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CHAPTER 9

Oracle Enterprise Manager

In this chapter

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Understanding the Enterprise Manager Architecture

Enterprise Manager is much more than just a set of database administration tools. This product provides a framework for an enterprise-wide distributed system management solution. For example, a database administrator can physically reside in Los Angeles and manage databases in New York, London, and Tokyo from the same integrated console. A set of centrally located Oracle tables forms a repository to store information necessary to support the activities of each administrator. This repository may reside anywhere on the network or on the local Windows 95 or Windows NT workstation supporting the Enterprise Manager client.

Enterprise Manager is open and extendible. Tool Command Language (Tcl), pronounced "tickle," is a nonproprietary and widely used scripting language characterized by ease of use and extensibility. Tcl is used to submit commands to remote operating systems and databases for execution. The implementation of Tcl used by Enterprise Manager, known as OraTcl, includes extensions that enable functions you need to fully manage an Oracle database environment:

NOTE
To become familiar with Tcl, review the Enterprise Manager Tcl scripts found in <ORACLE_HOME>\SYSMAN\SCRIPTS\TCL.

SNMP is an open standard used by remote intelligent agents to communicate with non-Oracle software and hardware. Originally, SNMP was designed to communicate with network devices, but it is now used to communicate with applications as well. Use of the SNMP standard enables integration of a variety of third-party software and hardware with Enterprise Manager. Application developers integrate applications within the console using Object Linking and Embedding (OLE) or calls to one of the published Application Program Interfaces (APIs) specific to Enterprise Manager. To top it off, when information moves over the network between the console and the remote intelligent agents, it can be secured with Oracle Secure Network Services using the Net8 Advanced Networking Option (ANO). This level of security makes it possible to administer remote databases over the Internet.

All of these components and technologies are tied together with an architecture that makes use of a graphics-oriented console client linked to remote intelligent agents that communicate with the databases (see Figure 9.1). In addition to the messages between the communication daemon and the intelligent agents, the application components such as the Database Administration Tools communicate directly with remote databases by using SQL over Net8. Tasks performed by the application components directly on remote databases in real time do not use the

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communications daemon. The communications daemon uses either native TCP/IP or Net8 Transparent Network Substrate (TNS) connections to communicate with remote intelligent agents to perform core console functions such as job scheduling and event management.

FIG. 9.1
The Enterprise Manager
architecture provides
centralized database
management.

The discovery cache is a large buffer that is used to store metadata describing the services and nodes managed by the console. Metadata is collected the first time an object is accessed, and the data is stored in the discovery cache for the remainder of the session. When metadata in the discovery cache is accessed, there is no need to repeat queries to determine the structure of remote databases. As a result, response time improves and unnecessary resource utilization is avoided. At the end of a session, the data is stored in the repository so that it will be available for the next session. Custom applications can also access the discovery cache.

The intelligent agents autonomously execute and manage remote activities. After the communications daemon instructs a remote agent to execute a particular script at a given time, the script executes independently from the console. If the console is unavailable when it is time for a remote job to run, the agent manages the execution and buffers up to 500 returned messages. The agent passes this information back to the console when it becomes available and reestablishes communication. Similarly, intelligent agents handle remote event monitoring and responses independent of the console.

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Most installations of Enterprise Manager do not take full advantage of the architecture. In some ways, this is a tribute to the flexibility of the product to support real-time database administration using components such as Schema Manager without depending on the entire architecture. Sites that already use robust third-party systems management tools such as BMC Patrol, CA-Unicenter, Compuware EcoTools, or Platinum ProVision duplicate existing functions while increasing administrative overhead and system workload if the entire framework is implemented. Sites that are not using such tools might find Enterprise Manager, which is bundled with Oracle8 Server at no extra cost, a suitable substitute (value-added products such as the Performance Pack are available at an additional charge).

Due to the limited scope of Enterprise Manager and currently available add-on tools to extend its capabilities, it is not a substitute for a robust systems management product whose scope extends well beyond database management. Particularly in large enterprises where the operations staff benefits from the efficiencies of a common user interface and approach to tasks across many platforms, database technologies, and other managed technology, a more comprehensive solution might add value. In any case, it is likely that there is a place for at least some of the components of Enterprise Manager in any Oracle database environment.

Getting Started

Enterprise Manager has a robust architecture, but it is easy to start using it. After the software is installed, tools such as Schema Manager, which does not require a repository or remote intelligent agent, are immediately functional. The repository enables some functions such as data accumulation for performance analysis and capacity planning. This repository makes some activities easier, such as logging into the console, by storing preferred credentials between sessions. Because stored information varies from one administrator to the next, each administrator should have a separate repository. Only one instantiation of Enterprise Manager can connect to a repository at any given time.

The best place to start exploring and gain immediate benefit from Enterprise Manager is using the following Database Administration Tools:

These five tools can be accessed in five ways. The first is directly from the Windows task bar. For example, from the Start menu on the task bar, choose Programs, Oracle Enterprise Manager, Instance Manager to start the Instance Manager. Second, the default configuration of the

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