The example illustrates file groups in a multitenant environment. Each PDB has a file group, the file group belongs to a quota group, and resides in a disk group. Note that the file group name and the quota group name is unique in a disk group. The same name may be used in different disk groups. You can use this for easy identification. A PDB may have only one file group in a disk group. A quota group may contain multiple file groups. The file groups and quota group may be administered with commands in SQL*Plus or ASMCMD.
- A disk group contains at least one file group, the default file group.
- A disk group can contain multiple file groups.
- A disk group must have FLEX or EXTENDED redundancy to contain a file group.
- A disk group can store files belonging to multiple databases with each database having a separate file group.
- A database can have only one file group in a disk group.
- A database can span multiple disk groups with multiple file groups in different disk groups. The file groups belonging to a database in multiple disk groups should all have the same name for consistency and easy identification.
- A file group can belong to only one disk group.
- A file group can describe only one database, PDB, CDB, volume, or cluster.
- A file group can belong to only one quota group.
- Automatically created file groups are associated with the generic quota group.
- When a database, PDB, or CDB is created, if an existing file group has a client ID or name that matches the ID or name of the database, PDB, or CDB, then that file group is used to describe its files. Otherwise, a new file group is created for the database, PDB, or CDB.