Migrating and coexisting

Migrating involves collecting the configuration information from a previous release of a WebSphere Application Server product and merging it into a configuration for a new release. Coexisting involves running a new release of a WebSphere Application Server product on the same machine at the same time as you run an earlier release or running two installations of the same release of a WebSphere Application Server product on the same machine at the same time.

Before you begin

See Overview of migration, coexistence, and interoperability and Premigration considerations. For a compilation of links to documents and resources to help you plan and perform your migration, visit Knowledge Collection: Migration planning for WebSphere Application Server.

The migration tools basically save the existing WebSphere configurations and user applications in a backup directory and then process the contents of this backup directory to migrate the configurations and your applications from previous WebSphere Application Server releases to the latest release.

If you have a previous version of WebSphere Application Server, you must decide whether to migrate the configuration and applications of the previous version to the new version. Migration does not uninstall the previous version. The earlier release is still functional. If you run the earlier release at the same time as the WebSphere Application Server Version 6.1 installation, the two versions are coexisting.

To support coexistence, you need to provide non-default port assignments during profile creation. Note that for migration scenarios involving the possibility of rolling back to the previous version, you can choose to have the same port definitions and run either one version or the other.

For help in troubleshooting problems when migrating, see Troubleshooting migration.

About this task

For information on migrating to Version 6.1, see Migrating product configurations. For more information on coexistence among releases, see Coexistence support.

Procedure

  1. Prepare to migrate or update product prerequisites and corequisites to supported versions.

    Refer to the IBM WebSphere Application Server supported hardware, software, and APIs site for current requirements.

  2. Install the WebSphere Application Server Version 6.1 product.
  3. Migrate your WebSphere Application Server Version 5.x or Version 6.0.x product configuration to Version 6.1.
    You have the choice between migrating your configuration automatically using the migration tools or manually.
    • Use the migration tools to automatically migrate your configuration.

      See Using the migration tools to migrate product configurations.

      Consider the following points related to using the migration tools to automatically migrate your configuration:
      • Advantages
        • You copy the old configuration automatically.

          This includes all resource definitions, virtual host definitions, security settings, and so forth.

        • You recreate the same exact Version 5.x or 6.0.x configuration in Version 6.1, including the server definitions and deployed applications by default.
        • You can enable support for script compatibility.

          See WASPostUpgrade command.

      • Consideration

        This approach will copy the configuration exactly. A different approach, such as the manual approach, is required if your existing configuration is different from that which you want for the new configuration.

    • Manually migrate your configuration.
      Migrating your configuration manually involves the following activities:
      • You start with a clean slate and build up a new environment for Version 6.1.
      • Ideally, you would use an existing set of administration scripts to set up the complete Version 6.1 environment.
      • You move your applications to Version 6.1 as they are tested on Version 6.1.
      Consider the following points related to manually migrating your configuration:
      • Advantages
        • You can reuse the scripts for maintenance, replication, and disaster recovery.
        • You can easily refactor the topology if you desire.
      • Considerations
        • A complete set of administration scripts is a significant investment.
        • You must address script incompatibilities and changes before you migrate.
  4. Migrate Web server plug-ins as described in Migrating Web server configurations.
  5. Set up multiple versions of WebSphere Application Server to coexist.

    No runtime conflicts can exist for multiple instances and versions of WebSphere Application Server to run at the same time on the same machine. Potential conflicts can occur with your port assignments. See Port number settings in WebSphere Application Server versions for more information.

    1. Run Version 5.x or 6.0.x and Version 6.1 together as described in Setting up Version 5.x or 6.0.x and Version 6.1 coexistence.
    2. Run two concurrent Version 6.1 profiles as described in Setting up Version 6.1 coexistence.
    3. Create more than one Version 6.1 profile on the same machine.



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