Seeing as the specific data in question could be considered readonly to the majority of clients, why not have them use an automount map with both filers in.
We do that for our centrally maintained and served binaries and db's and it works very well.
Hi,
We have two netapp filers serving mainly static data (updated overnight) to several hp-ux clients.
If one server fails we can swap the clients onto the other server by mounting and switching symbollic links.