Migration Terminology Oracle Fusion Middleware Online Documentation Library

7-2 Using Clusters for Oracle WebLogic Server migrated to another machine. In addition, an administrator can manually initiate migration of a server instance.

7.2 Migration Terminology

The following terms apply to server and service migration: ■ Migratable server—a clustered server instance that migrates in its entirety, along with all the services it hosts. Migratable servers are intended to host pinned services, such as JMS servers and the JTA transaction recovery servers, but they can also host clusterable services. All services that run on a migratable server are highly available. ■ Whole server migration— a WebLogic Server instance to be migrated to a different physical machine upon failure, either manually or automatically. ■ Service migration: – Manual Service Migration—the manual migration of pinned JTA and JMS-related services for example, JMS server, SAF agent, path service, and custom store after the host server instance fails. See Chapter 8, Service Migration. – Automatic Service Migration—JMS-related services, singleton services, and the JTA Transaction Recovery Service can be configured to automatically migrate to another member server when a member server fails or is restarted. See Chapter 8, Service Migration. ■ Cluster leader—one server instance in a cluster, elected by a majority of the servers, that is responsible for maintaining the leasing information. See Section 7.3.5, Non-database Consensus Leasing. ■ Cluster master—one server instance in a cluster that contains migratable servers acts as the cluster master and orchestrates the process of automatic server migration, in the event of failure. Any Managed Server in a cluster can serve as the cluster master, whether it hosts pinned services or not. See Section 7.4.4.7, Cluster Master Role in Whole Server Migration. ■ Singleton master—a lightweight singleton service that monitors other services that can be migrated automatically. The server that currently hosts the singleton master is responsible for starting and stopping the migration tasks associated with each migratable service. See Section 8.8.1.1, Singleton Master. ■ Candidate machines—a user-defined list of machines within a cluster that can be a potential target for migration. ■ Target machines—a set of machines that are designated as allowable or preferred hosts for migratable servers. ■ Node Manager—a WebLogic Server utility used by the Administration Server or a standalone Node Manager client, to start and stop migratable servers, and is invoked by the cluster master to shut down and restart migratable servers, as necessary. For background information about Node Manager and how it fits into a WebLogic Server environment, see General Node Manager Configuration in Node Manager Administrators Guide for Oracle WebLogic Server. ■ Lease table—a database table in which migratable servers persist their state, and which the cluster master monitors to verify the health and liveness of migratable servers. For more information on leasing, see Section 7.3, Leasing. Whole Server Migration 7-3 ■ Administration Server—used to configure migratable servers and target machines, to obtain the run-time state of migratable servers, and to orchestrate the manual migration process. ■ Floating IP address—an IP address that follows a server from one physical machine to another after migration.

7.3 Leasing