Instructions for Changing Interfaces on Linux/Unix systems

You can change the interface information for a cluster using the following as an example:

1. First - Use the getif option to show the currently configured interfaces. This will display the interfaces that are currently stored in the OCR, what their subnets are, and what their role is (i.e. public or cluster_interconnect). This example is from a Linux system, but the syntax is the same for any platform. On Unix/Linux systems, the interface names are generally assigned by the OS, and standard names vary by platform. (For Windows systems, see additional notes below) :

2.   If the public interface IP needs to be changed, there is not a 'modify' option - you will need to delete the interface and add it back with the correct subnet IP. So, in the example here, the subnet is being changed from 10.2.156.0 to 10.2.166.0 via two separate commands - first a 'delif' followed by a 'setif':

syntax: oifcfg setif /:

3. The same step could be use for the private interface:

4. Verify the correct interface subnet is in use by re-running oifcfg with the 'getif' option:

Notes for Windows Systems

The syntax for changing the interfaces on Windows/RAC clusters is the same as on Unix or Linux, but the interface names will be slightly different.   On Windows systems, the default names assigned to the interfaces are generally names such as:

Local Area Connection
Local Area Connection 1
Local Area Connection 2

If you are using an interface name that has spaces in it, such as the examples above, you must enclose the name in quotes.   Also, be aware that it is case sensitive. So for example, on Windows, you would use syntax such as the following to add the public subnet in:

However, it is common practice on Windows to rename the interfaces to use names that are more meaningful, such as renaming them to 'Public' and 'Private'.   If interface names are renamed after CRS is installed, then you will need to run 'oifcfg' to delete the old interface and add the new one back in, as described above.

You can view the available interface names on each node by running the command:

This command must be run on each node, as the 'iflist' option is showing the interface names that exist at the operating system level on that particular node.   On the other hand, commands such as 'oifcfg getif', 'oifcfg delif' and 'oifcfg setif' are actually reading/updating the OCR, which is a shared resource. So these commands need only be run one time, and should be runnable from any node in the cluster.

Ramifications of Changing Interface Names Using oifcfg

The ramifications of changing the interface names depends on which name you are changing, and whether or not you are also changing the IP address. In cases where only the interface names are being changed, the ramifications are minor. If you change the name for the Public Interface that is stored in the OCR, you will also need to modify the nodeapps for each node.   Therefore, the nodeapps will have to be brought down in order for this change to take effect.   See Note 276434.1 for more details on changing the nodeapps to use a new public interface name.

For the Private interface, the database will use the interface stored in the OCR and defined as a 'cluster_interconnect' for cache fusion traffic. You will be able to see this at startup in the alert log, after the parameter listing - for example:

If this is incorrect, then once you have corrected the entries stored in the OCR (by using 'oifcfg' as described in this note) you will have to restart the instance in order for it to re-read the OCR and pick up the correct network. This applies to ASM instances and Database instances alike.