This section describes whole server migration and how to configure it for Managed Server failover. When whole server migration occurs, a server instance migrates to a different physical machine upon failure. You must configure whole server migration if your environment uses special (pinned) services such as JMS and JTA.
This section includes the following topics:
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 running 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, enabling transparent failover from one Managed Server to another. However, pinned services target individual server instances in a cluster. For pinned services, WebLogic Server supports failure recovery with migration instead of failover.
WebLogic Server provides a feature for making JMS and the JTA transaction system highly available: migratable servers. 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 the migratable server cannot 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 Chapter 7, "JMS and JTA High Availability" for details on JMS and JTA services.
This section describes high level steps to configure a cluster for failover using whole server migration. If one server in the cluster fails, whole server migration restarts it 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 the steps in "Configuring Whole Server Migration" in Administering Clusters for Oracle WebLogic Server.
See these topics for more information on configuring whole server migration: