are present. We also check the WebSphere MQ job logs to ensure that there are no errors. You must resolve any errors you encounter before the migration begins. Any problems with the broker, DB2, or WebSphere MQ at WebSphere Business Integration Message Broker V5.0 causes problems when migrating to WebSphere Message Broker V6.0. 25.2.2 Stop the broker You must stop the broker before you create a backup. This ensures that no changes occur between the backup taken and the migration completion. Also, you must stop the broker in order for the migration job to run. 25.2.3 Back up the broker Ensure that the broker database and the broker registry are successfully backed up before the broker is migrated. This allows the broker to get restored to the current WebSphere Business Integration Message Broker V5.0 level, if required. Important: Any change made to the broker database or the broker registry after the backup has taken place (such as new subscriptions that are made or new resources that are deployed) is lost if the backup is restored. For details about how to back up the broker on z/OS, refer to Chapter 19, "Backing up the WebSphere Business Integration Message Broker V5.0 domain" on page 339. 25.2.4 Check the system requirements The system requirements for WebSphere Message Broker V6.0 are different from those for WebSphere Business Integration Message Broker V5.0. Before you begin the migration you must review the system requirements, as outlined on the following Web site, and install any necessary prerequisites: http://www.ibm.com/support/docview.wss?rs=849&uid=swg27006594 Also, you must check the Preventive Service Planning (PSP) that is referred to in the Program Directory of the product that is installed. Chapter 25. Migrating the z/OS broker 463