n

Parameter type	String
Syntax	DB_CREATE_ONLINE_LOG_DEST_[1 | 2 | 3 | 4 | 5] = directory
Default value	There is no default value.
Parameter class	Dynamic: ALTER SESSION, ALTER SYSTEM

DB_CREATE_ONLINE_LOG_DEST_n (where n = 1, 2, 3, ... 5) sets the default location for Oracle-managed control files and online redo logs.

You should specify at least two parameters: DB_CREATE_ONLINE_LOG_DEST_1 and DB_CREATE_ONLINE_LOG_DEST_2. This provides greater fault tolerance for the logs if one of the destinations should fail.

If more than one directory is specified, then the control file or online redo log is multiplexed across the directories. One member of each online redo log is created in each directory, and one control file is created in each directory.

The directory must already exist; Oracle does not create it. The directory must have appropriate permissions that allow Oracle to create files in it. Oracle generates unique names for the files, and a file thus created is an Oracle-managed file.