Oracle 12c

Oracle Enterprise Manager Cloud Control 12c Release 1 Installation on Oracle Linux 5.7 and 6.1
Enterprise Manager Cloud Control is the new name for what was previously know as Enterprise Manager Grid Control. Depending on the source of the material, you may still see the product described as Grid Control. This article describes the installation of Oracle Enterprise Manager Cloud Control 12c Release 1 on Oracle Linux 5.7 and 6.1. (x86_64).

Software 
OS Installation 
Database Installation 
Cloud Control 12c Installation 
Startup/Shutdown 
Software
Download the following software:

Oracle Linux 5.7 or 6.1 (x86_64) 
Oracle Database 11gR2 (11.2.0.3) (x86_64) 
Enterprise Manager Cloud Control 12c Release 1 (12.1.0.1) (x86_64) 
Note. Previous versions of the database can be used to hold the repository, but anything earlier than 11.2.0.2 will require additional patches.

OS Installation
Install Oracle Linux (OL) 5.7 or 6.1 in the same way you would for a regular Oracle Database installation. You can see examples of these types of installations below. Remember to check the relevant database installation article (listed below) for the specific package group selection.

Oracle Linux 5.x Installation 
Oracle Linux 6.x Installation 
During this installation I used a virtual machine with 6G RAM and 30G disk space (40-50G would be better). The swap size was set at 8G and the firewall and SELinux were disabled.

Database Installation
Use one of the following articles to install the 11.2.0.3 database.

Oracle Database 11g Release 2 (11.2) Installation On Oracle Linux 5 
Oracle Database 11g Release 2 (11.2) Installation On Oracle Linux 6 
The installation documentation says the following packages are necessary for the cloud control installation. If you have performed the database installation as described in one of the above articles, these prerequisites will already have been met.

# OL 5.x and 6.x
make-3*
binutils-2*
gcc-4*
libaio-0*
glibc-common-2*
libstdc++-4*
sysstat-5*

# OL 5.x only
setarch-1*
rng-utils-2*
If you have performed a default database installation you will need to deconfigure Enterprise Manager Database Control. Run the following command as the "oracle" user.

$ emca -deconfig dbcontrol db -repos drop -SYS_PWD  -SYSMAN_PWD Make the following initialization parameter changes and restart the instance.

sqlplus / AS SYSDBA

ALTER SYSTEM SET processes=300 SCOPE=SPFILE;
ALTER SYSTEM SET session_cached_cursors=200 SCOPE=SPFILE;
ALTER SYSTEM SET sga_target=2G SCOPE=SPFILE;
ALTER SYSTEM SET shared_pool_size=600M SCOPE=SPFILE;
ALTER SYSTEM SET pga_aggregate_target=1G SCOPE=SPFILE;
ALTER SYSTEM SET job_queue_processes=20 SCOPE=SPFILE;

-- May be required if using older versions of DB.
--ALTER SYSTEM SET log_buffer=10485760 SCOPE=SPFILE;
--ALTER SYSTEM SET open_cursors=300 SCOPE=SPFILE;

-- Restart the instance.
SHUTDOWN IMMEDIATE
STARTUPIf you have done a default installation as described here, the UNDO tablespace will be autoextensible. If you have done a custom installation make sure the UNDO tablespace is at least 200M in size. Also, make sure you have 3 redo logs of at least 300M to prevent a warning during the installation.

The database installation is now complete.

Cloud Control 12c Installation
Make a directory to hold the Middleware installation.

http://docs.oracle.com/cd/E24628_01/install.121/e22624/part_preinstall_reqs.htm