The VALID_FOR attribute is optional. However, Oracle recommends that the VALID_FOR attribute be specified for each redo transport destination at each database in a Data Guard configuration so that redo transport continues after a role transition to any standby database in the configuration.

To configure these factors for each LOG_ARCHIVE_DEST_n destination, you specify this attribute with a pair of keywords: VALID_FOR=(redo_log_type,database_role):

• The redo_log_type keyword identifies the destination as valid for archiving one of the following:

  • ONLINE_LOGFILE—This destination is valid only when archiving online redo log files.

  • STANDBY_LOGFILE—This destination is valid only when archiving standby redo log files.

  • ALL_LOGFILES— This destination is valid when archiving either online redo log files or standby redo log files.

• The database_role keyword identifies the role in which this destination is valid for archiving:

  • PRIMARY_ROLE—This destination is valid only when the database is running in the primary role.

  • STANDBY_ROLE—This destination is valid only when the database is running in the standby role.

  • ALL_ROLES—This destination is valid when the database is running in either the primary or the standby role.

If you do not specify the VALID_FOR attribute for a destination, by default, archiving online redo log files and standby redo log files is enabled at the destination, regardless of whether the database is running in the primary or the standby role. This default behavior is equivalent to setting the (ALL_LOGFILES,ALL_ROLES) keyword pair on the VALID_FOR attribute.

The VALID_FOR attribute enables you to use the same initialization parameter file for both the primary and standby roles.