fs.file-max = 6815744
kernel.sem = 250 32000 100 128
kernel.shmmni = 4096
kernel.shmall = 1073741824
kernel.shmmax = 4398046511104
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
fs.aio-max-nr = 1048576
net.ipv4.ip_local_port_range = 9000 65500

/sbin/sysctl -p

oracle   soft   nofile   1024
oracle   hard   nofile   65536
oracle   soft   nproc    2047
oracle   hard   nproc    16384
oracle   soft   stack    10240
oracle   hard   stack    32768

5. Check and install following packages

yum install binutils -y
yum install compat-libcap1 -y
yum install compat-libstdc++-33 -y
yum install compat-libstdc++-33.i686 -y
yum install gcc -y
yum install gcc-c++ -y
yum install glibc -y
yum install glibc.i686 -y
yum install glibc-devel -y
yum install glibc-devel.i686 -y
yum install ksh -y
yum install libgcc -y
yum install libgcc.i686 -y
yum install libstdc++ -y
yum install libstdc++.i686 -y
yum install libstdc++-devel -y
yum install libstdc++-devel.i686 -y
yum install libaio -y
yum install libaio.i686 -y
yum install libaio-devel -y
yum install libaio-devel.i686 -y
yum install libXext -y
yum install libXext.i686 -y
yum install libXtst -y
yum install libXtst.i686 -y
yum install libX11 -y
yum install libX11.i686 -y
yum install libXau -y
yum install libXau.i686 -y
yum install libxcb -y
yum install libxcb.i686 -y
yum install libXi -y
yum install libXi.i686 -y
yum install make -y
yum install sysstat -y
yum install unixODBC -y
yum install unixODBC-devel -y

6. Create new group and user

groupadd -g 54321 oracle
useradd -u 54321 -g oracle oracle
passwd oracle

7. Amend the /etc/security/limits.d/90-nproc.conf

# Change this
*          soft    nproc    1024

# To this
* - nproc 16384

8. Change the setting of SELinux to permissive by editing the /etc/selinux/config

SELINUX=permissive

9. Set firewall to enable Oracle DB ports

touch /etc/oratab
chown -R oracle:oracle /etc/oratab

mkdir -p /u01
chown -R oracle:oracle /u01

12. Unzip installer and run installer

1) /u01/app/oraInventory/orainstRoot.sh

[root@ol65 oraInventory]# ./orainstRoot.sh
Changing permissions of /u01/app/oraInventory.
Adding read,write permissions for group.
Removing read,write,execute permissions for world.
Changing groupname of /u01/app/oraInventory to oracle.
The execution of the script is complete.

2) /u01/app/oracle/product/12.1.0/dbhome_1/root.sh

[root@ol65 dbhome_1]# ./root.sh
Performing root user operation.

The following environment variables are set as:
   ORACLE_OWNER= oracle
   ORACLE_HOME=  /u01/app/oracle/product/12.1.0/dbhome_1

Enter the full pathname of the local bin directory: [/usr/local/bin]:
  Copying dbhome to /usr/local/bin ...
  Copying oraenv to /usr/local/bin ...
  Copying coraenv to /usr/local/bin ...


Creating /etc/oratab file...
Entries will be added to the /etc/oratab file as needed by
Database Configuration Assistant when a database is created
Finished running generic part of root script.
Now product-specific root actions will be performed.

# Oracle12c Settings
export TMP=/tmp
export TMPDIR=$TMP
export ORACLE_HOSTNAME=oracle12c.localdomain
export ORACLE_UNQNAME=oracle12c
export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/12.1.0/dbhome_1
export ORACLE_SID=orcl
export PATH=/usr/sbin:$PATH:$ORACLE_HOME/bin
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

16. Set auto startup

1) Edit /etc/oratab, change N to Y as below

orcl:/u01/app/oracle/product/12.1.0/dbhome_1:Y

#!/bin/sh
# chkconfig: 345 99 10
# description: Service to start and stop Oracle Database and Listener
#
# processname: oracle
# config: /etc/oratab
# pidfile: /var/run/oracle.pid

# Source function library.
. /etc/init.d/functions

RETVAL=0
ORA_OWNER="oracle"
ORA_HOME="/u01/app/oracle/product/12.1.0/dbhome_1"

# See how we were called.

prog="oracle"

start() {
echo -n $"Starting $prog: "
su - $ORA_OWNER -c "$ORA_HOME/bin/dbstart $ORA_HOME"
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && touch /var/lock/subsys/dbora

return $RETVAL
}

stop() {
echo -n $"Stopping $prog: "
su - $ORA_OWNER -c "$ORA_HOME/bin/dbshut $ORA_HOME"
RETVAL=$?
echo
[ $RETVAL -eq 0 ] && rm -r /var/lock/subsys/dbora

return $RETVAL
}

restart() {
stop
start
}

case "$1" in
start)
start
;;
stop)
stop
;;
restart)
restart
;;
*)
echo $"Usage: $0 {start|stop|restart}"
exit 1
esac

exit $?

Next you need to run the following commands to change permissions and make the service active.

chgrp oracle /etc/init.d/dbora 
chmod 755 /etc/init.d/dbora 
chkconfig --level 345 dbora on

reboot