Sunday, April 24, 2011

Network Requirements or configuration for Oracle RAC

Network Requirements or configuration for Oracle RAC

Check that you have the networking hardware and internet protocol (IP) addresses required for an Oracle Real Application Clusters installation.

The two nodes in the cluster must be able to communicate with each other and with external clients using the TCP/IP protocol. Communication between clients and the nodes in the cluster is across the public network. Both nodes need a network adapter configured for the public network.

To enable availability and failover, a virtual IP (VIP) address is also required for each of your nodes. A VIP address can be moved between nodes in case of a failure. CRS manages the VIP addresses for you.

To support a virtual IP address, both nodes require an unused IP address that is compatible with the public network's subnet and netmask. The virtual IP address and host name should also be registered in the domain name system (DNS).

For communications between the instances running on the two nodes, a private network is required. This private network connects only the nodes in the cluster and cannot be accessed from outside the cluster. Both nodes need a separate network adapter configured for this private network.

Specifically, both nodes must meet the following public and private network requirements:

  • Support two network adapters: one for the public network interface, used for client connections, and one for the private network interfaces, used for communication between the database instances.

  • The following describes the naming restrictions for the public and private network interface names:

    • The characters used for the names are case sensitive

    • The names must not contain any multibyte language characters

    • The public and private network interface names must be different from each other

    • The name for each interface must be the same on both nodes

    • The public and private IP addresses must be on different subnets

  • The public network interface must have an IP address and host name registered in the domain name system (DNS)

  • Each private network interface must have a private IP address and may, optionally, have a private host name. Oracle recommends that you use private network IP addresses for these interfaces, for example: 10.*.*.* or 192.168.*.*. You can use the %SystemRoot%\system32\drivers\etc\hosts file on both nodes to associate private host names with private IP addresses.

For example, in a two node cluster, you might have the following host names and IP addresses:

Host Name Type IP Address Registered In Public

DNS Public

DNS Virtual

DNS Virtual

rac1-priv Private

rac2-priv Private


As you perform the following steps, you may wish to add your own values to the preceding table for easy reference when completing the installation dialogs.

To configure or determine the IP addresses associated with your cluster nodes, perform the following steps:

  1. Determine the IP addresses and names for the two public and two virtual IP addresses that you will be using. These names and IP addresses should be registered with your DNS. You will also need to know the IP address of your DNS server during the installation: you may want to add it to the values that you record in the preceding table.

  2. If your nodes already contain network adapters with IP addresses, you can retrieve the public addresses by entering the ipconfig command in a Command window.

  3. If necessary, install the network adapters for the public and private networks and configure one of them with a private IP address and the other with the public IP address. For a node using Windows 2000, for example, complete the following procedure to assign IP address information to each network adapter:

    1. Navigate to Start > Settings > Control Panel > Network and Dial-up Connections > Local Area Connection > Properties

    2. Double-click Internet Protocol (TCP/IP)

    3. Click Use the following IP address and enter the required IP address components. Also specify your DNS server IP address.

    4. Click OK on each intermediate open window and Close on the main Local Area Connection Status window to complete the task.

  4. If you need to change a network interface name, follow these steps:

    1. Navigate to Start > Settings > Control Panel > Network and Dial-up Connections

    2. Right click the icon of the network interface for which you need to change the name

    3. Select Rename

    4. Enter and save the new name

  5. On both nodes, edit the %SystemRoot%\system32\drivers\etc\hosts file to add an entry for each of the private IP addresses. Because the private IP addresses are not accessible on the public network, you do not need to register them with your DNS. The following example uses the values from the preceding table, you should substitute your own values if they are different:     rac1-priv rac2-priv

  6. From a Command window on one node, execute a ping command, using the IP address or alias name for the other node's private IP address, and another ping command for its public IP address. Repeat this process from a Command window on the other node.

    If any of the ping commands fail to receive a reply, there is a configuration problem that must be resolved before you proceed.

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