by default the filer will not take over on a multiple-link failure. To enable it, set the option "cf.takeover.on_network_interface_failure" to on.
Note that this only applies to interfaces that have the "-nfo" (negotiated failover) flag set. i.e. you have to change your /etc/rc to include this flag in the ifconfig command line
the other filer will take over when ALL these marked interfaces are down. to change it to take over whenever ANY of the flagged interfaces are down, set the option "cf.takeover.on_network_interface_failure.policy" to "any_nic"
see the manual page for the "options" command for more info, as well as the active/active admin guide.
-Michael