You can choose any combination of the supported shared storage options for each file type if you satisfy all requirements listed for the chosen storage option.

• Guidelines for Using Oracle ASM Disk Groups for Storage
  Plan how you want to configure Oracle ASM disk groups for deployment.
• Guidelines for Using Direct Network File System (NFS) with Oracle RAC
  Network-attached storage (NAS) systems use a network file system (NFS) to access data. You can store Oracle RAC data files and recovery files on a supported NAS server using Direct NFS Client.