How ASM Names Files

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.

A fully qualified file name has the following form in a non-multitenant environment:
+diskgroup/dbname/filetype/filetypetag.file.incarnation

With multitenant databases, a fully qualified file name has the following form
+diskgroup/cdb/pdb_guid/filetype/filetypetag.file.incarnation

filetype is the Oracle file type eg. CONTROLFILE, DATAFILE,ONLINELOG,ARCHIVELOG etc.

file.incarnation is the file/incarnation pair, used to ensure uniqueness.

cdb is the name of the CDB

pdb_guid is the PDB GUID value

Examples of fully qualified Oracle ASM file names are:

SQL> SELECT NAME FROM V$DATAFILE;
NAME
---------------------------------------------------------------------
+DG_TST_DATA/TST1T/DATAFILE/system.261.987251371
+DG_TST_DATA/TST1T/7637E1C08DFB31DFE0530601A8C097C7/DATAFILE/system.262.987251377
+DG_TST_DATA/TST1T/DATAFILE/sysaux.263.987251383
+DG_TST_DATA/TST1T/7637E1C08DFB31DFE0530601A8C097C7/DATAFILE/sysaux.264.987251385
+DG_TST_DATA/TST1T/DATAFILE/undotbs1.265.987251387
+DG_TST_DATA/TST1T/7637E1C08DFB31DFE0530601A8C097C7/DATAFILE/undotbs1.266.987251391
+DG_TST_DATA/TST1T/DATAFILE/users.269.987251429
+DG_TST2_DATA/TST1T/DATAFILE/afac_tst.269.987348441
+DG_FLEX_DATA/TST1T/769E1B25EFDA4E86E0530601A8C0A64C/DATAFILE/system.256.987690421

+DG_FLEX_DATA/TST1T/769E1B25EFDA4E86E0530601A8C0A64C/DATAFILE/sysaux.258.987690421
+DG_FLEX_DATA/TST1T/769E1B25EFDA4E86E0530601A8C0A64C/DATAFILE/undotbs1.257.987690421