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Oracle9i: Repository, Oracle Management Server und Enterprise Manager Konsole

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Überblick Architektur

Der Oracle Enterprise Manager basiert auf einer dreischichtigen Architektur (Three-Tier): Die Enterprise Management Konsole als first tier, der Management Server mit seinem Repository im middle tier und die verwalteten Zielsysteme wie Knoten/Datenbanken sind im third tier. Das heißt, dass Konsole, Management Server, Repository und Datenbanken auf derselben oder unterschiedlichen Maschinen installiert sein können, je nach Bedarf. Wie es im eigene Untermnehmen am Besten ist, hängt von vielen Faktoren ab, z.B. Workload, Load balancing, Rollen und Rechteverteilung zwischen Administratoren, Firewalls oder VLAN-Architektur.


(aus: Oracle Enterprise Manager Concepts Guide)

Die Konsole des Enterprise Managers hilft Usern und Administratoren, Verwaltungsaufgaben einer Datenbank über ein grafischen Interface zu erledigen.
Die Konsole sitzt - abgesehen vom Standalone-Modus - auf einem Oracle Management Server (OMS) auf und interagiert nicht direkt mit den verwalteten Knoten.

Der OMS bekommt als Eingabemn aus der Konsole und schickt sie zu dem Intelliegent Agent. der auf dem betroffenen Knoten läuft. Ein OMS istsklaierbar, das heißt: Wenn seine Workload zu groß wird, kann man weitere OMS auf zusätzlichen Maschinen einrichten. Pro Maschine kann es jedoch immer nur einen OMS gebe. Der OMS benutzt für seine Metadaten ein sogenanntes Repository, ein Satz Tabellen, wo alle Informationen von Konsolen und Knoten abgelegt werden.
Ein Repository wird mit dem Enterprise Manager Configuration Assistant (EMCA) erzeugt.

Der third tier umfasst Datenbanken, Knoten und andere Services. Auf einem verwalteten Knoten sitzt ein Intelligent Agent, und zwar nur einer pro Maschine. Der Agent ist weder von einer betsimmten Datenbank, noch von einem betsimmten OMS abhängig, sondern arbeitet unabhängig. Das heißt, der Agent könnte laufen, obwohl die Datennbank abgestürzt ist. Ein OMS sendet dem Intelligent Agent seine Aufgaben, und dieser führt dann diese Jobs und Ereignisse auf dem Knoten aus und gibt dem OMS Feedback. Der OMS wiederum macht eine Update der Metainformationen im Repsitory und schickt Informationen zurück zu den angeschlossenen Konsolen.


 
Starten und Stoppen der Dienste

On Windows launch EMCA from the Start menu. On Unix, enter emca from the prompt to launch EMCA. The EMCA wizard guides you through the configuration of a repository. You can use an existing tablespace to hold the repository or create a new tablespace. Having a separate tablespace to hold the repository helps administering managed databases effectively. Do not use SYSTEM as the tablespace for the repository.

Once the repository is created, start OMS. On Windows start and stop the OMS from the Services panel. On Unix, the following commands control OMS.

There can only be one management server per machine. If the workload increases, install Management Server components on additional machines and configure them as per the steps above.

Troubleshooting OMS
What if you are unable to start OMS. Setup a Trace file by setting parameters in omsconfig.properties file. This file is located at $ORACLE_HOME/sysman/config directory. The following are the minimum parameters that need to be set.

TRACING.ENABLED=TRUE

LOGGING.ENABLED=TRUE

TRACING.LEVEL=2

After setting the above parameters, start OMS again. If it fails to start check the log files located at $ORACLE_HOME/sysman/log. This log file states the cause of the error. Rectify the error and start OMS again.

 

On Windows, generally, the various Enterprise Manager tools are launched from the Start menu. On UNIX, the tools are launched from the line prompt. The page below outlines the various commands applicable to 2.x and 9.x versions on Unix.

 Launch Tools Release 2.x Release 9.x
Enterprise Manager Configuration Assistant emca emca
OMS oemctrl start oms oemctl start oms
oemctrl stop oms oemctl stop oms
oemctrl status oms oemctl status oms
Intelligent Agent lsnrctl dbsnmp_start agentctl start agent
lsnrctl dbsnp_stop agentctl stop agent
Listener lsnrctl start lsnrctl start
lsnrctl stop lsnrctl stop
Console oemapp console oemapp console
DBA Studio oemapp dbastudio NA
Blackout using Command-Line NA agentctl utility

Before the release of v2.1 Enterprise Manager, the DBA Management Pack tools such as Instance Manager, Schema Manager, Security Manager etc. had to be launched as an individual application. Of course, they can be launched from the Console as well if a repository had been configured. This means that if you have to work between different applications without the use of the Console, you had to launch the individual applications to work on them. This was not a very convenient method particularly if you had to switch between different applications frequently. 

The concept of DBA Studio was introduced from Enterprise Manager v2.1. DBA Studio is a tool that provides a centralized location from which the other applications such as Instance Manager, Schema Manager, Storage Manager etc were launched. This provided ease of using the various applications from a single launch pad. The DBA Studio also provided a Master-Detail view of various tasks. This means if you select a task on the Navigator tree, it is displayed on the right-side of the DBA Studio. The Console before Release9.x had no Master-Detail functionality.

Console

A brief background on the Console functionality will be of help. Prior to Enterprise Manager Release 9.x, the Console can be launched only through the Oracle Management Server (OMS). This means a repository must have been configured and the OMS setup. There was no method of logging on to the Console without the OMS. The pre 9.x Console had no Master-Detail functionality as was found in the DBA Studio.

However, from Oracle Enterprise Manager Release9.x, the Console has undergone significant improvements. One of which is the ability to log on to the Console in standalone mode. The Console in standalone mode does not use the OMS. This is suitable for a single administrator performing operations locally. Moreover, the Console was enhanced to provide a Master-Detail view. All the functionality found in the DBA Studio was integrated into the Console 9.x. This led to redundancy of the DBA Studio and hence this functionality is no longer available from Release 9.x


The Console in Oracle9i Enterprise Manager has several new features. The look and feel of the Console has changed and the functionality has improved significantly. Gone are the familiar panes or windows representing Jobs, Events, and Groups found in v2.x. In its place is a neat layout which brings the master detail view. An overview of the new features are briefly explained in the following section.

Standalone Mode
The Console can be launched either in Standalone mode (without connecting to OMS) or through OMS.

Standalone Repository
Standalone Repository is new to Oracle9i Enterprise Manager. This permits applications such as Change Manager, Oracle Expert to work in standalone mode with the help of a standalone repository.

Master Detail View
This functionality is similar to the master-detail view found in earlier release of DBA Studio. When you select an item in the navigator tree, the properties are displayed in the right side of the Console. The Console integrates the functionality of DBA Studio. Hence, DBA Studio has become redundant and is no longer available with Enterprise Manager Release9i.

Discovery of Nodes
Discovering database, nodes, and other services can only be done by Super Administrators. Regular Administrators cannot discover or remove services.

Customizable Console
This feature enables Super Administrators to assign services to Regular Administrators. For example, company 'ABC' has two instances PROD and U01. Regular Administrator 'Bob' is responsible for some services/targets in instance PROD. Bob can now be assigned only those services and targets on PROD that he is responsible for. Other targets and services are not displayed for Bob. Services can be assigned either during Discovery stage or through Manage Administrators function.

Reconnect to OMS
If the Management Server goes down, you can reconnect to OMS from the Console. A dialog box prompts you to reconnect to the Management Server. This is possible if you have more than OMS and one fails. The failed Management Server can then be restarted from the Start menu or command line.

Management Regions
This feature enables assigning Nodes in a repository to different Management Servers. For example, A and B are the available Management Servers and Node1 and Node 2 are the available nodes. Using Management Regions, Node 1 can be assigned to Management Server A and Node 1 can be assigned to Management Server B. This is particularly useful for geographically dispersed systems within a network or for large deployments.

Support for Oracle9i Features
Oracle9i Server has several new features such as Persistent parameter file, Undo Tablespace support, Buffer Cache Advice, Temporary Tablespace. Oracle9i Enterprise Manager supports these new features


This feature is new to Release 9.x. From Release 9.x, Regular Administrators have to be granted specific access to Targets they will be managing. Only Super Administrators can grant specific access to Targets to the Regular Administrators. Hence, depending on the Regular Administrator's functions, they may be granted access to all or some of the Targets. The Console Navigator will display or hide the Targets accordingly. This article explains this concept briefly and illustrates the method of doing it. The term Regular Administrator refers to an Administrator who is not a Super Administrator.

The pre-Oracle9.x Console displayed all targets such as Jobs, Events, Databases, Nodes etc. to all the Administrators. This resulted in all targets being displayed to all the Administrators though they may be managing only some of them. This was not the desired option, particularly from security considerations. This has changed from Release 9.x Enterprise Manager. Regular Administrators have to be granted specific access to targets they will be managing. This right can only be granted by a Super Administrator. If an Administrator has been granted access to a specific target he/she can access only that target. The other targets are not displayed. Consider the following example:
Administrator Tom is responsible for running some SQL scripts on database u01 through the 'Jobs' functionality. Administrator John Doe is responsible for managing tablespaces on database u02 through the 'Events' functionality. The Super Administrator can now specify that Administrator Tom has access only to the Job system on database u01. Similarly, he can specify that Administrator John Doe access only to the Event system on database u02. When Administrator Tom logs on to the Console he can access all the Job functionality on the specified database. He will not be able to view the Events functionality in the same database nor will be able to view and access other targets such as Listeners, HTTP Servers etc. Following are the steps involved in granting access to Regular Administrators.

  • Log-on to the Console as a Super Administrator. 
  • Select Configuration -> Manage Administrators from the menu. 
  • Click the Add button. Enter the name of the Administrator and the password. 
  • Check boxes to specify access to jobs system, event system, or both.
  •  Select Grant Access to Targets to grant specific access to databases, nodes, listeners etc.

This article assumes you have Enterprise Manager web server components installed and you are running the standard Oracle HTTP Server.

 

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Petra Haberer  Version 0.0.6