an endmqm command by disconnecting from the queue manager and releasing any IBM MQ libraries they have loaded. If they do not, you must find another way to force applications to release IBM MQ resources, such as by stopping the applications.

      You must also stop applications that are using the client libraries that are part of the installation. Client applications might be connected to a different queue manager, running a different installation of IBM MQ. The application is not informed about queue managers in the current installation being shut down.

      Any applications that continue to have IBM MQ shared libraries from the installation loaded prevent you applying IBM MQ maintenance. An application might disconnect from a queue manager, or be forcibly disconnected, but keep an IBM MQ

      shared library loaded. Note: The topic, Applying maintenance level updates to multi-instance queue managers on Windows, describes how to apply maintenance to a multi-instance queue manager. A multi-instance queue manager can continue to run on one server, while maintenance is applied to another server.
   4. Stop any listeners associated with the queue managers, using the command:

      endmqlsr -m QMgrName
      

4. Restore the system, or IBM MQ and the queue manager.

   If your backup procedure was to save the queue manager data, we must reinstall IBM MQ:

   1. Uninstall the earlier installation.
   2. Reinstall the product from a manufacturing refresh.
   3. Apply the fix pack and interim fixes that restore IBM MQ to its previous level.
   4. Restore the queue manager data from the backup taken before installing the later version.

5. Restart the earlier version queue manager.

What to do next

We might be reverting to a earlier version on a server with multiple IBM MQ installations. If one of the installations is primary, after reverting the earlier version that installation, by default, becomes the primary installation.

We must review how applications connect to an installation. After reverting to the earlier version, some applications might connect to the wrong installation.

Parent topic: Migrating a queue manager on UNIX and Linux

Related information

• Backing up and restoring a queue manager
• BFGSS0023E errors and how to avoid them