From MQ 9.2.5, and now in 9.3.0, newly defined queue managers will have their Bootstrap Dataset (BSDS) created with a 64-Bit RBA by default
The 48-Bit RBA is not always suitable for today’s workloads. Several customers have found they run over their log RBA frequently with the sorts of workloads they drive. This means they need to shut the queue managers down to reset the RBA which is obviously disruptive. They therefore require the 64-Bit RBA to be able to run their workloads. To avoid this disruption customers create new queue managers and immediately convert them to 64-Bit RBA. This conversion can be quite a lengthy process.
The process is as follows:
- Stop the queue manager if running
- Move the current BSDS to a different dataset, using IDCAMS ALTER. For example ++HLQ++.V1.BSDS
- Create a new empty BSDS at ++HLQ++.BSDS using the definitions that can be found in CSQ4BSDS JCL provided in MQ
- Create the JCL that invokes the CSQJUCNV utility, specifying the correct parameters and pointing it at both the old and new BSDS locations.
- Run the JCL
- Ensure that the job runs successfully
- Start the queue manager, ensure that the converted BSDS is successful and that the queue manager is able to start up correctly.
- Remove or archive the old BSDS as it is no longer being used. (or keep it)
From MQ 9.2.5 onwards none of these steps will be required when defining a new queue manager. There are no performance or other benefits to use the 48-Bit RBA and using 64-Bit RBA is more suited towards modern workloads. Therefore, there is no longer a need to define queue managers with a 48-Bit RBA.
Queue Managers defined before MQ 9.2.5 whose BSDS has not yet been converted will continue to use 48-Bit RBA until converted using the CSQJUCNV utility.