Install Oracle database 11g. X Window system is needed for it.
[1] Install some packages first for dependencies.
[root@www ~]#
yum -y install binutils compat-libstdc++-33 elfutils-libelf elfutils-libelf-devel glibc glibc-common glibc-devel gcc gcc-c++ libaio libaio-devel libgcc libstdc++ libstdc++-devel make sysstat unixODBC unixODBC-devel
[2] Edit kernel parameter.
[root@www ~]#
vi /etc/sysctl.conf


# add at the bottom

kernel.sem = 250 32000 100 128
fs.file-max = 65536
net.ipv4.ip_local_port_range = 1024 65000
net.core.rmem_default = 4194304
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 262144


[root@www ~]#
sysctl -p

net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 4294967295
kernel.shmall = 268435456
net.ipv4.icmp_echo_ignore_broadcasts = 0
kernel.sem = 250 32000 100 128
fs.file-max = 65536
net.ipv4.ip_local_port_range = 32768 65000
net.core.rmem_default = 4194304
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 262144
[3] Create users and groups and set environment for Oracle.
[root@www ~]#
groupadd -g 200 oinstall

[root@www ~]#
groupadd -g 201 dba

[root@www ~]#
useradd -u 440 -g oinstall -G dba -d /usr/oracle oracle

[root@www ~]#
passwd oracle

Changing password for user oracle.
New UNIX password:
Retype new UNIX password:
passwd: all authentication tokens updated successfully.
[root@www ~]#
chmod 755 /usr/oracle

[root@www ~]#
mkdir /usr/oracle/app

[root@www ~]#
chown -R oracle:oinstall /usr/oracle/app

[root@www ~]#
chmod -R 775 /usr/oracle/app

[root@www ~]#
mkdir /usr/oracle/oradata

[root@www ~]#
chown -R oracle:oinstall /usr/oracle/oradata

[root@www ~]#
chmod -R 775 /usr/oracle/oradata

[root@www ~]#
vi /etc/pam.d/login


# add at the bottom

session required /lib/security/pam_limits.so
session required pam_limits.so


[root@www ~]#
vi /etc/security/limits.conf


# add at the bottom

oracle soft nproc 2047
oracle hard nproc 16384
oracle soft nofile 1024
oracle hard nofile 65536


[root@www ~]#
vi /etc/profile


# add at the bottom

if [ $USER = "oracle" ]; then
if [ $SHELL = "/bin/ksh" ]; then
ulimit -p 16384
ulimit -n 65536
else
ulimit -u 16384 -n 65536
fi
fi


[root@www ~]#
vi /usr/oracle/.bash_profile


# add at the bottom

umask 022
export ORACLE_BASE=/usr/oracle/app

[4] Downlodad and install Oracle 11g. Do them with a user "Oracle" taht is created on section [3].
[oracle@www ~]$
mkdir tmp# create temporary dir
Download Oracle 11g for Linux from the site below. First, you have to register and login on the site.
After downloading, unzip it and run installer like following example.
[oracle@www ~]$
cd tmp

[oracle@www tmp]$
unzip linux_x86_11gR1_database.zip

[oracle@www tmp]$
database/runInstaller
(1) Installer starts like below. uncheck "Create Starter Database" and Click "Next".
(2) It's OK, Go next.
(3) It's OK, Go next.
(4) Click "Install" button and start installation.
(5) Installation proceeds.
(6) It's necessary to run config scripts that shows on the screen below with root user. After running, come back to this screen and Click "OK" button
[root@ns ~]#
/usr/oracle/oraInventory/orainstRoot.sh

Changing permissions of /usr/oracle/oraInventory to 770.
Changing groupname of /usr/oracle/oraInventory to oinstall.
The execution of the script is complete
[root@ns ~]#
/usr/oracle/app/product/11.1.0/db_2/root.sh

Running Oracle 11g root.sh script...

The following environment variables are set as:
ORACLE_OWNER= oracle
ORACLE_HOME= /usr/oracle/app/product/11.1.0/db_2

Enter the full pathname of the local bin directory: [/usr/local/bin]:
# Enter

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.sh script.
Now product-specific root actions will be performed.
Finished product-specific root actions.
(7) Installation completes. Click "Exit" button.
[5] Set environment for Oracle user and remove temporary directory.
[oracle@www ~]$
vi .bash_profile


# add at the bottom

export ORACLE_HOME=$ORACLE_BASE/product/11.1.0/db_2
export PATH=$PATH:$ORACLE_HOME/bin


[oracle@www ~]$
. .bash_profile

[oracle@www ~]$
rm -rf tmp
Finish
(server-world.info)