Oracle Enterprise Manager (OEM)

Oracle Enterprise Manager is Oracle's GUI-based database management tool. It is possible to manage the oracle environment using SQL and PL/SQL but OEM gives you a console based framework to help you with almost all of your day-to-day management activities, including tasks such as backup, recovery, export, import and data loading, it also makes it easier to use the oracle advisors.

There are two version of OEM - a single instance version called Database Control and a system wide version that lets you manage all your systems called Grid Control. Most dba's do not like using GUI's but it makes sense to use the GUI for the easier day-to-day administration tasks like adding users, resizing tablespaces, etc, I think that knowing both SQL and PL/SQL and the GUI will make you a better dba in the long run.

The benefits of using the OEM

Out-of-the-box Management Installing and configuration of the OEM (both database and grid control) is a breeze, if using the DBCA to install Oracle it will automatically be installed for you, configuring the OEM is a trivial task.
Web-based Management OEM can be configured to use both HTTP or HTTPS, so security can be tightened if required. Being web based all you need is web browser to access the OEM.
Real-Time Monitoring Normally you have to write scripts or use a 3rd party tool to perform real-time monitoring, which can cause additional expensive or time, OEM will perform real-time monitoring right from the off. The new hang analysis feature in 10.2 helps during a database hang, when SQL scripts can't get information back to you quickly, by attaching directly to the SGA bypasses SQL and helps you out when normal SQL is used.
Complete Environment Monitoring

A poor performing database could be the result of a problem anywhere in the application stack (web server, app server, etc). OEM can monitor the performance of all the components in the stack not just the Oracle database. It can monitor

  • The entire Platform
  • End user experience
  • Systems and web applications availability
  • The extended network components
  • Business transactions
  • Historical data analysis and change tracking
Application Performance Monitoring

Oracle uses alert and notification systems to monitor the database, these alerts can identify problems quickly thus using a pro-active approach, thresholds can also be easily adjusted with the OEM. It can identify

  • Monitors the performance and availability of the system
  • Indicates outages and bottlenecks throughout the application system
  • Analyzes the root cause of performance with drill-downs
  • Minimizes application downtime through the use of efficient problem-resolution tools.
Scaleable Management Capability OEM is highly scalable, the only requirement is that any new servers require the management agent started.
Consolidated Database Management The home page of OEM will contain everything you need for a quick overview of your environment, this means that any problems can be identified very quick, a few more clicks and you have advanced performance charts available.
Integrated System Management OEM uses the Smart Plug-In (SPI) to provide integration in system-wide monitoring tools such as HP Openview.

OEM Database Control

You can automatically install OEM with installing Oracle via the DBCA, just select the use database control for database management option.

Manually configure OEM

unix: export ORACLE_SID=D01
windows: set ORACLE_SID=D01

emca -config dbcontrol db

Start dbconsole emctl start dbconsole
Stop dbconsole emctl stop dbconsole
dbconsole status emctl status dbconsole
Start management agent emctl start agent
Stop management agent emctl stop agent
Management agent status emctl status agent

Main OEM Page

The main OEM page is displayed below, please refer to the oracle web site on how to navigate and what is available on the OEM.

OEM Grid Control

OEM Grid Control can manage a number of systems across the environment, this means easier management. The Grid Control has a number of components

Note that the grid control product is a licensed product which you can obtain from Oracle.

If possible it is best to install the Grid Control on a server on its own, depending on the number of servers you wish to monitor will determine the performance and disk space required for the server.

There are a number of commands that can be used to control the Oracle Management Services (OMS)

Status # emctl status oms
Start # emctl start oms
Stop # emctl stop oms

To install Grid Control follow below

Grid Control Installation
  1. Make sure that the Oracle CD is in the CD Drive and run the following

  2. At the Welcome screen click Next
  3. Accept the default Operating System group Name, click Next
  4. You now need to run a script called as user root in another terminal session.

    # cd $ORACLE_BASED/oraInventory
    # ./
  5. Now click continue back in the Installer window
  6. Now choose the directory for the OEM files and click Next
  7. If using a new server select the option that creates a new Oracle database, click Next
  8. It will now perform prerequisite check, click Next
  9. Choose a password for SYSMAN and click Next
  10. Select password for SYS, SYSTEM AND DBSMNP, click next
  11. You can alter the Metalink and Proxy information if so desired, click Next
  12. Choose the SID and the Global database name for the database, click next
  13. Specify the location for all the database files, click Next
  14. Review the components and then click Next
  15. You will now watch while Grid Control is installed, you will be asked to run as user root
  16. A window will be displayed showing the various configuratrion assistants, click OK
  17. yet again run the script as user root, then click Next
  18. This screen is important as it details all port numbers and links to the web page (make note)
  19. Click Exit to end the installation

To install the OEM Management agent only

Management agent Installation   1-7. Use the proceeding first seven steps
  1. In the select a product window, choose the additional management agent installation type and click Next
  2. specify the hostname and click Next
  3. Click Next after reading the security page
  4. Review the summary and click Next to start the install
  5. Click Exit to finish the install
  6. In Grid Control click on the target tab, you see all the discovered hosts