Oracle Database Learning: Part 2 – Installation & Initial Configuration

Installation Overview

Oracle 19c (19.3) is the long-term support (LTS) release recommended for production. We'll install it on Oracle Linux 8 / RHEL 8 — the preferred platform for Oracle Database.

Prerequisites

Hardware Requirements (Minimum for Lab)

• RAM: 2 GB minimum (8 GB recommended)
• Disk: 10 GB for software + 5 GB for database files
• CPU: x86-64 architecture

OS Prerequisites

# Install prerequisite packages (Oracle Linux / RHEL)
dnf install -y oracle-database-preinstall-19c

# Or manually for CentOS/RHEL
dnf install -y bc binutils elfutils-libelf elfutils-libelf-devel 
  fontconfig-devel glibc glibc-devel ksh libaio libaio-devel 
  libgcc librdmacm-devel libstdc++ libstdc++-devel libxcb 
  make net-tools nfs-utils python python-configshell smartmontools 
  sysstat targetcli unixODBC

Create Oracle OS User and Groups

groupadd -g 54321 oinstall
groupadd -g 54322 dba
groupadd -g 54323 oper
useradd -u 54321 -g oinstall -G dba,oper oracle
passwd oracle

# Create directory structure
mkdir -p /u01/app/oracle/product/19.3.0/dbhome_1
mkdir -p /u01/app/oraInventory
chown -R oracle:oinstall /u01
chmod -R 775 /u01

Set Kernel Parameters (/etc/sysctl.conf)

fs.aio-max-nr = 1048576
fs.file-max = 6815744
kernel.shmall = 2097152
kernel.shmmax = 4294967295
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
net.ipv4.ip_local_port_range = 9000 65500
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576

# Apply kernel parameters
sysctl -p

Oracle Environment Variables

# Add to ~oracle/.bash_profile
export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=/u01/app/oracle/product/19.3.0/dbhome_1
export ORACLE_SID=ORCL
export PATH=$ORACLE_HOME/bin:$PATH
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib
export NLS_DATE_FORMAT="DD-MON-YYYY HH24:MI:SS"

Silent Installation

# Unzip the installer
cd /u01/app/oracle/product/19.3.0/dbhome_1
unzip /tmp/LINUX.X64_193000_db_home.zip

# Run silent install
./runInstaller -silent -responseFile /tmp/db_install.rsp 
  oracle.install.option=INSTALL_DB_SWONLY 
  ORACLE_HOSTNAME=myserver.example.com 
  UNIX_GROUP_NAME=oinstall 
  INVENTORY_LOCATION=/u01/app/oraInventory 
  ORACLE_HOME=/u01/app/oracle/product/19.3.0/dbhome_1 
  ORACLE_BASE=/u01/app/oracle 
  oracle.install.db.InstallEdition=EE 
  oracle.install.db.DBA_GROUP=dba 
  oracle.install.db.OPER_GROUP=oper 
  DECLINE_SECURITY_UPDATES=true

# Run root scripts when prompted
/u01/app/oraInventory/orainstRoot.sh
/u01/app/oracle/product/19.3.0/dbhome_1/root.sh

Create Database Using DBCA

# GUI mode
dbca

# Silent mode
dbca -silent -createDatabase 
  -templateName General_Purpose.dbc 
  -gdbName ORCL 
  -sid ORCL 
  -responseFile NO_VALUE 
  -characterSet AL32UTF8 
  -sysPassword Oracle19c# 
  -systemPassword Oracle19c# 
  -createAsContainerDatabase true 
  -numberOfPDBs 1 
  -pdbName ORCLPDB 
  -pdbAdminPassword Oracle19c# 
  -databaseType MULTIPURPOSE 
  -memoryMgmtType AUTO_SGA 
  -totalMemory 2048 
  -storageType FS 
  -datafileDestination /u01/app/oracle/oradata 
  -redoLogFileSize 200 
  -emConfiguration NONE 
  -ignorePreReqs

Configure the Listener

# $ORACLE_HOME/network/admin/listener.ora
LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )

# Start listener
lsnrctl start

# Check status
lsnrctl status

Configure tnsnames.ora

# $ORACLE_HOME/network/admin/tnsnames.ora
ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521))
    (CONNECT_DATA = (SERVER = DEDICATED)(SERVICE_NAME = ORCL))
  )

ORCLPDB =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = myserver.example.com)(PORT = 1521))
    (CONNECT_DATA = (SERVER = DEDICATED)(SERVICE_NAME = ORCLPDB))
  )

Lab 2: First Connections

# Connect locally as SYSDBA
sqlplus / as sysdba

# Connect via listener
sqlplus sys/Oracle19c#@ORCL as sysdba
sqlplus system/Oracle19c#@ORCLPDB

-- Check status after startup
SQL> SELECT name, open_mode FROM v$pdbs;
SQL> ALTER PLUGGABLE DATABASE ORCLPDB OPEN;

-- Auto-open PDB on startup
SQL> ALTER PLUGGABLE DATABASE ORCLPDB SAVE STATE;

Common Installation Errors

INS-13001: Environment does not meet minimum requirements

# Solution: Run prerequisite package
dnf install -y oracle-database-preinstall-19c
# Then re-run installer with -ignorePrereq if in lab

ORA-12541: TNS: no listener

# Check listener is running
lsnrctl status
# Start if stopped
lsnrctl start

Summary

• Install OS prerequisites and create oracle OS user before installing
• Set ORACLE_HOME, ORACLE_BASE, ORACLE_SID in .bash_profile
• Use DBCA to create CDB with PDB — standard for 12c+
• Configure listener.ora and tnsnames.ora for network connectivity

Next: Part 3 – SQL Fundamentals: DDL & DML