About Oracle ASM File Names

Every file created in Oracle ASM is provided a file name generated by Oracle Managed Files, known as a fully qualified file name (or system-generated file name). The fully qualified file name represents a complete path name in the Oracle ASM file system. An example of a fully qualified file name is:

+data/orcl/controlfile/Current.256.541956473

You can use the fully qualified file name to reference (read or retrieve) an Oracle ASM file. You can also use other abbreviated file name formats, such as an alias Oracle ASM file name described in "Alias Oracle ASM File Name Forms", to reference an Oracle ASM file.

Oracle ASM generates a fully qualified file name upon any request to create a file. A creation request does not or cannot specify a fully qualified file name. Instead, it uses a simpler syntax to specify a file, such as an alias or just a disk group name. Oracle ASM then creates the file, placing it in the correct Oracle ASM path according to file type, and then assigns an appropriate fully qualified file name. If you specify an alias in the creation request, Oracle ASM also creates the alias so that it references the fully qualified file name.

Oracle ASM file creation requests are either single file creation requests or multiple file creation request.

Note:

  • You can find the generated name in database views displaying Oracle file names, such as V$DATAFILE and V$LOGFILE. You can use this name, or an abbreviated form of it, if you later must reference an Oracle ASM file in a SQL statement. As with other Oracle Database file names, Oracle ASM file names are kept in the control file and the RMAN catalog.

  • You can use fully qualified and numeric file names in single-file creation if you specify the REUSE keyword, as described in "Using Oracle ASM File Names in SQL Statements".

  • Forward slash (/) and backslash (\) are interchangeable in file names. File names are case insensitive, but case retentive.

This section contains the following topics:

Table 5-2 specifies the valid usage for each file name form. If the form is used for file creation, the table specifies whether the created file is an Oracle Managed Files (OMF).

Table 5-2 Valid usage for Oracle ASM file name forms

File Name Form Reference to File? Single-file Creation? Multiple File Creation? Created as OMF?

Fully qualified file name

Yes

No

No

No

Alias file name

Yes

Yes

No

No

Alias with template file name

No

Yes

No

No

Incomplete file name

No

Yes

Yes

Yes

Incomplete file name with template

No

Yes

Yes

Yes