ODM enables the following performance benefits that are provided by the Oracle Disk Manager:

• Locking for data integrity.

• Few system calls and context switches.

• Increased I/O parallelism.

• Efficient file creation and disk allocation.

Databases using file systems typically incur the following additional overhead:

• Extra CPU and memory usage to read data from underlying disks to the file system cache. This scenario requires copying data from the file system cache to the Oracle cache.

• File locking that allows for only a single writer at a time. Allowing Oracle to perform locking allows for finer granularity of locking at the row level.

• File systems generally go through a standard Sync I/O library when performing I/O. Oracle can make use of Kernel Async I/O libraries (KAIO) with raw devices to improve performance.