ASM – Automatic Storage Management

 

ASM : is the vertical integration of File system and Volume Manager, specifically built for Oracle Database files.

Advantages:

1. Dynamic storage management, without shut downs of the Oracle database, storage can be adjusted.
2. I/O Load balancing : distribute the I/O Load across all available resource to optimize the performance, while removing the manual need.
3. Provide fault tolerance by maintaining redundant copy of data, per file basis.
   Supports mirroring at file level not at volume level.
4. Supports online disk reconfiguration and dynamic rebalancing
5. stripes files not the logical volumes
6. Supports RAC and eliminates need of
   Cluster File system or Cluster Logical Volume Manager.

ASM divides data files into extent. This extent is different from data file extent.
Spread each extents across all the disks. It uses indexes to track the placement of each extent.