Configuring mirrored, dual-MAC interfaces

Prerequisites for configuring dual-MAC interfaces

To configure a pair of failover, dual-MAC interfaces, one on each filer in the cluster, so that one can replace the other if one filer fails and is taken over, you must have available the following items:

Two dual-MAC interfaces, one installed on each filer in the cluster
Two IP addresses, the address of one interface on each filer in the cluster

Emulated LAN considerations

For LANE, when an adapter is shared, an Emulated LAN cannot be configured more than once on the adapter after takeover. This means that if both filers in a cluster pair are on the same Emulated LAN, each filer needs a minimum of two ATM cards to support full takeover.

Configuring dual-MAC interfaces

To configure a pair of dual-MAC interfaces for takeover, complete the following step.

Step	Action
1	Enter the following command on the command line of both filers in a cluster and in the /etc/rc file of both filers so that the command is permanent: ifconfig interface address partner address interface is the name of the local interface. The first address is the IP address of the local interface. The second address is the IP address or interface name that the local interface services when the local filer has taken over the other filer in the cluster. Note When you configure virtual interfaces for takeover, you must specify the interface name and not the IP address.

Step

Action

Enter the following command on the command line of both filers in a cluster and in the /etc/rc file of both filers so that the command is permanent:

ifconfig interface address partner address

interface is the name of the local interface.

The first address is the IP address of the local interface.

The second address is the IP address or interface name that the local interface services when the local filer has taken over the other filer in the cluster.

Note
When you configure virtual interfaces for takeover, you must specify the interface name and not the IP address.

Takeover configuration with shared interfaces

In the following configuration illustration, you use two network cards that support two MAC addresses to mirror two interfaces, as shown with the interfaces that connect to the 230 net.

With the configuration shown in the preceding figure, if Filer 1 fails, the following occurs on takeover:

Interface e0 on Filer 1 stops functioning, but the secondary address on e0 on Filer 2 handles the Filer 1 network connection with the 230 network.
Interface e1 on Filer 1 stops functioning, but e1 on Filer 2 substitutes for the failed interface and handles the Filer 1 network connection with the 223 network.

If Filer 2 fails, e0 on Filer 2 stops functioning; e0 on Filer 1 substitutes for the failed interface, however, and handles the Filer 2 network connection with the 230 network.

Emulated LAN example

The following command specifies that adapter a4 will take over all the Emulated LANs on the partner a5 interface.

ifconfig a4 partner a5

Note
If a4 and partner a5 are configured with common Emulated LANs, a4 does not take over those Emulated LANs.

A cluster pair might be configured with Emulated LANs as follows.

Filer and adapter	Interfaces and Emulated LANS	Filer and adapter	Interfaces and Emulated LANS
filer1-a4	el0 default el1 nineKMTU	filer1-a5	el2 eighteenKMTU
filer2-a4	el0 default el1 nineKMTU	filer2-a5	el2 eighteenKMTU

To achieve full takeover, you would use the first command on one filer and the second command on the second filer:

ifconfig a4 partner a5

ifconfig a5 partner a4

Virtual interface example

The following is an example of a virtual interface configuration command:

ifconfig vif0 partner vif0