Automatic Storage Management

Automatic Storage Management (ASM) is a file system and volume manager built into the database kernel that allows the management of disk drives in place of raw or cooked file systems. It provides management across multiple nodes of a cluster for Oracle Real Application Clusters (RAC) support as well as single SMP machines. ASM does automatic load balancing and striping in parallel across all available disk drives to prevent hot spots and maximize performance. In addition, it does automatic online disk space reorganization for the incremental addition or removal of storage capacity.

It can maintain redundant copies of data to provide fault tolerance, or it can be built on top of vendor-supplied reliable storage mechanisms. Data management is done by selecting the desired reliability and performance characteristics for classes of data rather than with configuring the database on a per-file basis.