Oracle Database File Mapping for Oracle ASM Files

For an understanding of I/O performance, you must have detailed knowledge of the storage hierarchy in which files reside. Oracle Database provides a set of dynamic performance views to show a complete mapping of a file to intermediate layers of logical volumes to actual physical devices. Using these dynamic views, you can locate the exact disk on which any block of a file resides.

Oracle Database communicates with a background process called FMON to manage the mapping information. Oracle provides the PL/SQL DBMS_STORAGE_MAP package to invoke mapping operations that populate the mapping views.

Oracle Database file mapping does not require third party libraries when mapping Oracle ASM files. In addition, Oracle Database supports Oracle ASM file mapping on all operating system platforms.

All the example in this section are run on the Oracle Database instance.

For information about file mapping with Oracle ACFS files, refer to "Oracle ACFS Support for Oracle Database File Mapping Views".

This section contains the following topics:

• Enabling File Mapping With Oracle ASM Files

• Using File Mapping Views With Oracle ASM Files

• Using the DBMS_STORAGE_MAP Package With Oracle ASM Files