Oracle Archive Log

What is oracle archive log?
Oracle stores the history of transaction that occur in the database in the archive log. It uses to recover a database, update a standby database and getting the history information of the database using a log miner utility.

All the archive log destination information can be found from this table: V$ARCHIVE_DEST


Understanding the archive destination
We can choose on how many location we want to store the archived redo log information. It can be a single location or multiple destination. For DR system, we can specify the second location as a method of delivery/shipment of the archived redo log.

For a single location, you can use the parameter LOG_ARCHIVE_DEST.

For multiple location, there are 2 method in doing this:

• First method
  parameter: LOG_ARCHIVE_DEST_n
  -Where n can be any destination that you wanted. This can be local or remote host
• Second method
  parameter: LOG_ARCHIVE_DEST , LOG_ARCHIVE_DUPLEX_DEST
  - This can be only on local host

LOG_ARCHIVE_DEST_n value
Two values that can set for the parameter:

1. LOCATION
   - for local filesystem
   - e.g. : LOG_ARCHIVE_DEST_1 = 'LOCATION=/disk1/arc'
2. SERVICE
   - Remote archival through Oracle Net service name. This is based on tnsnames.ora file set in ORACLE_HOME/920/Network/admin folder.
   - e.g. : 'SERVICE=standby1'