It is technically possible to store your database files on ACFS, no question about that. I already deployed a number of test databases on ACFS. However, the Oracle 11g Release 2 Storage Administrator's Guide, Chapter 5 states:
Oracle ASM is the preferred storage manager for all database files. It has been specifically designed and optimized to provide the best performance for database file types.
Oracle ACFS is the preferred file manager for non-database files. It is optimized for general purpose files.
Oracle ACFS does not support any file that can be directly stored in Oracle ASM.
Not supported means Oracle Support Services will not take calls and development will not fix bugs associated with storing unsupported file types in Oracle ACFS.
Here is the list of file types that are NOT supported to be stored on ACFS:
|Redo log files|
|Archive log files|
|Data file backup pieces|
|Data file incremental backup pieces|
|Archive log backup piece|
|Data file copy|
|Persistent initialization parameter file (SPFILE)|
|Change tracking file|
|Data Pump dumpset|
|Automatically generated control file backup|
|Cross-platform transportable data files|
|Oracle ASM Persistent initialization parameter file (SPFILE)|
|Oracle Cluster Registry file|
Be aware of this when you are designing your Grid Infrastructure!