moving Oracle Apps 11.0.3 Instance to SAN

Dear Friends

Currently we are having three servers one GS80 and two GS60's (Diagram Attached). The GS80 server is running SAC Oracle ERP and is connected to a SAN storage where the application and database are stored. One of the GS 60's is ruing SAS ERP on a local storage and the other GS60 is running In-house Oracle databases also in a local storage.

We are planning to expand the SAN storage being used now by the GS80 server and connect all the three serves to it in which every server will be running the same application that it is running now. However, if one of the servers fails, then other servers should take the load of the failing server until it is fixed. Pls. note that we are not planning to use Oracle RAC in this setup

please guide me how we can acheive this ,please guide me step by step or what methodology we should use?

Thanks in Advance
Sonu Saxena