The LUNS (devices) are only "seen" by only one node in my Cluster

Hi everybody,

We are configuring a new Oracle 11g R2 RAC database (two nodes), and the storage administrator has already configured several LUNs required by ASM.
The external shared storage is comprised of EMC's Symetrix disk (also, we are using EMC Power Path).

My question follows:

The storage administrator told me that the LUNs (devices) only can be seen by the first node. It is to say, the second node cannot "see" the external LUNs in the EMC2 SAN.

I know that we can use a volume manager (example, Veritas Volume Manager) in order to make the LUNs device shared for the cluster as a whole. Another alternative is to