This article describes the installation of Oracle Database 12c Release 2 (12.1 64-bit) RAC on Oracle Linux 6.7 64-bit using NFS to provide the shared storage. - Introduction - Download Software - Operating System Installation - Oracle Installation Prerequisites Automatic Setup Manual Setup Additional Setup - Automatic Setup - Manual Setup - Additional Setup - Create Shared Disks - Install the Grid Infrastructure - Install the Database - Check the Status of the RAC - Direct NFS Client - Automatic Setup - Manual Setup - Additional Setup NFS is an abbreviation of Network File System, a platform independent technology created by Sun Microsystems that allows shared access to files stored on computers via an interface called the Virtual File System (VFS) that runs on top of TCP/IP. Computers that share files are considered NFS servers, while those that access shared files are considered NFS clients. An individual computer can be either an NFS server, a NFS client or both. We can use NFS to provide shared storage for a RAC installation. In a production environment we would expect the NFS server to be a NAS, but for testing it can just as easily be another server, or even one of the RAC nodes itself. In this case, I'm doing the installations on VirtualBox VMs and the NFS shares are on the host server. If you have access to a NAS or a third server you can easily use that for the shared storage. Whichever route you take, the fundamentals of the installation are the same. The Single Client Access Name (SCAN) should really be defined in the DNS or GNS and round-robin between one of 3 addresses, which are on the same subnet as the public and virtual IPs. You can try to use a single IP address in the "/etc/hosts" file, which it will cause the cluster verification to fail, but it allows me to complete the install without the presence of a DNS. Assumptions. You need two machines available to act as your two RAC nodes. They can be physical or virtual. In this case I'm using two virtual machines called "ol6-121-rac1" and "ol6-121-rac2". If you want a different naming convention or different IP addresses that's fine, but make sure you stay consistent with how they are used. Download the following software. This article uses Oracle Linux 6.7. A general pictorial guide to the operating system installation can be found here . More specifically, it should be a server installation with a minimum of 2G swap (preferably 3-4G), firewall disabled and SELinux set to permissive. Oracle recommend a default server installation, but if you perform a custom installation include the following package groups. - Base System > Base - Base System > Compatibility Libraries - Base System > Large Systems Performance - Base System > Network Files System Client - Base System > Perl Support - Servers > Server Platform - Servers > System Administration Tools - Desktops > Desktop - Desktops > Desktop Debugging and Performance Tools - Desktops > Desktop Platform - Desktops > Fonts - Desktops > General Purpose Desktop - Desktops > Graphical Administration Tools - Desktops > Input Methods - Desktops > Legacy X Windows System Compatibility - Desktops > Remote Desktop Clients - Desktops > X Window System - Applications > Internet Browser - Development > Additional Development - Development > Development Tools - UEK3 Kernel Repo > UEK3 Kernel Repo To be consistent with the rest of the article, the following information should be set during the installation. Node 1. - hostname: ol6-121-rac1.localdomain - eth0: DHCP (Connect Automatically) - eth1: IP=192.168.56.201, Subnet=255.255.255.0, Gateway=192.168.56.1, DNS=192.168.56.1, Search=localdomain (Connect Automatically) - eth2: IP=192.168.1.201, Subnet=255.255.255.0, Gateway=<blank>, DNS=<blank>, Search=<blank> (Connect Automatically) Node 2. - hostname: ol6-121-rac2.localdomain - eth0: DHCP (Connect Automatically) - eth1: IP=192.168.56.202, Subnet=255.255.255.0, Gateway=192.168.56.1, DNS=192.168.56.1, Search=localdomain (Connect Automatically) - eth2: IP=192.168.1.202, Subnet=255.255.255.0, Gateway=<blank>, DNS=<blank>, Search=<blank> (Connect Automatically) You are free to change the IP addresses to suit your network, but remember to stay consistent with those adjustments throughout the rest of the article. In this article, I performed the installation using VirtualBox virtual machines, so I also configured a NAT adapter on each machine to allow access to the internet. If you are using physical machines, or virtual machines with direct access to the internet over the public network, like bridged connections, this extra adapter will not be necessary, so ignore the references to it. Perform either the Automatic Setup or the Manual Setup to complete the basic prerequisites. The Additional Setup is required for all installations. If you plan to use the "oracle-rdbms-server-12cR1-preinstall" package to perform all your prerequisite setup, issue the following command. Earlier versions of Oracle Linux required manual setup of the Yum repository by following the instructions at http://public-yum.oracle.com . It is probably worth doing a full update as well, but this is not strictly speaking necessary. If you have not used the "oracle-rdbms-server-12cR1-preinstall" package to perform all prerequisites, you will need to manually perform the following setup tasks. Add or amend the following lines to the "/etc/sysctl.conf" file. Run the following command to change the current kernel parameters. Add the following lines to the "/etc/security/limits.conf" file. In addition to the basic OS installation, the following packages must be installed whilst logged in as the root user. This includes the 64-bit and 32-bit versions of some packages. Create the new groups and users. Uncomment the extra groups you require. The following steps must be performed, whether you did the manual or automatic setup. Perform the following steps whilst logged into the "ol6-121-rac1" virtual machine as the root user. Set the password for the "oracle" user. Apart form the localhost address, the "/etc/hosts" file can be left blank, but I prefer to put the addresses in for reference. The SCAN address is commented out of the hosts file because it must be resolved using a DNS, so it can round-robin between 3 addresses on the same subnet as the public IPs. The DNS can be configured on the host machine using BIND or Dnsmasq , which is much simpler. If you are using Dnsmasq, put the RAC-specific entries in the hosts machines "/etc/hosts" file, with the SCAN entries uncommented, and restart Dnsmasq. Make sure the "/etc/resolv.conf" file includes a nameserver entry that points to the correct nameserver. Also, if the "domain" and "search" entries are both present, comment out one of them. For this installation my "/etc/resolv.conf" looked like this. If you are doing this installation on a virtual machine and you've configured a NAT interface, you might find the changes to the "resolv.conf" will be overwritten by the network manager. For this reason, this interface should now be disabled on startup. You can enable it manually if you need to access the internet from the VMs. Edit config file associated with the NAT network adapter, in this case the "/etc/sysconfig/network-scripts/ifcfg-eth0 file, making the following change. This will take effect after the next restart. There is no need to do the restart now. You can just run the following command. Remember to amend the adapter name if yours are named differently. At this point, the networking for the first node should look something like the following. Notice that eth0, my NAT adapter, has no associated IP address because it is disabled. If you are not using a VM and only configured two network adapters, you will not see this. With this in place and the DNS configured the SCAN address is being resolved to all three IP addresses. Amend the "/etc/security/limits.d/20-nproc.conf" file as described below. See MOS Note [ID 1487773.1] Change the setting of SELinux to permissive by editing the "/etc/selinux/config" file, making sure the SELINUX flag is set as follows. If you have the Linux firewall enabled, you will need to disable or configure it, as shown here or here . The following is an example of disabling the firewall. Either configure NTP, or make sure it is not configured so the Oracle Cluster Time Synchronization Service (ctssd) can synchronize the times of the RAC nodes. If you want to deconfigure NTP do the following, which is what I did for this installation. If your RAC is going to be permanently connected to your main network and you want to use NTP, you must add the "-x" option into the following line in the "/etc/sysconfig/ntpd" file. Then restart NTP. Log in as the "oracle" user and add the following lines at the end of the "/home/oracle/.bash_profile" file. Remember to set the hostnames and ORACLE_SID values correctly in the following scripts. Node 2 will use ol6-121-rac2 and cdbrac2. Create a file called "/home/oracle/grid_env" with the following contents. Create a file called "/home/oracle/db_env" with the following contents. Once the "/home/oracle/.bash_profile" has been run, you will be able to switch between environments as follows. We've made a lot of changes, so it's worth doing a reboot of the machines at this point to make sure all the changes have taken effect. First we need to set up some NFS shares. In this case we will do on the host machine, but you can do the on a NAS or a third server if you have one available. Create the following directories. Add the following lines to the "/etc/exports" file. Run the following command to export the NFS shares. On both ol6-121-rac1 and ol6-121-rac2 create the directories in which the Oracle software will be installed. Add the following lines to the "/etc/fstab" file. Mount the NFS shares on both servers. Make sure the permissions on the shared directories are correct. Start both RAC nodes, login to ol6-121-rac1 as the oracle user and start the Oracle installer. Select the "Install and Configure Grid Infrastructure for a Cluster" option, then click the "Next" button. Select the "Configure a Standard Cluster" option, then click the "Next" button.

Select the "Advanced Installation" option, then click the "Next" button.

Select the the required language support, then click the "Next" button.

Enter cluster information and uncheck the "Configure GNS" option, then click the "Next" button.

On the "Specify Node Information" screen, click the "Add" button.

Enter the details of the second node in the cluster, then click the "OK" button.

Click the "SSH Connectivity..." button and enter the password for the "oracle" user. Click the "Setup" button to configure SSH connectivity, and the "Test" button to test it once it is complete. Click the "Next" button.

Check the public and private networks are specified correctly, then click the "Next" button.

Select the "Shared File System" option, then click the "Next" button.

Select the required level of redundancy and enter the OCR File Location(s), then click the "Next" button.

Select the required level of redundancy and enter the Voting Disk File Location(s), then click the "Next" button.

Accept the default failure isolation support by clicking the "Next" button.

Don't register with Cloud Control. Click the "Next" button.

Select the preferred OS groups for each option, then click the "Next" button. Click the "Yes" button on the subsequent message dialog.

Enter "/u01/app/oracle" as the Oracle Base and "/u01/app/12.1.0.2/grid" as the software location, then click the "Next" button.

Accept the default inventory directory by clicking the "Next" button.

Ignore the root configuration, we will run the scripts manually. Click the "Next" button.

Wait while the prerequisite checks complete. If you have any issues, either fix them or check the "Ignore All" checkbox and click the "Next" button. If there are no issues, you will move directly to the summary screen.

If you are happy with the summary information, click the "Install" button.

Wait while the setup takes place.

When prompted, run the configuration scripts on each node.

The output from the "orainstRoot.sh" file should look something like that listed below. The output of the root.sh will vary a little depending on the node it is run on. Example output can be seen here ( Node1 , Node2 ). Once the scripts have completed, return to the "Execute Configuration Scripts" screen on ol6-121-rac1 and click the "OK" button.

Wait for the configuration assistants to complete.

We expect the verification phase to fail with an error relating to the SCAN, assuming you are not using DNS. Provided this is the only error, it is safe to ignore this and continue by clicking the "Next" button. Click the "Close" button to exit the installer.

The grid infrastructure installation is now complete. Start all the RAC nodes, login to ol6-121-rac1 as the oracle user and start the Oracle installer. Uncheck the security updates checkbox and click the "Next" button.

Accept the "Create and configure a database" option by clicking the "Next" button.

Accept the "Server Class" option by clicking the "Next" button.

Select the "Oracle Real Application Clusters database installation" option, then click the "Next" button.

Select the "Admin managed" option, then click the "Next" button.

Make sure both nodes are selected, then click the "Next" button.

Accept the "Typical install" option by clicking the "Next" button.

Enter "/u01/app/oracle/product/12.1.0.2/db_1" for the software location. The storage type should be set to "File System" with the file location set to "/u01/oradata". Enter the appropriate passwords and database name, in this case "cdbrac".

Wait for the prerequisite check to complete. If there are any problems either fix them, or check the "Ignore All" checkbox and click the "Next" button.

If you are happy with the summary information, click the "Install" button.

Wait while the installation takes place.

When prompted, run the configuration scripts on each node. When the scripts have been run on each node, click the "OK" button.

Once the software installation is complete the Database Configuration Assistant (DBCA) will start automatically.

Once the Database Configuration Assistant (DBCA) has finished, click the "OK" button.

Click the "Close" button to exit the installer.

The RAC database creation is now complete. There are several ways to check the status of the RAC. The utility shows the current configuration and status of the RAC database. The view can also display the current status of the instances. The Direct NFS Client should be used for CRS-related files, so it is important to have separate NFS mounts for the different types of files, rather than trying to compact them into a single NFS share. For improved NFS performance, Oracle recommend using the Direct NFS Client shipped with Oracle 12c. The direct NFS client looks for NFS details in the following locations. - $ORACLE_HOME/dbs/oranfstab - /etc/oranfstab - /etc/mtab Since we already have our NFS mount point details in the "/etc/fstab", and therefore the "/etc/mtab" file also, there is no need to configure any extra connection details. For the client to work we need to switch the "libodm12.so" library for the "libnfsodm12.so" library, which can be done manually or via the "make" command. With the configuration complete, you can see the direct NFS client usage via the following views. - v$dnfs_servers - v$dnfs_files - v$dnfs_channels - v$dnfs_stats For example. The Direct NFS Client supports direct I/O and asynchronous I/O by default. For more information see: Hope this helps. Regards Tim...