An Overview of Migrating to WAS 5.0 for iSeries
WebSphere* Application Server (WAS) migration involves transferring existing configurations and applications from an older WAS release to a newer WAS release. On the surface, this can appear to be a daunting task. Fortunately, WAS ships with a set of tools and provides documentation to assist with migration.
This article provides an overview of WAS migration with a focus on migrating to WAS 5.0 (Base) and Network Deployment (ND) editions; however, much of this information also applies when migrating to WAS 5.0-Express. Several additional articles are planned that will present more detailed information on the supported migration paths.
WAS migration allows you to transfer existing configuration settings and applications to WAS 5.0 from previous versions (e.g., WAS 3.5 or WAS 4.0). Table 1 outlines supported WAS releases for iSeries. Existing configuration settings and components are applied to the new environment during the migration process.
WAS migration is performed using two tools that are shipped with each WAS version: WASPreUpgrade and WASPostUpgrade. These tools migrate WAS runtime configuration data such as ports, JVM settings, WAS security configurations, data source configurations, etc., and application components such as Java ServerPage* (JSP) components, servlets and Enterprise JavaBean* (EJB) components. Alternatively, you can manually configure all required resources and manually install all applications in the new WAS version. Application components may have to be modified to run in the new environment due to changes in the supported Java* 2 Platform Enterprise Edition (J2EE) specifications and APIs.
Migration can be performed from WAS version to WAS version. For example, WAS 3.5 or 4.0 instances can be migrated to WAS 5.0. Additionally, migration can be performed from WAS edition to WAS edition. For example, WAS 3.5 Standard Edition (SE) can be migrated to WAS 4.0 Advanced Edition (AE). For details, see Table 2 .
The process for migrating to a new WAS version is as follows:
- Plan for the migration.
- Migrate applications. Ensure that each application conforms to the specifications supported by the new WAS version.
- Migrate WAS instances. Use the WASPreUpgrade and WASPostUpgrade to migrate configuration data and applications to the new WAS version.
- Complete the migration. Some manual configuration may be required after the migration.
These steps are covered in more detail in later sections.
Multiple WAS versions and editions can coexist on the same iSeries server, and new versions can be installed without impacting existing WAS environments.
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