How to Install Oracle Database 21c on Linux

We supposed that you already have installed Oracle Linux 8, Red Hat Enterprise Linux 8 or its derivatives like AlmaLinux for your database server.

There're 5 major sections of installing an Oracle database 21c on Linux.

Prepare Database Server
Install Oracle Software 21c
Configure Listener
Create Database 21c
Post Installation

Please note that, if you want your database server to have a higher state of 21c directly, say 21.10, you may also consider to patch oracle home before creating the database, it's faster and less risky.

There's a tutorial that directly install Oracle database 19.18 on a new Linux server, you may have a look.

Prepare Database Server

To prepare a database server, we take the following steps.

Required Packages
Network & Security
Kernel Parameters
Group, User and Directories
User Profile
Unzip Sources

Required Packages

A newly created Linux server might not have sufficient packages to run Oracle products, especially you chose the minimal install for it. Therefore, we have to install required packages for Oracle database 21c.

Network & Security

Check Hostname Resolution

To prevent DBT-06103 The Port 5500 is Already in Use, we should make sure that the hostname resolution is working on this server.


[root@test ~]# vi /etc/hosts

...

192.168.1.11    test test.example.com

Disable Firewall


[root@test ~]# systemctl stop firewalld

[root@test ~]# systemctl disable firewalld

Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.

Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

If you couldn't or wouldn't disable firewall, then you may also open port 1521 on Linux for your listener.

Disable SELinux

We changed SELINUX from enforcing to disabled.


[root@test ~]# vi /etc/selinux/config

...

SELINUX=disabled

Kernel Parameters

If required packages were installed through Oracle Database 21c Pre-installation RPM, you may skip this step. Otherwise, you have to change kernel parameters by yourself.

Persist Kernel Parameter

We put new kernel values in a sysctl configuration file.


[root@test ~]# vi /etc/sysctl.d/97-oracle-database-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

Reload Kernel Parameter

We should make it read values from all system directories.


[root@test ~]# sysctl --system

* Applying /usr/lib/sysctl.d/10-default-yama-scope.conf ...

kernel.yama.ptrace_scope = 0

* Applying /usr/lib/sysctl.d/50-coredump.conf ...

kernel.core_pattern = |/usr/lib/systemd/systemd-coredump %P %u %g %s %t %c %h %e

kernel.core_pipe_limit = 16

* Applying /usr/lib/sysctl.d/50-default.conf ...

kernel.sysrq = 16

kernel.core_uses_pid = 1

kernel.kptr_restrict = 1

net.ipv4.conf.all.rp_filter = 1

net.ipv4.conf.all.accept_source_route = 0

net.ipv4.conf.all.promote_secondaries = 1

net.core.default_qdisc = fq_codel

fs.protected_hardlinks = 1

fs.protected_symlinks = 1

* Applying /usr/lib/sysctl.d/50-libkcapi-optmem_max.conf ...

net.core.optmem_max = 81920

* Applying /usr/lib/sysctl.d/50-pid-max.conf ...

kernel.pid_max = 4194304

* Applying /etc/sysctl.d/97-oracle-database-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

* Applying /etc/sysctl.d/99-sysctl.conf ...

* Applying /etc/sysctl.conf ...

Group, User and Directories

At least, we should create 2 groups and 1 user for installing a single-instance database.


[root@test ~]# groupadd -g 54321 oinstall

[root@test ~]# groupadd -g 54322 dba

[root@test ~]# groupadd -g 54323 oper

[root@test ~]# useradd -u 54321 -g oinstall -G dba,oper oracle

[root@test ~]# id oracle

uid=54321(oracle) gid=54321(oinstall) groups=54321(oinstall),54322(dba),54323(oper)

[root@test ~]# passwd oracle

Changing password for user oracle.

New password:

Retype new password:

passwd: all authentication tokens updated successfully.

Then we create necessary directories for user oracle.


[root@test ~]# mkdir -p /u01/app/oracle/product/21.0.0/dbhome_1

[root@test ~]# chown -R oracle:oinstall /u01

[root@test ~]# chmod -R 775 /u01

Resource management should also be configured for the user.


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

...

oracle soft nofile 1024

oracle hard nofile 65536

oracle soft nproc 2047

oracle hard nproc 16384

oracle soft stack 10240

oracle hard stack 32768

oracle soft memlock unlimited

oracle hard memlock unlimited

[root@test ~]# sysctl -p

User Profile

To prepare the environment of the software owner, we modify its profile (~/.bash_profile).


[root@test ~]# su - oracle

[oracle@test ~]$ vi ~/.bash_profile

...

# User specific environment and startup programs

umask 022

ORACLE_SID=ORCLCDB

ORACLE_BASE=/u01/app/oracle

ORACLE_HOME=$ORACLE_BASE/product/21.0.0/dbhome_1

LD_LIBRARY_PATH=$ORACLE_HOME/lib

TMP=/tmp

TMPDIR=/tmp

PATH=$PATH:$ORACLE_HOME/bin:$ORACLE_HOME/OPatch

export ORACLE_SID ORACLE_BASE ORACLE_HOME LD_LIBRARY_PATH TMP TMPDIR PATH

Unzip Sources

Supposed that you have uploaded the software to the database server, we may unzip the software to $ORACLE_HOME by the owner oracle.

Please login the database server as oracle directly through ssh -X or any other tools with X window enabled by default.


[oracle@test ~]$ ll /sources/

total 3036356

-rwxr-xr-x. 1 oracle oinstall 3109225519 Jun 13 15:54 LINUX.X64_213000_db_home.zip

drwxr-xr-x. 2 oracle oinstall         47 Jun 13 16:20 patches

[oracle@test ~]$ unzip -q /sources/LINUX.X64_213000_db_home.zip -d $ORACLE_HOME

To know if the server meets the requirements of Oracle product or not, we may perform a prerequisite check before installation.

Install Oracle Software 21c

Here we initiate runInstaller GUI to install it. Alternatively, you may install Oracle software 21c in silent mode.


[oracle@test ~]$ cd $ORACLE_HOME

[oracle@test dbhome_1]$ ./runInstaller

Launching Oracle Database Setup Wizard...


The response file for this session can be found at:

 /u01/app/oracle/product/21.0.0/dbhome_1/install/response/db_2023-06-13_05-25-04PM.rsp



You can find the log of this install session at:

 /tmp/InstallActions2023-06-13_05-25-04PM/installActions2023-06-13_05-25-04PM.log

Moved the install session logs to:

 /u01/app/oraInventory/logs/InstallActions2023-06-13_05-25-04PM

Configure Listener

The step is optional, because you can create a new listener in Database Configuration Assistant (DBCA).

To configure a new listener, we issue netca command (Net Configuration Assistant).


[oracle@test dbhome_1]$ netca


Oracle Net Services Configuration:

Configuring Listener:LISTENER

Listener configuration complete.

Oracle Net Listener Startup:

    Running Listener Control:

      /u01/app/oracle/product/21.0.0/dbhome_1/bin/lsnrctl start LISTENER

    Listener Control complete.

    Listener started successfully.

Oracle Net Services configuration successful. The exit code is 0

To trace back the process, you may check the log of NETCA.

Create Database 21c

To create a new database, we issue dbca command (Database Configuration Assistant).


[oracle@test dbhome_1]$ dbca

To trace back the creation process, you may check the log of DBCA.

The TNSNAME of CDB will be automatically added to tnsnames.ora file after DBCA, but not for PDB. For adding more TNSNAME, you may edit the file or add net service names through NETCA, if you like GUI style.

Post Installation

We have to make sure that everything is running well.

Check Listener


[oracle@test dbhome_1]$ lsnrctl status



LSNRCTL for Linux: Version 21.0.0.0.0 - Production on 13-JUN-2023 18:01:44

...

Listener Parameter File   /u01/app/oracle/homes/OraDB21Home1/network/admin/listener.ora

Listener Log File         /u01/app/oracle/diag/tnslsnr/test/listener/alert/log.xml

Listening Endpoints Summary...

  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=test)(PORT=1521)))

  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))

  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=test)(PORT=5500))(Security=(my_wallet_directory=/u01/app/oracle/admin/ORCLCDB/xdb_wallet))(Presentation=HTTP)(Session=RAW))

Services Summary...

Service "ORCLCDB" has 1 instance(s).

  Instance "ORCLCDB", status READY, has 1 handler(s) for this service...

Service "ORCLCDBXDB" has 1 instance(s).

  Instance "ORCLCDB", status READY, has 1 handler(s) for this service...

Service "fe000d81480a2b61e0530b01a8c0ad64" has 1 instance(s).

  Instance "ORCLCDB", status READY, has 1 handler(s) for this service...

Service "orclpdb" has 1 instance(s).

  Instance "ORCLCDB", status READY, has 1 handler(s) for this service...

The command completed successfully

Did you see that? the location of listener parameter has been different from our sense.

Read-Only Oracle Home

That's because Read-Only ORACLE_HOME is now the default feature since 21c.

Oracle's "Read-only Oracle home" does not really mean unchangeable, it means that the directory now become a place to store product binaries and patched updates only. All configuration files now go to a new place ORACLE_BASE_HOME.

By default, we derive the value from other variables.

ORACLE_BASE_HOME = <ORACLE_BASE>/homes/<ORACLE_HOME_NAME>

We can also check the value by the command, orabasehome.


[oracle@test ~]$ orabasehome

/u01/app/oracle/homes/OraDB21Home1

In this case, ORACLE_BASE_HOME is at /u01/app/oracle/homes/OraDB21Home1.

The configuration file orabasetab tells more.


[oracle@test ~]$ cat $ORACLE_HOME/install/orabasetab

#orabasetab file is used to track Oracle Home associated with Oracle Base

/u01/app/oracle/product/21.0.0/dbhome_1:/u01/app/oracle:OraDB21Home1:Y:

In the file, there're 4 fields in every entry.

ORACLE_HOME
ORACLE_BASE_HOME
ORACLE_HOME_NAME
"Y" means read-only Oracle home, "N" means the original mode.

To switch back to the original mode (read write) from read-only Oracle home, you need to move all configuration files back to ORACLE_HOME, change the value to N and then restart all database services.

Modify oratab

To startup the database by script, we need to turn N to Y in oratab file.


[oracle@test dbhome_1]$ vi /etc/oratab

...

ORCLCDB:/u01/app/oracle/product/21.0.0/dbhome_1:Y

We have installed a single-instance database 21c. To automatically start the database after system reboot, we have scripts to do it.