Channels implemented as queue manager objects

This section gives information in relation to the move of channels to queue manager objects in WebSphere® MQ Version 6.0.

In previous versions of WebSphere MQ, channels on distributed platforms have been stored collectively in a single channel definition file and secured by mqm or QMQMADM permissions. In WebSphere MQ Version 6.0 channels are implemented as queue manager objects in a similar way to objects such as queues and namelists. Two of the main advantages are that channel definitions are now recoverable from media images stored in the queue manager logs and that authority to channel objects can be granted on a per object basis like any other object. Start of changeTo be able to recover a channel from a media image, you must first record an image of the channel. If you issue the rcdmqimg command with the -t all parameter, this will happen automatically. If you specify particular types of object, you must add commands to record channel and clntconn objects. There are two new object authorities relevant to channel objects; control (ctrl) and control extended (ctrlx). You must have the appropriate authority in order to start, stop, ping, resolve and reset channels. Any user with ALLADM authority has the required authorities implicitly. End of changeDetails of changes to media recovery and authority commands to support the new objects can be found in the WebSphere MQ System Administration Guide.

Migration of the channels

Migration to queue manager objects is carried out the first time the queue manager is started after installing WebSphere MQ Version 6.0. A message Start of change(AMQ8047)End of change summarizing the total number of channels successfully migrated is displayed and is also written to the queue manager error logs. Start of changeIf channel migration fails, set the AMQ_MIGFORCE_CHANNEL environment variable to force remigration the next time the queue manager is started.End of change Once migration has completed, the channel definition file is renamed from amqrfcda.dat to amqrfcda.old or from AMQRFCD4(AMQRFCD4) to AMQRFOLD(AMQRFOLD) on iSeries™.

Reverting to a previous version of WebSphere MQ

If you need to uninstall WebSphere MQ Version 6.0 and revert to an earlier version of WebSphere MQ, you will need to rename the channel definition files from amqrfcda.old to amqrfcda.dat or from AMQRFOLD(AMQRFOLD) to AMQRFCD4(AMQRFCD4) on iSeries. This will configure your channels to the state that they were in prior to the installation of WebSphere MQ Version 6.0. Any changes made to the channel definitions after the installation of WebSphere MQ Version 6.0 will be lost.