Step-by-Step Guide: Installing and Configuring Oracle RAC on Oracle 21c

In this comprehensive guide, we’ll walk you through the process of installing and configuring a two-node Oracle Real Application Clusters (RAC) environment using Oracle Database 21c on the latest version of Oracle Linux. We’ll cover everything from hardware requirements and kernel parameters to installing binaries and configuring Automatic Storage Management (ASM).

Table of Contents

Prerequisites

Before you begin, ensure you have the following:

  • Access to two servers running the latest version of Oracle Linux.
  • Oracle Database 21c software (both Grid Infrastructure and Database).
  • Basic understanding of Oracle RAC concepts.

Hardware Requirements

Ensure that both nodes meet the minimum hardware requirements:

  • CPU: At least 2 CPU cores per node.
  • Memory: Minimum 8 GB RAM per node.
  • Storage:
    • At least 15 GB for Oracle Grid Infrastructure binaries.
    • At least 20 GB for Oracle Database binaries.
    • Shared storage for ASM disks.
  • Network: At least two network interfaces per node (one for public network and one for private interconnect).

Network Configuration

Configure the network interfaces on both nodes:

  1. Public Interface: For client connections.
    • Example: eth0
  2. Private Interface: For cluster interconnect.
    • Example: eth1

Ensure that both nodes can resolve each other’s public and private hostnames via /etc/hosts or DNS.

Editing /etc/hosts

192.168.1.101 racnode1.localdomain racnode1 
192.168.1.102 racnode2.localdomain racnode2 
10.0.0.1 racnode1-priv.localdomain racnode1-priv 
10.0.0.2 racnode2-priv.localdomain racnode2-priv

Setting Kernel Parameters

Modify the kernel parameters on both nodes as per Oracle recommendations.

Editing /etc/sysctl.conf

fs.aio-max-nr = 1048576 
fs.file-max = 6815744 
kernel.shmall = 2097152 
kernel.shmmax = 8589934592 
# Set to half of your physical memory 
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 the changes:

# sysctl -p

Setting Shell Limits

Edit /etc/security/limits.conf and add:

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

Creating Users and Groups

Create the necessary OS groups and user:

# groupadd -g 54321 oinstall 
# groupadd -g 54322 dba 
# groupadd -g 54323 asmadmin 
# groupadd -g 54324 asmdba 
# groupadd -g 54325 asmoper 
# useradd -u 54321 -g oinstall -G dba,asmdba,asmadmin,asmoper oracle 
# passwd oracle

Configuring Shared Storage with ASM

Configure shared disks for ASM on both nodes. For this guide, we’ll use udev rules to map the devices.

Identifying Shared Disks

Assuming the shared disks are /dev/sdb and /dev/sdc.

Setting Up Udev Rules

Create udev rules in /etc/udev/rules.d/99-oracle-asm.rules:

KERNEL=="sd[b-c]", OWNER="oracle", GROUP="asmadmin", MODE="0660"

Reload udev rules:

# udevadm control --reload-rules 
# udevadm trigger

Installing Oracle Grid Infrastructure

As the oracle user, perform the following steps:

Setting Up Environment Variables

$ vi ~/.bash_profile
Add the following lines
export ORACLE_BASE=/u01/app/oracle 
export ORACLE_HOME=/u01/app/21.0.0/grid 
export PATH=$PATH:$ORACLE_HOME/bin

Running the Installer

  1. Unzip the Grid Infrastructure software: 
    $ unzip linuxx64_21_grid_home.zip -d $ORACLE_HOME
  2. Start the installer: 
    $ $ORACLE_HOME/gridSetup.sh

Installer Steps

  • Select Configure Oracle Grid Infrastructure for a New Cluster.
Configure Oracle Grid Infrastructure for a New Cluster
Configure Oracle Grid Infrastructure for a New Cluster
  • Provide cluster name and SCAN details.
  • Add both nodes to the cluster configuration.
  • Select Use Standard ASM for storage.
  • Specify ASM passwords and disk groups.
  • Complete the installation and run the root scripts when prompted.

Installing Oracle Database Software

As the oracle user, proceed with the database installation.

Running the Installer

  1. Unzip the Database software: 
    $ unzip LINUX.X64_213000_db_home.zip -d $ORACLE_BASE/product/21.0.0/dbhome_1
  2. Start the installer: 
    $ $ORACLE_BASE/product/21.0.0/dbhome_1/runInstaller

Installer Steps

  1. Choose Install database software only.
  2. Select Oracle Real Application Clusters database installation.
  3. Select both nodes for installation.
  4. Choose Enterprise Edition.
  5. Specify the Oracle base and software locations.
  6. Run root scripts when prompted.

Creating a RAC Database

After installing the software, create a RAC database using the Database Configuration Assistant (DBCA).

Running DBCA

$ dbca

DBCA Steps

  1. Select Create a database.
  2. Choose Oracle Real Application Clusters (RAC) database.
  3. Select both nodes for the database instances.
  4. Choose Advanced configuration.
  5. Configure database options as required.
  6. Select ASM as the storage option and choose the disk groups.
  7. Complete the database creation.

Post-Installation Tasks

Perform the following tasks to finalize the setup:

Setting Environment Variables

Update the ~/.bash_profile:

export ORACLE_SID=orcl 
export ORACLE_HOME=/u01/app/oracle/product/21.0.0/dbhome_1 
export PATH=$PATH:$ORACLE_HOME/bin

Verifying the RAC Status

$ srvctl status database -d orcl

Conclusion

You have successfully installed and configured a two-node Oracle RAC environment on Oracle 21c using Oracle Linux.

This setup allows for high availability and scalability for your Oracle databases.

References

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