Application migration with the previous database
Application migration with the previous database uses a parallel target production environment that is configured differently from the source production environment. You use the existing product databases and upgrade the databases to work with the new environment.
You redeploy the applications from the source environment into the target environment.
When to use application migration with the previous database
When you use application migration with the previous database, you use the existing product databases and upgrade the databases to work with the new environment. You can maintain the history of applications installed in previous versions and carry over instances from previous versions.
Application migration with the previous database is supported for migration from the following products:
- IBM BPM Standard V7.5 or V7.5.1
- WebSphere Lombardi Edition V7.x
Use the application migration method with the previous database in the following scenarios:
- You want to move your applications to the new version without a dependency on the authoring tools and the development environment.
- You have long-running business process definition (BPD) processes or human task instances that started in the source environment and need to complete in the target environment.
- You can tolerate a production environment downtime window to perform the migration.
Benefits
Application migration with the previous database provides the following benefits:
- No dependency on the development tools
- Source environment applications are migrated to the target environment
- Source environment application data is moved, using existing database tables
- Business process definition processes and human tasks can start in the source environment and complete in the target environment
- Additional hardware and software resources not required to manage another production environment
Costs
Application migration with the previous database incurs the following costs:
- Downtime is required when the target product environment assumes the role of the source production environment
- Requires all applications on the source to be ready to migrate at the same time
- New features are not enabled automatically and sometimes unavailable without migrating the application artifacts using artifact migration
- Parallel production environment cannot be set up
- Test focus:
- End-to-end testing to validate migration process
- Regression testing and performance tuning
Risks
Application migration with the previous database involves the following risks:
- All previous version databases should be backed up to handle a possible database upgrade failure. In case of failures, the backup can be restored and the previous version can be started.
- Existing user applications should continue to run in the new runtime environment at the same level of function they had in the previous runtime environment. In some cases, however, there might be a change in code on which the application depends, such as a JDK change, which might have a negative impact on the unchanged application.
High-level tasks
Application migration with the previous database includes the following high-level tasks:
- Install the new product version.
- Back up all production databases.
- Create a new environment on the target installation and use the previous version product database during configuration.
- Upgrade the previous version product databases.
- Apply customizations or special configurations from the source version on the target environment.