Oracle ASM automatically maximizes I/O performance by managing the storage configuration across the disks that Oracle ASM manages. Oracle ASM does this by evenly distributing the database files across all of the available storage assigned to the disk groups within Oracle ASM. Oracle ASM allocates your total disk space requirements into uniformly sized units across all disks in a disk group. Oracle ASM can also automatically mirror files to prevent data loss. Because of these features, Oracle ASM also significantly reduces your administrative overhead.
Oracle ASM instances are created on each node where you install Oracle Clusterware. Each Oracle ASM instance has either an SPFILE or PFILE type parameter file. Oracle recommends that you back up the parameter files and the TNS entries for nondefault Oracle Net listeners.
To use Oracle ASM with Oracle RAC, select Oracle ASM as your storage option when you create your database with the Database Configuration Assistant (DBCA). As in noncluster Oracle databases, using Oracle ASM with Oracle RAC does not require I/O tuning.
The following topics describe Oracle ASM and Oracle ASM administration, as follows:
Oracle Automatic Storage Management Administrator's Guide for complete information about managing Oracle ASM