Share on Social Media

Learn how to install Oracle Database 21c on RHEL 8 with this comprehensive step-by-step guide. Ensure a smooth setup of Oracle’s latest database technology on your Linux system. #centlinux #linux #oracle

What is Oracle Database?

Oracle Database, developed by Oracle Corporation, is one of the most widely used and powerful relational database management systems (RDBMS) in the world. It is designed to efficiently manage a large amount of data and support multiple concurrent users, making it suitable for a variety of enterprise-level applications. Here’s an overview of Oracle Database:

Key Features of Oracle Database

  • Relational Database Management: Organizes data into tables that can be related based on data common to each. This structure allows for complex querying and data management.
  • Multimodel Database: Supports not only traditional relational data but also JSON, XML, spatial, graph, and other types of data, allowing for versatile data management within a single database system.
  • High Availability and Scalability: Features like Real Application Clusters (RAC), Data Guard, and GoldenGate ensure high availability and disaster recovery. Oracle Database can scale vertically (adding resources to a single server) and horizontally (adding more servers).
  • Performance: Advanced indexing, partitioning, and caching mechanisms, along with features like Oracle Exadata, enhance performance for both transaction processing and data warehousing.
  • Security: Comprehensive security features including encryption, data masking, auditing, and access controls to protect sensitive data and ensure regulatory compliance.
  • Automation and Management: Tools like Oracle Enterprise Manager and Autonomous Database capabilities automate many routine management tasks such as patching, tuning, backups, and upgrades, reducing administrative overhead.
  • Cloud Integration: Supports hybrid and multi-cloud environments with seamless integration into Oracle Cloud Infrastructure (OCI) and other cloud platforms, providing flexible deployment options.
  • Advanced Analytics and Machine Learning: Built-in analytics and machine learning capabilities allow users to perform sophisticated data analysis and build predictive models directly within the database.
  • Application Development: Supports various programming languages and frameworks, including PL/SQL, Java, Python, and RESTful services, facilitating the development of modern applications.
  1. Data Warehousing and Big Data: Specialized features for data warehousing, such as Oracle Exadata, and big data integration, support complex analytical queries and large-scale data processing.

Use Cases

  • Enterprise Resource Planning (ERP): Manages core business processes like finance, HR, and supply chain with high efficiency and reliability.
  • Customer Relationship Management (CRM): Powers CRM systems by managing vast amounts of customer data and transaction records.
  • Data Warehousing: Enables businesses to consolidate data from various sources into a single repository for analysis and reporting.
  • E-commerce: Supports online retail operations by handling high transaction volumes and ensuring data security.
  • Healthcare: Manages patient records and healthcare data, ensuring compliance with regulations like HIPAA.
  • Financial Services: Processes and secures transactions for banking, investment, and insurance applications.


  • Reliability and Stability: Trusted for mission-critical applications due to its robustness and reliability.
  • Comprehensive Ecosystem: Wide range of tools and resources for database management, development, and analytics.
  • Support and Community: Strong support from Oracle and a large user community, providing resources and assistance for troubleshooting and optimization.


Oracle Database is a powerful, versatile, and secure RDBMS that supports a wide range of applications and data types. Its comprehensive feature set and scalability make it a preferred choice for large enterprises and mission-critical applications across various industries.

Recommended Books: Red Hat RHCE 8 (EX294) Cert Guide (Certification Guide) 1st Edition (PAID LINK) by Sander van Vugt
Recommended Online Training: Become an Oracle Database Administrator (DBA)

1110388 63ec 2show?id=oLRJ54lcVEg&offerid=1074652.1110388&bids=1074652

New Features in Oracle Database 21c:

The distinct features of Oracle Database 21c are:

  • Blockchain Tables
  • Multilingual Engine – JavaScript Execution in the Database
  • Binary JSON Data Type
  • Per-PDB Data Guard Physical Standby (aka Multitenant Data Guard)
  • Per-PDB GoldenGate Change Capture
  • Self-Managing In-Memory
  • In-Memory Hybrid Columnar Scan
  • In-Memory Vector Joins with SIMD
  • Sharding Advisor Tool
  • Property Graph Visualization Studio
  • Automatic Materialized Views
  • Automatic Zone Maps
  • SQL Macros
  • Gradual Password Rollover

Environment Specification

We are using a minimal Red Hat Enterprise Linux 8 virtual machine with following specifications.

  • CPU – 3.4 Ghz (2 cores)
  • Memory – 2 GB
  • Storage – 20 GB
  • Operating System – Red Hat Enterprise Linux 8.5
  • Hostname –
  • IP Address – /24

Oracle Database Preinstallation Configuration

Set Hostname and Local DNS Resolution

By using a SSH client, connect with as root user.

Set an appropriate hostname for your Oracle Database server with the help of following Linux command.

# hostnamectl set-hostname

Execute following command to add an entry in Local DNS Resolver or you can use a DNS server (if available).

# echo " oracle-01" >> /etc/hosts

Update Linux Operating System

It is the best practice to update your Linux operating system before a new software installation. Therefore, use following dnf commands to update your exisiting software packages.

# dnf makecache
# dnf update -y

If Package Manager updates your Linux Kernel, then you should reboot your Linux operating system with the new Kernel.

# reboot

Verify the Linux Kernel and Operating System versions that are being used in this installation guide.

# uname -r

# cat /etc/redhat-release
Red Hat Enterprise Linux release 8.5 (Ootpa)

Disable Transparent HugePages in RHEL 8

Oracle recommends that you disable Transparent HugePages, because they may cause delays in accessing memory that can result in node restarts in Oracle RAC environments and performance issues or delays for Oracle Database single instances. Instead, Oracle recommends using Standard HugePages for Linux based operating systems.

Transparent HugePages are enable by default in EL (Enterprise Linux) 6 or later.

Verify that Transparent HugePages are enabled on your Linux server.

# cat /sys/kernel/mm/transparent_hugepage/enabled
always madvise [never]

We have already disabled the Transparent HugePages in our Linux server. You can do the same by following our previous article about how to disable transparent hugepages.

Install Oracle Database 21c Prerequisites

For proper functioning Oracle Database 21c depends upon various third party software packages.

Fortunately, all these required packages are available in RHEL 8 default yum repositories. Execute following dnf command to install all these prerequisites in one go.

Make sure you have acquire an active Red Hat Subscription or you may not complete this step successfully.

# dnf install -y  
> bc 
> binutils 
> compat-openssl10 
> elfutils-libelf 
> glibc 
> glibc-devel 
> ksh 
> libaio 
> libXrender 
> libX11 
> libXau 
> libXi 
> libXtst 
> libgcc 
> libnsl 
> libstdc++ 
> libxcb 
> libibverbs 
> make 
> policycoreutils 
> policycoreutils-python-utils 
> smartmontools 
> sysstat 
> libnsl2 
> libnsl2-devel 
> net-tools 
> nfs-utils 
> unzip

Create Linux Users and Groups

Create Linux users and groups as required by Oracle Database 21c.

# groupadd -g 1501 oinstall
# groupadd -g 1502 dba
# groupadd -g 1503 oper
# groupadd -g 1504 backupdba
# groupadd -g 1505 dgdba
# groupadd -g 1506 kmdba
# groupadd -g 1507 racdba
# useradd -u 1501 -g oinstall -G dba,oper,backupdba,dgdba,kmdba,racdba oracle
# echo "oracle" | passwd oracle --stdin
Changing password for user oracle.
passwd: all authentication tokens updated successfully.

Set Security limits for oracle user

Create a configuration file in /etc/security/limits.d directory, to set the security limits for the oracle user.

# vi /etc/security/limits.d/30-oracle.conf

Add following lines in this file.

oracle   soft   nofile   1024
oracle   hard   nofile   65536
oracle   soft   nproc    16384
oracle   hard   nproc    16384
oracle   soft   stack    10240
oracle   hard   stack    32768
oracle   hard   memlock  134217728
oracle   soft   memlock  134217728
oracle   soft   data     unlimited
oracle   hard   data     unlimited

Set Linux Kernel Parameters

Create a configuration file in /etc/sysctl.d directory.

# vi /etc/sysctl.d/98-oracle.conf

Set the following Linux Kernel parameters as required by the Oracle Database 21c.

fs.file-max = 6815744
kernel.sem = 250 32000 100 128
kernel.shmmni = 4096
kernel.shmall = 1073741824
kernel.shmmax = 4398046511104
kernel.panic_on_oops = 1
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
net.ipv4.conf.all.rp_filter = 2
net.ipv4.conf.default.rp_filter = 2
fs.aio-max-nr = 1048576
net.ipv4.ip_local_port_range = 9000 65500

Reload Kernel parameters now by using sysctl command.

# sysctl -p

Configure SELinux Target Mode

Persistently set SELinux mode to permissive.

# sed -i 's/^SELINUX=.*/SELINUX=permissive/g' /etc/selinux/config
# setenforce permissive

Configure Linux Firewall

Allow Oracle SQL* Net Listener port 1521/tcp in Linux Firewall.

# firewall-cmd --permanent --add-port=1521/tcp
# firewall-cmd --reload

Create Directories for Oracle Database 21c

Create the necessary directories for Oracle software and adjust the ownership and permissions on these directories.

# mkdir -p /u01/app/oracle/product/21.3.0/dbhome_1
# mkdir -p /u02/oradata
# chown -R oracle:oinstall /u01 /u02
# chmod -R 775 /u01 /u02

Here, we have created two directories, /u01 for the Oracle RDBMS and /u02 for the Oracle Databases.

Configure Linux Environment for Oracle User

Connect as oracle user and open .bash_profile in vim text editor.

# su - oracle
$ vi ~/.bash_profile

Add following lines to set environment variables for oracle user.

# Oracle Settings
export TMP=/tmp
export TMPDIR=$TMP

export ORACLE_UNQNAME=cdb1
export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/21.3.0/dbhome_1
export ORA_INVENTORY=/u01/app/oraInventory
export ORACLE_SID=cdb1
export PDB_NAME=pdb1
export DATA_DIR=/u02/oradata


export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

Manually execute the .bash_profile to set the environment for current Linux shell.

$ source ~/.bash_profile

Install Oracle Database 21c on RHEL 8

You can download Oracle Database 21c from Oracle official website. You have to create a free Oracle Single Sign-On account to login and download the software.

Oracle Database 21c Downloads
Oracle Database 21c Downloads

We have downloaded Oracle Database 21c (21.3) for Linux and transferred it into home directory of oracle user.

Unzip the downloaded zip file to ORACLE_HOME directory.

$ unzip -d $ORACLE_HOME

Go to ORACLE_HOME directory and start Oracle Database 21c installation in silent mode.

$ ./runInstaller -ignorePrereq -waitforcompletion -silent 
> oracle.install.option=INSTALL_DB_SWONLY 
> UNIX_GROUP_NAME=oinstall 
> oracle.install.db.InstallEdition=EE 
> oracle.install.db.OSDBA_GROUP=dba 
> oracle.install.db.OSBACKUPDBA_GROUP=backupdba 
> oracle.install.db.OSDGDBA_GROUP=dgdba 
> oracle.install.db.OSKMDBA_GROUP=kmdba 
> oracle.install.db.OSRACDBA_GROUP=racdba 
Launching Oracle Database Setup Wizard...

The response file for this session can be found at:

You can find the log of this install session at:

As a root user, execute the following script(s):
        1. /u01/app/oraInventory/
        2. /u01/app/oracle/product/21.3.0/dbhome_1/

Execute /u01/app/oraInventory/ on the following nodes:


 Execute /u01/app/oracle/product/21.3.0/dbhome_1/ on the following nodes: 


Successfully Setup Software. Moved the install session logs to:  /u01/app/oraInventory/logs/InstallActions2021-12-10_08-46-35AM 

Connect as root user and execute post-installation scripts.

$ su -
Last login: Fri Dec 10 08:23:01 EST 2021 from on pts/0
# /u01/app/oraInventory/
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 oinstall.
The execution of the script is complete.

# /u01/app/oracle/product/21.3.0/dbhome_1/
Check /u01/app/oracle/product/21.3.0/dbhome_1/install/root_oracle-01.centlinux.com_2021-12-10_09-16-32-458187002.log for the output of root script
# exit

Oracle Database 21c has been installed on Red Hat Enterprise Linux 8.

Create an Oracle Multitenant Database

Start Oracle Listener

Start Oracle Listener by executing following command.

$ lsnrctl start
LSNRCTL for Linux: Version - Production on 10-DEC-2021 09:18:26

Copyright (c) 1991, 2021, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/21.3.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version - Production
Log messages written to /u01/app/oracle/diag/tnslsnr/oracle-01/listener/alert/log.xml

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version - Production
Start Date                10-DEC-2021 09:18:26
Uptime                    0 days 0 hr. 0 min. 0 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Log File         /u01/app/oracle/diag/tnslsnr/oracle-01/listener/alert/log.xml
Listening Endpoints Summary...
The listener supports no services
The command completed successfully

Create Multitenant Database

Create an Oracle Multitenant database by using the following command.

$ dbca -silent -createDatabase 
> -templateName General_Purpose.dbc 
> -gdbname ${ORACLE_SID} 
> -sid ${ORACLE_SID} 
> -responseFile NO_VALUE 
> -characterSet AL32UTF8 
> -sysPassword Str@ngP@55 
> -systemPassword Str@ngP@55 
> -createAsContainerDatabase true 
> -numberOfPDBs 1 
> -pdbName ${PDB_NAME} 
> -pdbAdminPassword Str@ngP@55 
> -databaseType MULTIPURPOSE 
> -automaticMemoryManagement false 
> -totalMemory 800 
> -storageType FS 
> -datafileDestination "${DATA_DIR}" 
> -redoLogFileSize 50 
> -emConfiguration NONE 
> -ignorePreReqs
Prepare for db operation
8% complete
Copying database files
31% complete
Creating and starting Oracle instance
32% complete
36% complete
40% complete
43% complete
46% complete
Completing Database Creation
51% complete
53% complete
54% complete
Creating Pluggable Databases
58% complete
77% complete
Executing Post Configuration Actions
100% complete
Database creation complete. For details check the logfiles at:
Database Information:
Global Database Name:cdb1
System Identifier(SID):cdb1
Look at the log file "/u01/app/oracle/cfgtoollogs/dbca/cdb1/cdb1.log" for further details.

Switch to root user and execute following command to enable autostart of Oracle database instances.

$ su -
Last login: Fri Dec 10 10:04:05 EST 2021 on pts/0
# sed -i 's/:N$/:Y/g' /etc/oratab
# exit

Connect to SQL Shell by using sqlplus command.

$ sqlplus / as sysdba

SQL*Plus: Release - Production on Fri Dec 10 10:09:09 2021

Copyright (c) 1982, 2021, Oracle.  All rights reserved.

Connected to:
Oracle Database 21c Enterprise Edition Release - Production


Enable Oracle Managed File (OMF) to simplify the creation of databases and database files.


System altered.

Enable autostart of Pluggable databases with the startup of Container Database.


Pluggable database altered.

SQL> exit
Disconnected from Oracle Database 21c Enterprise Edition Release - Production

Configure AutoStart of Oracle Database Server

To configure autostart of Oracle Database 21c on Red Hat Enterprise Linux 8, you have to create a Systemd service.

Switch to root user and create a Systemd service unit by using vim text editor.

$ su -
Last login: Fri Dec 10 10:06:34 EST 2021 on pts/0
# vi /usr/lib/systemd/system/dbora.service

Add following directives in this file.

Description=Oracle Database Service

ExecStart=/u01/app/oracle/product/21.3.0/dbhome_1/bin/dbstart /u01/app/oracle/product/21.3.0/dbhome_1
ExecStop=/u01/app/oracle/product/21.3.0/dbhome_1/bin/dbshut /u01/app/oracle/product/21.3.0/dbhome_1


Execute following command to notify Systemd about changes in unit files.

# systemctl daemon-reload

Enable and start Oracle Database 21c service.

# systemctl enable --now dbora.service
Created symlink /etc/systemd/system/ → /usr/lib/systemd/system/dbora.service.

Verify the status of the Oracle Database 21c service.

# systemctl status dbora.service
● dbora.service - Oracle Database Service
   Loaded: loaded (/usr/lib/systemd/system/dbora.service; enabled; vendor prese>
   Active: active (running) since Fri 2021-12-10 21:11:43 EST; 40s ago
  Process: 1761 ExecStart=/u01/app/oracle/product/21.3.0/dbhome_1/bin/dbstart />
 Main PID: 1772 (tnslsnr)
    Tasks: 1 (limit: 12267)
   Memory: 5.0M
   CGroup: /system.slice/dbora.service
           └─1772 /u01/app/oracle/product/21.3.0/dbhome_1/bin/tnslsnr LISTENER >

Dec 10 21:11:42 systemd[1]: Starting Oracle Database Se>
Dec 10 21:11:43 dbstart[1761]: Processing Database inst>
Dec 10 21:11:43 systemd[1]: Started Oracle Database Ser>

Final Thoughts

Installing Oracle Database 21c on RHEL 8 can be a complex process, but with the right guidance, it becomes manageable. This guide aims to provide you with clear, step-by-step instructions to ensure a smooth installation. However, if you need professional assistance or run into any issues, I’m here to help.

Check out my Fiverr profile here to explore my services. I offer expert installation and configuration of Oracle Database, as well as other database management and server setup services. Let me handle the technical details so you can focus on leveraging the full potential of your database.

5 thoughts on “How to install Oracle Database 21c on RHEL 8”
  1. Thank you for such an easy and well-defined article. It helped me in successful installation of oracle database and helped me resolve an error on which I was stuck since several days.

Leave a Reply

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