When whole server migration occurs, the server instance migrates to a different physical machine upon failure.
For detailed information on whole server migration, the topic "Whole Server Migration" in the guide Administering Clusters for Oracle WebLogic Server.
This chapter 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 the 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 referred to as pinned services because they remain active on only one server instance at a time.
In a cluster, most services deploy homogeneously on all Managed Server instances in the cluster, enabling transparent failover from one Managed Server to another. However, pinned services such as JMS and the JTA transaction recovery system are targeted at individual server instances within a cluster. For these 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 becomes 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. In addition, an administrator can manually initiate migration of a server instance.
See "Whole Server Migration" in Oracle Fusion Middleware Administering Clusters for Oracle WebLogic Server for more information on preparing for automatic whole server migration, configuring 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 6, "JMS and JTA High Availability" for more details on JMS and JTA services.
This section describes the 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.
Topics in this section include the following:
Your system must meet specific requirements before you configure automatic whole server migration. See Preparing for Automatic Whole Server Migration in the guide Administering Clusters for Oracle WLS.
Before configuring server migration, ensure that your environment meets the requirements outlined in Section 3.2.1, "Prerequisites for Configuring Automatic Whole Server Migration".
To configure whole server migration, follow the steps in "Configuring Whole Server Migration" in the guide Administering Clusters for Oracle WebLogic Server.
See the following topics for additional information on configuring whole server migration: