Oracle Enterprise Manager 12c Cloud Control – A Review

By 4th March 2016 October 25th, 2019 Uncategorized


About Oracle Enterprise Manager 12c

The architecture of the OEM for Grid Control has three distinct components:

– The collection agent (Oracle Management Agent or OMA)

– The aggregation agent (Oracle Management Server or OMS)

– The repository agent (Oracle Management Repository or OMR)

The OMA runs on the target host and collects information about hardware, OS, and services that run on the target. The OMS runs can be on single-node or multiple-nodes. The OMS collects the information from the OMAs into the repository. It also acts as the user-interface — by generating web-pages for database administrators to view the status of systems and services. The OMR is an instance of Oracle database that stores the data collected by the OMS.

Benefits of Oracle Enterprise Manager 12c

Enlisting all the benefits of Oracle Enterprise Manager 12c would go beyond the scope of this document and thus below are some of the major benefits of OEM 12c:

Database Patching & Updates: Manual patching I time consuming and sometimes confusing as well as error prone. OEM 12c addresses these by:

1) Use of Patch Plans: Multiple databases can be patched in just few steps:

– Patch description

– Select patches to be applied

– Deployment options

– Patch validation and analysis

– Review and deploy

2) Out of place patching support

3) Automated patching and integration with MOS

Real-time Database Operations Monitoring: Real-time monitoring of operations such as SQL statements :

– Simple Statements: SQL Monitoring, PL/SQL Monitoring

– Composite Database Operations

Configuring Oracle Active Data Guard using Oracle Enterprise: Oracle Data Guard can be configured and monitored with help of OEM in few steps.

Linux/Unix Host Monitoring: Oracle Enterprise Manager 12c captures host performance metrics in the repository and these details can be accessed from Cloud Control by selecting the Host target and selecting Monitoring CPU/Memory/Disk Details.  This displays a graphical view of the Host performance metrics.

Root Cause Analysis- Manual vs. Automation: Component targets that are up or those that have critical incidents are pinpointed easily and quickly thanks to the help of Oracle Enterprise Manager 12c’s Topology Viewer. Oracle Enterprise Manager 12c goes through all the components in the system one by one until it finds the root cause.

Managing Oracle Database 12c and Beyond: Oracle Enterprise Manager 12c has been able to monitor and manage Oracle Database 12c as soon as it was released; including new management support for Oracle Multi-tenant, a new Oracle Database 12c Enterprise Edition option. This new option embraces a multi-tenant architecture that lets you have many “sub databases” inside a single “super database.”

ASH Analytics:

– Multi-dimensional view of ASH data

– DB-time analysis

– Top Activity

Real-time Automatic Database Diagnostics Monitor:

– Compare database activity over two periods of time

– Real-time ADDM analyses hung or very slow databases

– Finds sources of contention



Objective (The need!)

Our client’s environment is very large and consists of broad variety of Oracle applications viz. Oracle EBS, Oracle SOA Suite, Oracle BI publisher, Oracle Discoverer etc. These applications have their own production and multiple test systems.

These systems are critical for business and needs to be available as close as possible to 100%. Apart from monitoring them, another crucial task is to manage various jobs that are needed to be executed against respective databases.

In such a complex environment, a centralized approach is needed to take responsibility of keeping an eye of every system, manage compliance and, in process, support Database Administrators to focus on solutions rather than identifying problems.

Oracle Enterprise Manager 12c Installation Overview

As seen in about section, OEM comprises of three main components viz. Management Server (OMS), Management Agent (OMA) and Management Repository (OMR).

Installation files of OMS are obtained from Oracle website. After OMS is installed, OMAs can be deployed on target servers that are to be monitored.

OMR, however is just an Oracle RDBMS database that is used by OMS to store configuration, metrics etc in tables created under %MGMT% schemas. Thus, an Oracle RDBMS installation software needs to be installed first and a blank database needs to be created for repository purpose.

Plan to be followed for installation is as below:

1) Installation of Oracle RDBMS 12c Software

2) Creation of blank/template database for repository

3) Installation of Oracle Enterprise Manager 12c, OEM 12c installer also installs:

– Oracle Fusion Middleware

– Oracle Weblogic Server

4) Deployment of Management Agents

– Monitoring user configuration

– Pulling/Pushing Agents to server

Value Additions

As explained in previous section, in this scenario Oracle Enterprise Manager 12c has played a highly crucial role as outlined below:

– Monitoring of Oracle EBS and components

– Monitoring of Fusion Middleware Applications (SOA, BI etc)

– Monitoring of Oracle Database and components (database instance, listener etc)

– Monitoring of Physical Standby Databases

– Monitoring of Key Database Schemas and Objects

– Monitoring of User Sessions

– Monitoring third-party hardware via OEM plugins

– Managing Patch Levels of Databases and Apps

– Managing Database Backups

– Managing Database Backup Catalog

– Managing and Scheduling Database Jobs via OEM Job Scheduler

– Managing Reports

– Managing compliance of Oracle Environment as per Oracle Standards

– Performance monitoring – SQL, real-time SQLs

– Performance monitoring – Database Jobs

– Performance monitoring – Database Instances

– Performance monitoring – Host Servers

– Performance analysis – AWR, ADDM, ASH reports

– Performance analysis – With help of graphical representation of monthly performance data

With ever growing demand of extensible in Oracle environment, Oracle Enterprise Manager has much more to be listed in value additions with upcoming time.

Time Requirement

Below is a representation of timing details for the implementation that was carried-out (excluding time required in downloading of installation files)

Sr # Activity Approximate Time
1 Installation of Oracle RDBMS Home 12c 2-3 Hours
2 Creation of Oracle 12c Database (for repository) 30 minutes to 1 Hour
3 Installation of Oracle Enterprise Manager 12c (FMW included) 3-4 Hours
4 One time configuration of Oracle Enterprise Manager 30 minutes to 1 Hour
5 Deployment of Oracle Management Agents 15-30 minutes per host
6 Setting up Monitoring on hosts
7 Setting up of Backup, Job Scheduler, Physical Standby etc 1-2 Hours


Since Oracle has everything well documented the implementation process was smooth and hassle free. Though there was a challenges faced from client’s security point of view described as below:

  • There was a security constraint in client’s policy with OEM installation user to be directly accessed via ssh. This under no circumstances could have been compromised
  • To ratify this issue, a new user was created with common installation group
  • Management Agents, as opposed to being deployed via Oracle Enterprise Manager, were pulled using Agent Pull script provided by OEM itself.


By the time this conclusion is being written, it has been a good time for us to scrutinize various features of OEM. The results have been more than satisfactory with high extensibility and features offered by Oracle Enterprise Manager in every domain.

We recommend using Oracle Enterprise Manager for any size of environment, as it provides a centralized approach to daily needs of a Database/System Administrator that is not only limited to monitoring and management of systems but goes far beyond.

Author : Anurag Tripathi 


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