When you have only one network adaptor in the multipathing group, you can configure the network adaptor to detect failures on that NIC alone.
Because failovers cannot occur with only one NIC in the group, you do not need a separate test address on each of the physical interface in the group. You can configure the normal address as an IFF_NOFAILOVER address, which is sufficient for the daemon to send out probes on that interface. Unlike the multiple physical interface case, you do not have to mark it deprecated. Because there is only one interface in the group, addresses can not failover to a different interface. Hence, using this address does not cause any application failures.
Use the following syntax to configure the interface's IPv4 address as a NOFAILOVER:
# ifconfig interface-name -failover group group-name
For IPv6, use the following syntax:
# ifconfig interface-name inet6 -failover group group-name
When the daemon detects failures, the interface is marked and logged appropriately on the console.
You cannot verify whether the target being probed has failed or the NIC has failed, because there is only one physical interface through which the target can be probed. If there is only one default router on the subnet, you should turn off multipathing when there is a single physical interface in the group. If a separate IPv4 and IPv6 default router exists (or multiple default routers exist), there is at least more than one target to probe. Hence, it is safe to turn on multipathing.