dbcc commands are either:
Database-specific – dbcc commands that execute on a particular target database (for example, checkalloc, checktable, checkindex, checkstorage, checkdb, checkcatalog, checkverify, fix_text, indexalloc, reindex, tablealloc, and textalloc). Although these commands are database-specific, only system administrators can grant or revoke them.
Server-wide – dbcc commands such as tune that are effective server-wide and are not associated with any particular database. These commands are granted server-wide by default and are not associated with any database.
System administrators can allow users to execute the dbcc command in all databases by making them valid users in those databases. However, it may be more convenient to grant dbcc to roles instead of individual users, since this allows users to use databases as a “guest” user instead of requiring that they each be added manually to the database.
From a security administration perspective, system administrators may prefer to grant permission to execute database-specific dbcc commands server-wide. For example, you can execute grant dbcc checkstorage on all databases to a user-defined role called storage_admin_role, thereby eliminating the need to execute grant dbcc checkstorage to storage_admin_role in every database.
The following commands are effective server-wide, but are not database-specific:
Server-wide dbcc commands such as tune.
Database-specific dbcc commands that are granted server-wide, such as grant dbcc checkstorage granted to storage_admin_role.