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Oracle Database 11g Release 2 RAC On Linux Using NFS

This article describes the installation of Oracle Database 11g Release 2 (11.2 64-bit) RAC on Linux (Oracle Enterprise Linux 5.4 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.

To cut costs, this articles uses one of the RAC nodes as the source of the shared storage. Obviously, this means if that node goes down the whole database is lost, so it's not a sensible idea to do this if you are testing high availability. If you have access to a NAS or a third server you can easily use that for the shared storage, making the whole solution much more resilient. 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. In this article I've defined it as a single IP address in the "/etc/hosts" file, which is wrong and will cause the cluster verification to fail, but it allows me to complete the install without the presence of a DNS.

This article was inspired by the blog postings of Kevin Closson.

Download Software

Download the following software.

Operating System Installation

This article uses Oracle Enterprise Linux 5.4. 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 and secure Linux disabled. 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.

RAC1.

RAC2.

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.

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-validated" package to perform all your prerequisite setup, follow the instructions at http://public-yum.oracle.com to setup the yum repository for OL, then perform the following command.

# yum install oracle-validated

All necessary prerequisites will be performed automatically.

It is probably worth doing a full update as well, but this is not strictly speaking necessary.

# yum update

Manual Setup

If you have not used the "oracle-validated" package to perform all prerequisites, you will need to manually perform the following setup tasks.

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 Oracle Linux 5 DVD
cd /media/cdrom/Server
rpm -Uvh binutils-2.*
rpm -Uvh compat-libstdc++-33*
rpm -Uvh elfutils-libelf-0.*
rpm -Uvh elfutils-libelf-devel-*
rpm -Uvh gcc-4.*
rpm -Uvh gcc-c++-4.*
rpm -Uvh glibc-2.*
rpm -Uvh glibc-common-2.*
rpm -Uvh glibc-devel-2.*
rpm -Uvh glibc-headers-2.*
rpm -Uvh ksh-2*
rpm -Uvh libaio-0.*
rpm -Uvh libaio-devel-0.*
rpm -Uvh libgcc-4.*
rpm -Uvh libstdc++-4.*
rpm -Uvh libstdc++-devel-4.*
rpm -Uvh make-3.*
rpm -Uvh sysstat-7.*
rpm -Uvh unixODBC-2.*
rpm -Uvh unixODBC-devel-2.*

cd /
eject

Add or amend the following lines to the "/etc/sysctl.conf" file.

fs.aio-max-nr = 1048576
fs.file-max = 6815744
kernel.shmall = 2097152
kernel.shmmax = 1054504960
kernel.shmmni = 4096
# semaphores: semmsl, semmns, semopm, semmni
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=1048586

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    nproc   2047
oracle               hard    nproc   16384
oracle               soft    nofile  1024
oracle               hard    nofile  65536

Add the following lines to the "/etc/pam.d/login" file, if it does not already exist.

session    required     pam_limits.so

Create the new groups and users.

groupadd -g 1000 oinstall
groupadd -g 1200 dba
useradd -u 1100 -g oinstall -G dba oracle
passwd oracle

Create the directories in which the Oracle software will be installed.

mkdir -p  /u01/app/11.2.0/grid
mkdir -p /u01/app/oracle/product/11.2.0/db_1
chown -R oracle:oinstall /u01
chmod -R 775 /u01/

Additional Setup

Perform the following steps whilst logged into the "ol5-112-rac1" virtual machine as the root user.

Set the password for the "oracle" user.

passwd oracle

Install the following package from the Oracle grid media after you've defined groups.

cd /your/path/to/grid/rpm
rpm -Uvh cvuqdisk*

If you are not using DNS, the "/etc/hosts" file must contain the following information.

127.0.0.1       localhost.localdomain   localhost
# Public
192.168.0.101   ol5-112-rac1.localdomain        ol5-112-rac1
192.168.0.102   ol5-112-rac2.localdomain        ol5-112-rac2
# Private
192.168.1.101   ol5-112-rac1-priv.localdomain   ol5-112-rac1-priv
192.168.1.102   ol5-112-rac2-priv.localdomain   ol5-112-rac2-priv
# Virtual
192.168.0.103   ol5-112-rac1-vip.localdomain    ol5-112-rac1-vip
192.168.0.104   ol5-112-rac2-vip.localdomain    ol5-112-rac2-vip
# SCAN
192.168.0.105   ol5-112-scan.localdomain        ol5-112-scan
192.168.0.106   ol5-112-scan.localdomain        ol5-112-scan
192.168.0.107   ol5-112-scan.localdomain        ol5-112-scan

Note. The SCAN address should not really be defined in the hosts file. Instead is should be defined on the DNS to round-robin between 3 addresses on the same subnet as the public IPs. For this installation, we will compromise and use the hosts file. This may cause problems if you are using 11.2.0.2 onward.

If you are using DNS, then only the first line needs to be present in the "/etc/hosts" file. The other entries are defined in the DNS, as described here. Having said that, I typically include all but the SCAN addresses.

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

Alternatively, this alteration can be done using the GUI tool (System > Administration > Security Level and Firewall). Click on the SELinux tab and disable the feature.

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.

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

If 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

Create the directories in which the Oracle software will be installed.

mkdir -p  /u01/app/11.2.0/grid
mkdir -p /u01/app/oracle/product/11.2.0/db_1
chown -R oracle:oinstall /u01
chmod -R 775 /u01/

Login as the "oracle" user and add the following lines at the end of the "/home/oracle/.bash_profile" file.

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

ORACLE_HOSTNAME=ol5-112-rac1.localdomain; export ORACLE_HOSTNAME
ORACLE_UNQNAME=RAC; export ORACLE_UNQNAME
ORACLE_BASE=/u01/app/oracle; export ORACLE_BASE
GRID_HOME=/u01/app/11.2.0/grid; export GRID_HOME
DB_HOME=$ORACLE_BASE/product/11.2.0/db_1; export DB_HOME
ORACLE_HOME=$DB_HOME; export ORACLE_HOME
ORACLE_SID=RAC1; export ORACLE_SID
ORACLE_TERM=xterm; export ORACLE_TERM
BASE_PATH=/usr/sbin:$PATH; export BASE_PATH
PATH=$ORACLE_HOME/bin:$BASE_PATH; export PATH

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

if [ $USER = "oracle" ]; then
  if [ $SHELL = "/bin/ksh" ]; then
    ulimit -p 16384
    ulimit -n 65536
  else
    ulimit -u 16384 -n 65536
  fi
fi

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.

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

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

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

ORACLE_SID=RAC1; export ORACLE_SID
ORACLE_HOME=$DB_HOME; export ORACLE_HOME
PATH=$ORACLE_HOME/bin:$BASE_PATH; export PATH

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

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

$ grid_env
$ echo $ORACLE_HOME
/u01/app/11.2.0/grid
$ db_env
$ echo $ORACLE_HOME
/u01/app/oracle/product/11.2.0/db_1
$

Remember to amend the environment setting accordingly on each server.

We've made a lot of changes, so it's worth doing a reboot of the servers 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 this on the RAC1 node, but you can do the on a NAS or a third server if you have one available. On the RAC1 node 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 RAC1 and RAC2 create the directories in which the Oracle software will be installed.

mkdir -p /u01/app/11.2.0/grid
mkdir -p /u01/app/oracle/product/11.2.0/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/11.2.0/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/11.2.0/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/11.2.0/grid
mount /u01/app/oracle/product/11.2.0/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/11.2.0/grid
chown -R oracle:oinstall /u01/app/oracle/product/11.2.0/db_1
chown -R oracle:oinstall /u01/oradata

Install the Grid Infrastructure

Start both RAC nodes, login to 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 "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 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

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/11.2.0/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

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 "Finish" 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.

# cd /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 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 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

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 Istall Type

Enter "/u01/app/oracle/product/11.2.0/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 "RAC.localdomain".

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 "Finish" button.

DB - Summary

Wait while the installation takes place.

DB - Install Product

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

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

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 rac
Database unique name: rac
Database name: rac
Oracle home: /u01/app/oracle/product/11.2.0/db_1
Oracle user: oracle
Spfile: /u01/oradata/rac/spfilerac.ora
Domain: localdomain
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools: rac
Database instances: rac1,rac2
Disk Groups: 
Services: 
Database is administrator managed
$

$ srvctl status database -d rac
Instance rac1 is running on node rac1
Instance rac2 is running on node rac2
$

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

$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Sat Sep 26 19:04:19 2009

Copyright (c) 1982, 2009, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options

SQL> SELECT inst_name FROM v$active_instances;

INST_NAME
--------------------------------------------------------------------------------
rac1.localdomain:rac1
rac2.localdomain:rac2

SQL>

If you have configured Enterprise Manager, it can be used to view the configuration and current status of the database using a URL like "https://rac1.localdomain:1158/em".

OEM

Direct NFS Client

For improved NFS performance, Oracle recommend using the Direct NFS Client shipped with Oracle 11g. 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 "libodm11.so" library for the "libnfsodm11.so" library, which can be done manually or via the "make" command.

srvctl stop database -d rac

# manual method
cd $ORACLE_HOME/lib
mv libodm11.so libodm11.so_stub
ln -s libnfsodm11.so libodm11.so

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

srvctl start database -d rac

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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