Moving to Oracle RAC One Node - Page 2

1. Preliminary Installation

This section lists the setup necessary before starting the Grid Infrastructure software installation.

Software and Hardware requirements

Review the software and hardware requirements listed here. Like in previous versions, the installer does a prerequisite checks before the software installation. New in 11g Release 2 is the installer now offers the ability to generate a Fixup script to fix kernel parameters.

SCAN (Single Client Access Name)

SCAN is new in Oracle 11g Release 2. It simplifies client management by providing a single point of access for clients to connect to any database in the cluster. In the event when nodes were added or removed from the cluster, clients that use SCAN to access the cluster do not have to make any explicit changes to the client settings. This is particularly beneficial for RAC One Node where databases can be configured to relocate to any available nodes.

SCAN is resolvable by either of the following methods:

1.  Domain Name Service (DNS): At least one IP address has to be defined in DNS for the SCAN. The recommended approach is to create a round robin SCAN resolvable to a maximum of three different addresses for high availability and scalability.

2.  Grid Naming Service (GNS): Three IP addresses are automatically acquired from the DHCP service and the GNS provides name resolution for the SCAN.

SCAN addresses, virtual IP addresses, and public IP addresses must all be on the same subnet.

Refer to the following whitepaper for additional information on SCAN.

In this installment, we will use GNS to resolve the SCAN addresses.

Configure GNS (Grid Naming Service) Virtual IP Address

The Grid Naming Service (GNS) is a part of the Grid Plug and Play feature (GPnP), which allows the Oracle Clusterware to dynamically allocate virtual IP addresses for each node through DHCP service running on the public network. All name resolution requests for the cluster within a subdomain delegated by the DNS are handed off to GNS using multicast Domain Name Service (mDNS) included within the Oracle Clusterware. Using GNS eliminates the need for managing IP addresses and name resolution and is especially advantageous in a dynamic cluster environment where nodes are often added or removed.

Prior to the Grid Infrastructure software installation, we have configured a static IP address for the GNS virtual IP and defined gurnard.vcconsult.com as the subdomain to delegate in DNS.

Refer to the Oracle Grid Infrastructure Installation Guide for additional information about GNS.

Configure Oracle ASM (Automatic Storage Management) shared storage

In our environment, we have created four ASM disks; three of which were dedicated for storing the OCR, Voting disk, datafiles and online redo logs and one for the Fast Recovery Area.

[root@gurnard1 ~]# oracleasm listdisks
VOL1
VOL2
VOL3
VOL4
 
[root@gurnard2 ~]# oracleasm listdisks
VOL1
VOL2
VOL3
VOL4

Oracle ASM storage configuration is described here.

CTSS (Cluster Time Synchronization Service)

CTSS is configured automatically as a part of the Grid Infrastructure installation to synchronize the clocks on all the nodes. As an alternative, you can manually configure NTP (Network Time Protocol) on both nodes. We will synchronize the time across the cluster nodes using CTSS.

2. Install Oracle Database 11g Release 2 Grid Infrastructure software

The Grid Infrastructure software now installs both the Oracle Clusterware and ASM into the same Oracle Home. We will use the grid Unix account to install the software.

Download and unzip the software to a staging area and as the grid user on gurnard1, execute runInstaller to start the installation.

grid@gurnard1-> id
uid=1100(grid) gid=1000(oinstall) groups=1000(oinstall),1100(asmadmin),1300(asmdba)
 
grid@gurnard1-> more .profile
export ORACLE_SID=+ASM1
export EDITOR=vi
export ORACLE_BASE=/u01/app/grid
export ORACLE_HOME=/u01/app/11.2.0/grid
export LD_LIBRARY_PATH=$ORACLE_HOME/lib
export PATH=$ORACLE_HOME/bin:/bin:/usr/bin:/usr/sbin:/usr/local/bin
umask 022
            grid@gurnard1-> /software/11gR2x64/grid/runInstaller

1.  Select Installation Option: Click on Install and Configure Grid Infrastructure for a Cluster.

2.  Select Installation Type: Click on Advance Installation.

3.  Select Product Languages: Select English.

4.  Grid Plug and Play Information:

5.  Cluster Node Information:

6.  Specify Network Interface Usage:

7.  Storage Option Information: Select Automatic Storage Management (ASM).

8.  Create ASM Disk Group:

Oracle Clusterware files are stored in the DATA disk group. The disk group redundancy level determines the type of default file mirroring by Oracle ASM:

• External redundancy: no mirroring
• Normal redundancy: 2-way mirroring
• High redundancy: 3-way mirroring