Install Oracle Enterprise Manager 12C release 3( on OEL 5/6

This article presents installation of new Oracle Enterprise Manager 12C version on OEL5, OEL6.

Read following article to find out how to install OEL5,6 and database 11G Linux. They are required for this installation:

This installation was done on OEL6(extra library must be installed) but it’s no different on OEL5

Oracle Database 12C Relase1( is not yet supported for Cloud repository.

Software used:

  • Oracle Virtual Box – 64 bit
  • Oracle Enterprise Linux 6 – 64 bit
  • Oracle Database 11G Release 2( – 64 bit for Linux
  • Oracle Oracle Enterprise Manager 12C release 3( – 64 bit for Linux

Binaries Oracle Enterprise Manager 12C ( - enterprise software - enterprise software - enterprise software

You need at least 5GB of memory for this installation so check your VirtualBox settings before proceeding.

1. First step is to deinstall database control from current database as user oracle

emca -deconfig dbcontrol db -repos drop

you will be asked to enter database SID, port, sys and sysman password

[oracle@oel6 ~]$ emca -deconfig dbcontrol db -repos drop

STARTED EMCA at Jul 8, 2013 10:43:28 PM
EM Configuration Assistant, Version Production
Copyright (c) 2003, 2011, Oracle.  All rights reserved.

Enter the following information:
Database SID: ORA11G
Listener port number: 1521
Password for SYS user:  
Password for SYSMAN user:  

WARNING : While repository is dropped the database will 
          be put in quiesce mode.
Do you wish to continue? [yes(Y)/no(N)]: Y
Jul 8, 2013 10:44:24 PM oracle.sysman.emcp.EMConfig perform
INFO: Repository successfully dropped
Enterprise Manager configuration completed successfully
FINISHED EMCA at Jul 8, 2013 10:47:14 PM

2. Install extra software as root (only for OEL6). Rest you should have from OS installation. You can always download missing packages during installation.

yum install glibc-devel.i686

3. Make sure the shared memory filesystem is big enough for Automatic Memory Manager (3GB for database + 500M for other applications) to work. This part must be executed as root.

Add following line to “/etc/fstab” file

tmpfs /dev/shm tmpfs defaults,size=3584m 0 0

Resize /dev/shm size online

mount -o remount,size=3584M /dev/shm

4. Change initialization parameters for minimum database settings. Do all following commands as user oracle.

sqlplus / AS SYSDBA

alter system set processes=300              SCOPE=SPFILE;
alter system set memory_max_target=3G       SCOPE=SPFILE;
alter system set memory_target=3G           SCOPE=SPFILE;
alter system set shared_pool_size=300M      SCOPE=SPFILE;
alter system set session_cached_cursors=100 SCOPE=SPFILE;
alter system set sga_max_size=0G            SCOPE=SPFILE;
alter system set sga_target=0G              SCOPE=SPFILE;
alter system set pga_aggregate_target=0G    SCOPE=SPFILE;

--restart oracle instance.

5. Create directories for Enterprise Manager and Agent as user oracle

mkdir /ora01/app/oracle/em
mkdir /ora01/app/oracle/em_agent

6. Start installation as user oracle, remember to run command xhost+ as root.

xhost +
access control disabled, clients can connect from any host
mkdir install
unzip -d install
unzip -d install
unzip -d install
cd install

7.If you don’t want to get email after installation just uncheck “I wish to receive security updates via My Oracle Support” and click “Next” button


8. You should get following warning message just ignore it and click “Yes” button


9. Just check “Skip” option to ignore downloading latest patches and click “Next” button


10. You should see that prerequisite checks are started. If all is fine click “Next” button. If you see errors you need to correct them by reading installation logs.


11. I just select simple installation method and click “Next” button


12. You need to specify directory where you want to install Enterprise Manager software and host name. When it’s done click “Next” button.


13. On this page you need to specify Administration password.The password can be changed later for each components of EM12C. Additional you need to specify details about your database where repository of EM12C will be installed plus password for user SYS. Uncheck checkbox “Configure Oracle Software Library” – warning is displayed.  This option is used only when you are planing to install many OMS. When it’s done click “Next” button.



14. You can see such error so ignore it and click “Yes” button. Installer will fix it automatically.


15. In case you get following screen with warning you can ignore it or make appropriate suggestions. In my case my installation is very small so I can ignore it. Just click “OK” button to proceed.


16. You should see following screen with summary just before installation. You can read here some interesting informations like: space required by installation, installation directories etc. Just click “Install” button.


17. It can take a lot of time to install all required components. Just run some funny movie :), relax and wait.


18. As last step you need to run following script as user root. When the script is finished click “OK” button.


19. You should see installation report with details URL addresses for your EM12C.

Enterprise Manager Cloud Control URL:
Admin Server URL:


20. Just enter URL for EM12C cloud control and login as user sysman. Password for the user was specified in pt. 13.


21. Click “I Accept” button to accept “License Agreement”.


22. You should see invitation screen where you can choose your preferred home page. I’m DBA so I click “Databases” for Databases.



23. As last step I add new entry to .bash_profile of user oracle for EM12C software and new aliases to quickly navigate between binaries of EM and database. Installation is complete.


alias cdo='cd $ORACLE_OMS'
alias cdoa='cd $ORACLE_OMS_AGENT'
[oracle@oel6 ~]$ envo
[oracle@oel6 ~]$ alias | grep ORACLE
alias cdo='cd $ORACLE_OMS'
alias cdoa='cd $ORACLE_OMS_AGENT'
alias cdob='cd $ORACLE_BASE'
alias cdoh='cd $ORACLE_HOME'
alias envo='env | grep ORACLE | sort'
alias tns='cd $ORACLE_HOME/network/admin'

24. Quick commands for EM12C – all as user oracle

--start all
$ORACLE_OMS/bin/emctl start oms 
$ORACLE_OMS_AGENT/bin/emctl start agent
# Stop everything
$OARCLE_OMS/bin/emctl stop oms -all
$OARCLE_OMS_AGENT/bin/emctl stop agent

25. It’s time add some new targets to monitor in EM12C. If you click in top left menu Targets->Databases you won’t see any database on the screen.It could be surprise for you because we have on our host

To add this database click top right menu Setup->Add Target->Add Tragets Manually. Then select “Add Targets Using Guided Process (Also Adds Related Targets)” and select from list “Oracle Database, Listener and Automatic storage Management” then click button “Add Using Guided Process”.


26. Now you need to enter host where your database is installed. In my case it’s Remember agent EM12C must be installed on the host to discover the database !!!. In my case it was installed during installation of EM12C. Then click “Continue” button.


26. As you can see new 2 targets are discovered on by agent EM12C:

Now you need to configure communication between targets and EM12C. To do this just click on “Configure” for database.


27.You need to enter password for user DBSNMP to establish communication between database and EM12C. If you don’t know password for user DBSNMP you can always change it via sqlplus. There is possibility to test connection by clicking “Test Connection”. When you are done click “Next” button.


28. Just click “OK” button


29. Now when connection is established and verified save your new targets by clicking “Save” button.


30. Summary screen new targets saved. Click “OK” button.


31. After selecting Targets->Databases you should see list of your databases. Just click on entry now you should see details about your database.



Have a fun 🙂


4 thoughts on “Install Oracle Enterprise Manager 12C release 3( on OEL 5/6

  1. to install oem 12.1.04 i try to deinstall with this command oracle users
    emca -deconfig dbcontrol db -repos drop as you wrotes; so give me error
    — Invalid syntax
    and i wnat to use ora 12c database with oem so must be i deinstall 12c?
    Thank you..

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.