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Oracle Database 12c Release 1 (12.1.) RAC on Oracle Linux 6 Using NFS

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

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 Software

Download the following software.

Operating System Installation

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.

To be consistent with the rest of the article, the following information should be set during the installation.

Node 1.

Node 2.

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.

Oracle Installation Prerequisites

Perform either the Automatic Setup or the Manual Setup to complete the basic prerequisites. The Additional Setup is required for all installations.

Automatic Setup

If you plan to use the "oracle-rdbms-server-12cR1-preinstall" package to perform all your prerequisite setup, issue the following command.

# yum install oracle-rdbms-server-12cR1-preinstall -y
# yum install ntp -y

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.

# yum update -y

Manual Setup

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.

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

Run the following command to change the current kernel parameters.

/sbin/sysctl -p

Add the following lines to the "/etc/security/limits.conf" file.

oracle   soft   nofile    1024
oracle   hard   nofile    65536
oracle   soft   nproc    2047
oracle   hard   nproc    16384
oracle   soft   stack    10240
oracle   hard   stack    32768

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.

# From Public Yum or ULN
yum install binutils -y
yum install compat-libstdc++-33 -y
yum install compat-libstdc++-33.i686 -y
yum install gcc -y
yum install gcc-c++ -y
yum install glibc -y
yum install glibc.i686 -y
yum install glibc-devel -y
yum install glibc-devel.i686 -y
yum install ksh -y
yum install libgcc -y
yum install libgcc.i686 -y
yum install libstdc++ -y
yum install libstdc++.i686 -y
yum install libstdc++-devel -y
yum install libstdc++-devel.i686 -y
yum install libaio -y
yum install libaio.i686 -y
yum install libaio-devel -y
yum install libaio-devel.i686 -y
yum install libXext -y
yum install libXext.i686 -y
yum install libXtst -y
yum install libXtst.i686 -y
yum install libX11 -y
yum install libX11.i686 -y
yum install libXau -y
yum install libXau.i686 -y
yum install libxcb -y
yum install libxcb.i686 -y
yum install libXi -y
yum install libXi.i686 -y
yum install make -y
yum install sysstat -y
yum install unixODBC -y
yum install unixODBC-devel -y
yum install zlib-devel -y
yum install zlib-devel.i686 -y

Create the new groups and users.

groupadd -g 54321 oinstall
groupadd -g 54322 dba
groupadd -g 54323 oper
#groupadd -g 54324 backupdba
#groupadd -g 54325 dgdba
#groupadd -g 54326 kmdba
#groupadd -g 54327 asmdba
#groupadd -g 54328 asmoper
#groupadd -g 54329 asmadmin

useradd -u 54321 -g oinstall -G dba,oper oracle

Uncomment the extra groups you require.

Additional Setup

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.

passwd oracle

Apart form the localhost address, the "/etc/hosts" file can be left blank, but I prefer to put the addresses in for reference.

127.0.0.1       localhost.localdomain   localhost
# Public
192.168.56.201   ol6-121-rac1.localdomain        ol6-121-rac1
192.168.56.202   ol6-121-rac2.localdomain        ol6-121-rac2
# Private
192.168.1.201   ol6-121-rac1-priv.localdomain   ol6-121-rac1-priv
192.168.1.202   ol6-121-rac2-priv.localdomain   ol6-121-rac2-priv
# Virtual
192.168.56.203   ol6-121-rac1-vip.localdomain    ol6-121-rac1-vip
192.168.56.204   ol6-121-rac2-vip.localdomain    ol6-121-rac2-vip
# SCAN
#192.168.56.205   ol6-121-scan.localdomain ol6-121-scan
#192.168.56.206   ol6-121-scan.localdomain ol6-121-scan
#192.168.56.207   ol6-121-scan.localdomain ol6-121-scan
# NAS
192.168.56.1      nas1.localdomain nas1

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.

#domain localdomain
search localdomain
nameserver 192.168.56.1

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.

ONBOOT=no

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.

# ifdown eth0

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.

# ifconfig -a
eth0      Link encap:Ethernet  HWaddr 08:00:27:3D:36:8D  
          inet6 addr: fe80::a00:27ff:fe3d:368d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:76 errors:0 dropped:0 overruns:0 frame:0
          TX packets:88 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:8037 (7.8 KiB)  TX bytes:8429 (8.2 KiB)

eth1      Link encap:Ethernet  HWaddr 08:00:27:29:72:97  
          inet addr:192.168.56.201  Bcast:192.168.56.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe29:7297/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:492 errors:0 dropped:0 overruns:0 frame:0
          TX packets:311 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:45435 (44.3 KiB)  TX bytes:58001 (56.6 KiB)

eth2      Link encap:Ethernet  HWaddr 08:00:27:51:64:36  
          inet addr:192.168.1.201  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe51:6436/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:1128 (1.1 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:4 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:240 (240.0 b)  TX bytes:240 (240.0 b)

#

With this in place and the DNS configured the SCAN address is being resolved to all three IP addresses.

# nslookup ol6-121-scan
Server:		192.168.56.1
Address:	192.168.56.1#53

Name:	ol6-121-scan.localdomain
Address: 192.168.56.205
Name:	ol6-121-scan.localdomain
Address: 192.168.56.206
Name:	ol6-121-scan.localdomain
Address: 192.168.56.207

#

Amend the "/etc/security/limits.d/20-nproc.conf" file as described below. See MOS Note [ID 1487773.1]

# Change this
*          soft    nproc    4096

# To this
* - nproc 16384

Change the setting of SELinux to permissive by editing the "/etc/selinux/config" file, making sure the SELINUX flag is set as follows.

SELINUX=permissive

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.

# service iptables stop
# chkconfig iptables off

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.

# service ntpd stop
Shutting down ntpd:                                        [  OK  ]
# chkconfig ntpd off
# mv /etc/ntp.conf /etc/ntp.conf.orig
# rm /var/run/ntpd.pid

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.

OPTIONS="-x -u ntp:ntp -p /var/run/ntpd.pid"

Then restart NTP.

# service ntpd restart

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.

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

export ORACLE_HOSTNAME=ol6-121-rac1.localdomain
export ORACLE_UNQNAME=CDBRAC
export ORACLE_BASE=/u01/app/oracle
export GRID_HOME=/u01/app/12.1.0.2/grid
export DB_HOME=$ORACLE_BASE/product/12.1.0.2/db_1
export ORACLE_HOME=$DB_HOME
export ORACLE_SID=cdbrac1
export ORACLE_TERM=xterm
export BASE_PATH=/usr/sbin:$PATH
export PATH=$ORACLE_HOME/bin:$BASE_PATH

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

alias grid_env='. /home/oracle/grid_env'
alias db_env='. /home/oracle/db_env'

Create a file called "/home/oracle/grid_env" with the following contents.

export ORACLE_HOME=$GRID_HOME
export PATH=$ORACLE_HOME/bin:$BASE_PATH

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

Create a file called "/home/oracle/db_env" with the following contents.

export ORACLE_SID=cdbrac1
export ORACLE_HOME=$DB_HOME
export PATH=$ORACLE_HOME/bin:$BASE_PATH

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

Once the "/home/oracle/.bash_profile" has been run, you will be able to switch between environments as follows.

$ grid_env
$ echo $ORACLE_HOME
/u01/app/12.1.0.2/grid
$ db_env
$ echo $ORACLE_HOME
/u01/app/oracle/product/12.1.0.2/db_1
$

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.

# shutdown -r now

Create Shared Disks

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.

mkdir /shared_config
mkdir /shared_grid
mkdir /shared_home
mkdir /shared_data

Add the following lines to the "/etc/exports" file.

/shared_config               *(rw,sync,no_wdelay,insecure_locks,no_root_squash)
/shared_grid                 *(rw,sync,no_wdelay,insecure_locks,no_root_squash)
/shared_home                 *(rw,sync,no_wdelay,insecure_locks,no_root_squash)
/shared_data                 *(rw,sync,no_wdelay,insecure_locks,no_root_squash)

Run the following command to export the NFS shares.

chkconfig nfs on
service nfs restart

On both ol6-121-rac1 and ol6-121-rac2 create the directories in which the Oracle software will be installed.

mkdir -p /u01/app/12.1.0.2/grid
mkdir -p /u01/app/oracle/product/12.1.0.2/db_1
mkdir -p /u01/oradata
mkdir -p /u01/shared_config
chown -R oracle:oinstall /u01/app /u01/app/oracle /u01/oradata /u01/shared_config
chmod -R 775 /u01/app /u01/app/oracle /u01/oradata /u01/shared_config

Add the following lines to the "/etc/fstab" file.

nas1:/shared_config /u01/shared_config  nfs  rw,bg,hard,nointr,tcp,vers=3,timeo=600,rsize=32768,wsize=32768,actimeo=0  0 0
nas1:/shared_grid   /u01/app/12.1.0.2/grid  nfs  rw,bg,hard,nointr,tcp,vers=3,timeo=600,rsize=32768,wsize=32768,actimeo=0  0 0
nas1:/shared_home   /u01/app/oracle/product/12.1.0.2/db_1  nfs  rw,bg,hard,nointr,tcp,vers=3,timeo=600,rsize=32768,wsize=32768,actimeo=0  0 0
nas1:/shared_data   /u01/oradata  nfs  rw,bg,hard,nointr,tcp,vers=3,timeo=600,rsize=32768,wsize=32768,actimeo=0  0 0

Mount the NFS shares on both servers.

mount /u01/shared_config
mount /u01/app/12.1.0.2/grid
mount /u01/app/oracle/product/12.1.0.2/db_1
mount /u01/oradata

Make sure the permissions on the shared directories are correct.

chown -R oracle:oinstall /u01/shared_config
chown -R oracle:oinstall /u01/app/12.1.0.2/grid
chown -R oracle:oinstall /u01/app/oracle/product/12.1.0.2/db_1
chown -R oracle:oinstall /u01/oradata

Install the Grid Infrastructure

Start both RAC nodes, login to ol6-121-rac1 as the oracle user and start the Oracle installer.

./runInstaller

Select the "Install and Configure Grid Infrastructure for a Cluster" option, then click the "Next" button.

Grid - Select Installation Option

Select the "Configure a Standard Cluster" option, then click the "Next" button.

Grid - Select Cluster Type

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

Grid - Select Installation Type

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

Grid - Select Product Languages

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

Grid - Grid Plug and Play Information

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

Grid - Cluster Node Information

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

Grid - Add Cluster Node Information

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.

Grid - SSH Connectivity

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

Grid - Specify Network Interface Usage

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

Grid - Storage Option Information

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

Grid - OCR Storage Option

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

Grid - Voting Disk Storage Option

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

Grid - Failure Isolation Support

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

Grid - Specify Management Options

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

Grid - Privileged Operating System Groups

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.

Grid - Specify Install Location

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

Grid - Create Inventory

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

Grid - Root Script Execution Configuration

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.

Grid - Perform Prerequisite Checks

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

Grid - Summary

Wait while the setup takes place.

Grid - Setup

When prompted, run the configuration scripts on each node.

Grid - Execute Configuration Scripts

The output from the "orainstRoot.sh" file should look something like that listed below.

# /u01/app/oraInventory/orainstRoot.sh
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.
#

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.

Grid - Execute Configuration Scripts

Wait for the configuration assistants to complete.

Grid - Configuration Assistants

We expect the verification phase to fail with an error relating to the SCAN, assuming you are not using DNS.

INFO: Checking Single Client Access Name (SCAN)...
INFO: Checking name resolution setup for "rac-scan.localdomain"...
INFO: ERROR:
INFO: PRVF-4664 : Found inconsistent name resolution entries for SCAN name "rac-scan.localdomain"
INFO: ERROR:
INFO: PRVF-4657 : Name resolution setup check for "rac-scan.localdomain" (IP address: 192.168.2.201) failed
INFO: ERROR:
INFO: PRVF-4664 : Found inconsistent name resolution entries for SCAN name "rac-scan.localdomain"
INFO: Verification of SCAN VIP and Listener setup failed

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.

Grid - Finish

The grid infrastructure installation is now complete.

Install the Database

Start all the RAC nodes, login to ol6-121-rac1 as the oracle user and start the Oracle installer.

./runInstaller

Uncheck the security updates checkbox and click the "Next" button.

DB - Configure Security Updates

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

DB - Select Installation Option

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

DB - System Class

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

DB - Grid Installation Options

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

DB - Select Type Of Cluster Database

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

DB - Node Selection

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

DB - Select Install Type

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".

DB - Typical Install Configuration

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.

DB - Perform Prerequisite Checks

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

DB - Summary

Wait while the installation takes place.

DB - Install Product

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

DB - Execute Configuration Scripts

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

DB - DBCA

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

DB - DBCA Complete

Click the "Close" button to exit the installer.

DB - Finish

The RAC database creation is now complete.

Check the Status of the RAC

There are several ways to check the status of the RAC. The srvctl utility shows the current configuration and status of the RAC database.

$ srvctl config database -d cdbrac
Database unique name: cdbrac
Database name: cdbrac
Oracle home: /u01/app/oracle/product/12.1.0.2/db_1
Oracle user: oracle
Spfile: /u01/oradata/cdbrac/spfilecdbrac.ora
Password file: /u01/oradata/cdbrac/orapwcdbrac
Domain: 
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: 
Disk Groups: 
Mount point paths: 
Services: 
Type: RAC
Start concurrency: 
Stop concurrency: 
OSDBA group: dba
OSOPER group: dba
Database instances: cdbrac1,cdbrac2
Configured nodes: ol6-121-rac1,ol6-121-rac2
Database is administrator managed
$

$ srvctl status database -d cdbrac
Instance cdbrac1 is running on node ol6-121-rac1
Instance cdbrac2 is running on node ol6-121-rac2
$

The V$ACTIVE_INSTANCES view can also display the current status of the instances.

$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Mon Sep 28 17:32:56 2015

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP, Advanced Analytics
and Real Application Testing options

SQL> SELECT inst_Name FROM v$active_instances;

INST_NAME
------------------------------------------------------------
ol6-121-rac1.localdomain:cdbrac1
ol6-121-rac2.localdomain:cdbrac2

SQL>

Direct NFS Client

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.

  1. $ORACLE_HOME/dbs/oranfstab
  2. /etc/oranfstab
  3. /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.

srvctl stop database -d cdbrac

# manual method
cd $ORACLE_HOME/lib
mv libodm12.so libodm12.so_stub
ln -s libnfsodm12.so libodm12.so

# make method
$ cd $ORACLE_HOME/rdbms/lib
$ make -f ins_rdbms.mk dnfs_on

srvctl start database -d vdbrac

With the configuration complete, you can see the direct NFS client usage via the following views.

For example.

SQL> SELECT svrname, dirname FROM v$dnfs_servers;

SVRNAME        DIRNAME
-------------  -----------------
nas1           /shared_data

SQL>

The Direct NFS Client supports direct I/O and asynchronous I/O by default.

For more information see:

Hope this helps. Regards Tim...

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