Oracle Rac

Introduction

1.1. Overview of new concepts in 11gR2 Grid Infrastructure

1.1.1. SCAN

The single client access name (SCAN) is the address used by all clients connecting to the cluster. The SCAN

name is a domain name registered to three IP addresses, either in the domain name service (DNS) or the Grid

Naming Service (GNS). The SCAN name eliminates the need to change clients when nodes are added to or

removed from the cluster. Clients using SCAN names can also access the cluster using EZCONNECT.

The Single Client Access Name (SCAN) is a domain name that resolves to all the addresses allocated

for the SCAN name. Three IP addresses should be provided (in DNS) to use for SCAN name mapping

as this ensures high availability. During Oracle Grid Infrastructure installation, listeners are created

for each of the SCAN addresses, and Oracle Grid Infrastructure controls which server responds to a

SCAN address request.

*

* The SCAN addresses need to be on the same subnet as the VIP addresses for nodes in the cluster.

* The SCAN domain name must be unique within your corporate network.

1.1.2. GNS

In the past, the host and VIP names and addresses were defined in the DNS or locally in a hosts file. GNS can

simplify this setup by using DHCP. To use GNS, DHCP must be configured in the subdomain in which the

cluster resides.

1.1.3. OCR and Voting on ASM storage

The ability to use ASM (Automatic Storage Management) diskgroups for Clusterware OCR and Voting disks

is a new feature in the Oracle Database 11g Release 2 Grid Infrastructure. If you choose this option and ASM

is not yet configured, OUI launches ASM configuration assistant to configure ASM and a diskgroup.

1.1.4. Passwordless Automatic SSH Connectivity

If SSH has not been configured prior to the Installation, you can prompt the installer to do this for you. The

configuration can be tested as well.

1.1.5. Intelligent Platform Management interface (IPMI)

Intelligent Platform Management Interface (IPMI) provides a set of common