Oracle Database Tips by Donald Burleson

Oracle10g Grid Computing with RAC
Chapter 15 - RAC Migration Topics

In Case of Oracle eBusiness Suite

Oracle eBusiness lets us specify or define Oracle Application Object Library profiles with a variety of options. Profile 'Database Instance' allows different responsibilities and users to connect to different nodes of the RAC database sever. The internal name for this profile option is instance_path.

Configuring Virtual IPs For 10g RAC

In order to install or upgrade to Oracle Database 10g RAC, the use of a virtual IP address to mask the individual IPO addresses of the clustered nodes is required. The virtual IP addresses are used to simplify failover and are automatically managed by CRS.

To create a VIP (Virtual IP address), the VIPCA (Virtual IP Configuration Assistant is called from the root.sh script of a RAC install, which then configures the virtual IP addresses for each node specified during the installation process. In order to be able to run VIPCA, there must be unused public IP addresses available for each node that has been configured in the /etc/hosts file.

This means that when installing 10g RAC, at least 3 network interfaces are required for each node in the RAC cluster, these are:

• Public Interface - Used for normal network communications to the node
   

• Virtual (Public) Interface - Used for failover and RAC management
   

• Private Interface - Used as the cluster interconnect

The Oracle 10g RAC installation guide states the following requirements for installing RAC:

• External shared disks. 
   

• One private internet protocol (IP) address for each node to serve as the private cluster interconnect. This IP address must be separate from the public network and it must have the same interface name on every node that is part of your cluster.  This requires its own high speed network interface card (NIC).
   

• One public IP address for each node to use for its Virtual IP address for client connections and for connection failover. This IP address is, in addition to the operating-system, managed public host IP address that is already assigned to the node by the operating system. This public Virtual IP must be associated with the same interface name on every node that is a part of your cluster. Note that, the IP addresses that you use for all of the nodes that are part of a cluster must be from the same subnet. The host names for the VIP addresses must be registered with the domain name server (DNS). The Virtual IP address should not be in use at the time of the installation because this is a Virtual IP address that Oracle manages internally to the RAC processes. This virtual IP address doesn't require a separate NIC.
   

• Redundant switches as a standard configuration for all cluster sizes, however, they will not be checked for.

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