Alternately Pathing the Primary Network Interface

The primary network interface between your Sun Enterprise server and the other machines on the network is the Ethernet interface that is on the same subnet as the SSP. One way to identify the primary network is to look in the /etc/hostname.xxx files until you find the one that contains the IP name that matches the IP name found in the file /etc/nodename. The corresponding xxx network (for example, qe0) is the primary network.

You can alternately path the primary network, if you want. The primary network is the only network interface that can be auto-switched at boot-time. During the boot process, if the active alternate for the primary network fails, the system attempts to find a working alternate. Note that the AP database on your Sun Enterprise server is used for this purpose.

A subset of the host's AP database that resides on the SSP is used at boot time to automatically switch to a functional path to the boot disk. By the time the system is ready to start using the network, the file systems on the host are already up and running, so the main AP database can be used.

When you configure an alternately pathed network, you must not configure the metanetwork while the underlying driver is still active. When you configure AP for a network that you are currently using, the transition period between configuring the physical interface down and the AP interface up generates a loss of network service for your Sun Enterprise server.

The following example shows how to reconfigure the primary network. This example assumes you have an Sun Enterprise server named hmb with a primary network interface on qe0 and that you want to have a metanetwork interface composed of qe0 and qe4.

To Alternately Path the Primary Network Interface

This procedure requires you to reboot the machine. If you are not ready to reboot the machine, do not perform this procedure.

1. Verify that the primary network interface is qe0:

   # cat /etc/nodename hmb # cat /etc/hostname.qe0 hmb #

2. Create the new network pathgroup and commit the changes:

   # apnet -c -p qe0 -a qe4 # apdb -C

3. Verify the new pathgroup by looking at committed network entries in the AP database:

   # apconfig -N metanetwork: mqe0 physical devices: qe4 qe0 P A

4. Create the new hostname.mxxx file so the network will be automatically configured at boot time:

   # cat > /etc/hostname.mqe0 hmb ^D # cat /etc/hostname.mqe0 hmb

5. Remove the configuration files for the physical network interfaces:

   # rm -f /etc/hostname.qe0 /etc/hostname.qe4

6. Bring down the physical network interfaces and bring up the metanetwork interface by rebooting the machine.