About Read-Only Oracle Homes

In Oracle Database 21c, an Oracle Database installation configures all Oracle Database homes in read-only mode by default. A read-only Oracle home does not imply that the file system and the Oracle home is in read-only mode. The file system and mount point should always be in read/write mode.

A read-only Oracle Home simplifies provisioning by implementing separation of installation and configuration.

Before Oracle Database 21c, the default ORACLE_HOME layout combined ORACLE_HOME, ORACLE_BASE_HOME and ORACLE_BASE_CONFIG into a single location. Starting with Oracle Database 21c, the only available configuration is a read-only ORACLE_HOME where ORACLE_BASE_HOME and ORACLE_BASE_CONFIG are located separately from ORACLE_HOME.

In a read-only Oracle home, all the configuration data and log files reside outside of the read-only Oracle home. See File Path and Directory Changes in Read-Only Oracle Homes.

Apart from the traditional ORACLE_BASE and ORACLE_HOME directories, the following directories contain files that used to be in ORACLE_HOME:

• ORACLE_BASE_HOME

• ORACLE_BASE_CONFIG

Ensure that you enable read-only Oracle home before you create the database or listener.

When you run the roohctl script to enable a read-only Oracle home, the Oracle home file system will continue to be a read/write file system.

Note:

This feature does not affect how database administrators monitor, diagnose, and tune their system performance.