About ORATAB Configuration for Oracle RAC
Oracle creates an entry for each Oracle RAC database in the oratab configuration file.
The oratab file is created by the root.sh script during installation, and it is updated by the Database Configuration Assistant when creating or deleting a database.
oratab entries if the node is pinned in the CSS. The oratab file entry is also created automatically by the Database Agent when a database is first started on a node where it has not run previously, if your system meets any of the following conditions:
- The database release is Oracle Database 12c Release 1 (12.1) or earlier
- The database is a single instance Oracle Database
- The database is an admin-managed Oracle RAC database
Oracle Enterprise Manager uses the oratab file during service discovery to determine the name of the Oracle RAC database, and to determine if the database must be started automatically when the system is restarted.
The database entry has the following syntax:
$DB_UNIQUE_NAME:$ORACLE_HOME:N
A colon (:) is used as the field terminator. A new line terminates the entry. Lines beginning with a pound sign (#) are comments. Because all the instances of an Oracle RAC database have the same DB_UNIQUE_NAME, but each instance has its own ORACLE_SID, use the $DB_UNIQUE_NAME environment variable in the oratab file as the database entry.
The $DB_UNIQUE_NAME identifier for your Oracle RAC database must be unique across your enterprise. $ORACLE_HOME is the directory path to the database, and N indicates that the database should not be started at restart time. The following is an example entry for a database named sales:
sales:/u01/app/oracle/sales:N
Parent topic: Understanding the Oracle RAC Installed Configuration