Oracle EnterpriseManager (OEM) is a tool supplied by Oracle that provides aneasy-to-use, graphical approach to managing one or more databases. Itcombines a number of distinct facilities into an integrated platformfor managing Oracle products. From the Oracle EnterpriseManager's console, the DBA may be able to:
Schedule jobs on multiple nodes at varying times
Monitor objects and events throughout the Oracle network
Customize the display using graphic maps and groups of network objects such as nodes and databases
Administer Oracle parallel servers
Integrate participating Oracle or third-party tools
The client/server architecture of Oracle Enterprise Manager consistsof a centralized console, common services, and intelligent agentsrunning on the managed nodes. Various applications reside on top ofthe common services, performing system management tasks.
The Oracle Enterprise Manager Console is a graphical user interfacethat provides menus, toolbars, launch palettes, and the framework toallow access to Oracle tools, plus utilities available through othervendors. The windows provide access to several components:
Discovers and displays a tree list of all the objects in a network,such as user-defined groups, nodes, listeners, name servers, anddatabases, plus the objects they contain.
Provides a means to create, save, modify, and recall views of thenetwork. Objects can be dragged and dropped from the Navigator intothe Map view to create groups to be monitored.
Provides access to the Navigator, Map, Job, Event, and databaseadministration applications.
Oracle Enterprise Manager has a set of common services that helpmanage nodes throughout the Oracle network. Key to these services isthe repository. The Oracle Enterprise Manager repositoryis a set of tables in an Oracle database. Each administrator isassociated with a specific repository in a database, and anyinformation related to the tasks performed by the administrator isstored in that repository. The repository provides a centralizedlocation for storing information on configurations, jobs and events,historical collections, tuning recommendations, the preferredcredentials for each user, and other information associated with theDBA user. The repository tables can be installed in any databaseaccessible in the Oracle network, and a DBA can log on to therepository database from any machine.
The Job Scheduling System allows themanagement of job scheduling among the databases, listeners, andnodes being administered. Jobs can be scheduled and run on remotesites throughout the network at various times, such as daily orweekly, and at single or multiple destinations.
The Event Management System allows trackingand display of the status of events occurring on the databases,listeners, and nodes in the Oracle network. A job can be specifiedthat will take corrective action when a particular event is detected.
Oracle Enterprise Manager uses intelligent agents and a communicationdaemon to manage Console tasks such as scheduling and running remotejobs and monitoring events on remote sites. The intelligent agent isa process that runs on remote nodes in the network and functions asthe executor of jobs and events sent by the Console via thecommunication daemon. The agent can function regardless of the statusof the Console or network connections.
Access to Oracle services on the network is controlled by a set ofuser-defined, preferred credentials for the available nodes andservices. Oracle Enterprise Manager encrypts the user authenticationinformation in the repository and provides it as part of theconnection request from the Console or Console-launched applications.
Oracle Enterprise Manager includes a set of standard integrateddatabase administration applications. These applications arespecialized management tools that can be launched directly from theConsole or the Administration toolbar. Third parties can writeapplications that integrate into the Console and use the availablecommon services, and these applications can be launched directly fromthe Console.
A command-line interface is sometimes necessary or desirable, soOracle Server Manager provides a conversational line mode. In linemode, DBA commands can be explicitly executed on a commandline.