WebLogic Server has migratable servers to make JMS and the JTA transaction system highly available.
A cluster provides high availability and failover by duplicating an object or service on redundant Managed Servers in the cluster. However, some services, such as JMS servers and JTA transaction recovery service, are designed with the assumption that there is only one active instance of the service in a cluster at any given time. These types of services are known as pinned services because they remain active on only one server at a time.
Most services deploy homogeneously on all Managed Servers in a cluster. With this setup, they can failover transparently from one Managed Server to another. However, pinned services target one Managed Server in a cluster. For pinned services, WebLogic Server supports failure recovery with migration instead of failover.
Migratable servers provide for both automatic and manual migration at the server-level, rather than the service level.
When a migratable server is unavailable for any reason (for example, if it hangs, loses network connectivity, or its host system fails), migration is automatic. Upon failure, a migratable server automatically restarts on the same system if possible. If a migratable server can't restart on the system it failed on, it migrates to another system. Also, you can manually start migration of a server instance.
See Whole Server Migration in Oracle Fusion Middleware Administering Clusters for Oracle WebLogic Server to prepare for automatic whole server migration, configure automatic whole server migration, and server migration processes and communications.
See Service Details in Oracle Fusion Middleware Administering Clusters for Oracle WebLogic Server for details on service migration mechanisms.
See JMS and JTA High Availability for details on JMS and JTA services.
If you configure Managed Server failover and one server in a cluster fails, whole server migration restarts a Managed Server on another machine.
Your system must meet specific requirements before you configure automatic whole server migration. See Preparing for Automatic Whole Server Migration in Administering Clusters for Oracle WLS.
To configure whole server migration, follow steps in Configuring Whole Server Migration in Administering Clusters for Oracle WebLogic Server.
See these topics for more information on configuring whole server migration: