Files in Support of Backup and Recovery Operations - Oracle RMAN for Absolute Beginners - page 34

Here is a partial listing of the output:

NAME TYPE VALUE
---------------------- ----------- --------------------------
log_archive_dest string
log_archive_dest_1 string location=/u01/oraarch/O12C
log_archive_dest_10 string

For Oracle 11g and higher you can enable up to 31 different locations for the archive redo log file destination. For
most production systems one archive redo log destination location is usually sufficient. If you need a higher degree
of protection, you can enable multiple destinations. Keep in mind that when you use multiple destinations, the
archiver must be able to write to at least one location successfully. If you enable multiple mandatory locations and
set LOG_ARCHIVE_MIN_SUCCEED_DEST to be higher than 1, then your database may hang if the archiver can't write to all
mandatory locations.
You can check the details regarding the status of archive redo log locations via this query:

SQL> select dest_name, destination, status, binding from v$archive_dest;

DEST_NAME DESTINATION STATUS BINDING
-------------------- -------------------- --------- ---------
LOG_ARCHIVE_DEST_1 /u01/archive/O12C VALID OPTIONAL
LOG_ARCHIVE_DEST_2 INACTIVE OPTIONAL
...

Using the FRA for Archive Log Files
The FRA is an area on disk—specified via database initialization parameters—that can be used to store files, such as
archive redo logs, RMAN backup files, flashback logs, and multiplexed control files and online redo logs. To enable the
use of a FRA, you must set two initialization parameters (in this order):

•

DB_RECOVERY_FILE_DEST_SIZE specifies the maximum space to be used for all files that are
stored in the FRA for a database.

DB_RECOVERY_FILE_DEST specifies the base directory for the FRA.
When you create a FRA, you're not really creating anything—you're telling Oracle which directory to use when
storing files that go in the FRA. For example, say 200GB of space are reserved on a mount point, and you want the base
directory for the FRA to be /u01/fra . To enable the FRA, first set DB_RECOVERY_FILE_DEST_SIZE :

•

SQL> alter system set db_recovery_file_dest_size=200g scope=both;

Next, set the DB_RECOVERY_FILE_DEST parameter:

SQL> alter system set db_recovery_file_dest='/u01/fra' scope=both;

If you're using an init.ora file, modify it with an OS utility (such as vi ) with the appropriate entries.
After you enable a FRA, by default, Oracle writes archive redo logs to subdirectories in the FRA.

■ if you've set the LOG_ARCHIVE_DEST_N parameter to be a location on disk, archive redo logs aren't written
to the Fra.

Note