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.

• Oracle Enterprise Linux 5.4
• Oracle 11g Release 2 (11.2) Clusterware and Database 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:

• GNOME Desktop Environment
• Editors
• Graphical Internet
• Text-based Internet
• Development Libraries
• Development Tools
• Server Configuration Tools
• Administration Tools
• Base
• System Tools
• X Window System

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

RAC1:

• hostname: rac1.localdomain
• IP Address eth0: 192.168.2.101 (public address)
• Default Gateway eth0: 192.168.2.1 (public address)
• IP Address eth1: 192.168.0.101 (private address)
• Default Gateway eth1: none

RAC2:

• hostname: rac2.localdomain
• IP Address eth0: 192.168.2.102 (public address)
• Default Gateway eth0: 192.168.2.1 (public address)
• IP Address eth1: 192.168.0.102 (private address)
• Default Gateway eth1: none

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.

Once the basic installation is complete, install the following packages whilst logged in as the root user. This includes the 64-bit and 32-bit versions of some packages.

# From Enterprise 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

Oracle Installation Prerequisites

Perform the following steps whilst logged into the RAC1 virtual machine as the root user.

Make sure the shared memory filesystem is big enough for Automatic Memory Manager to work.

# umount tmpfs

# mount -t tmpfs shmfs -o size=1500m /dev/shm

Make the setting permanent by amending the "tmpfs" setting of the "/etc/fstab" file to look like this.

tmpfs                   /dev/shm                tmpfs   size=1500m      0 0

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

127.0.0.1       localhost.localdomain   localhost

# Public

192.168.2.101   rac1.localdomain        rac1

192.168.2.102   rac2.localdomain        rac2

#Private

192.168.0.101   rac1-priv.localdomain   rac1-priv

192.168.0.102   rac2-priv.localdomain   rac2-priv

#Virtual

192.168.2.111   rac1-vip.localdomain    rac1-vip

192.168.2.112   rac2-vip.localdomain    rac2-vip

# SCAN

192.168.2.201   rac-scan.localdomain    rac-scan

#NAS

192.168.2.101   nas1.localdomain        nas1

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. If you are using DNS, then only the first line should be present in the "/etc/hosts" file. The other entries are defined in the DNS, as described here. Also, the NAS1 entry is actually pointing to the RAC1 node. If you are using a real NAS or a third server to provide your shared storage put the correct IP address into the file.

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 = 536870912

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

Disable secure linux by editing the "/etc/selinux/config" file, making sure the SELINUX flag is set as follows.

SELINUX=disabled

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.

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. In this case we will deconfigure NTP.

# service ntpd stop

Shutting down ntpd:                                        [  OK  ]

# chkconfig ntpd off

# mv /etc/ntp.conf /etc/ntp.conf.org

# rm /var/run/ntpd.pid

If you are using 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

Start the Name Service Cache Daemon (nscd).

chkconfig --level 35 nscd on

service nscd start

Create the new groups and users.

groupadd -g 1000 oinstall

groupadd -g 1200 dba

useradd -u 1100 -g oinstall -G dba oracle

passwd oracle

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

# Oracle Settings

TMP=/tmp; export TMP

TMPDIR=$TMP; export TMPDIR

ORACLE_HOSTNAME=rac1.localdomain; export ORACLE_HOSTNAME

ORACLE_UNQNAME=rac; export ORACLE_UNQNAME

ORACLE_BASE=/u01/app/oracle; export ORACLE_BASE

ORACLE_HOME=$ORACLE_BASE/product/11.2.0/db_1; export ORACLE_HOME

ORACLE_SID=rac1; export ORACLE_SID

ORACLE_TERM=xterm; export ORACLE_TERM

PATH=/usr/sbin:$PATH; export PATH

PATH=$ORACLE_HOME/bin:$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

Remember to amend the ORACLE_SID and ORACLE_HOSTNAME on each server.

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.



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 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.



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/11.2.0/grid" as the software location, then click the "Next" button.



Accept the default inventory directory by clicking 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 "Finish" 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.

# 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.



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.

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.



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.



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



Accept the "Server Class" option by clicking 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/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".



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 "Finish" button.



Wait while the installation takes place.



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.



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



Click the "Close" button to exit the installer.



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".

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, as shown below.

srvctl stop database -d rac

cd $ORACLE_HOME/lib

mv libodm11.so libodm11.so_stub

ln -s libnfsodm11.so libodm11.so

srvctl start database -d rac

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:

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.