How are archive destinations specified?

How are archive destinations specified?

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When archiving redo logs, it must be decided whether to archive them to a single archive destination or multiplex them. When the archived redo logs are multiplexed, they are archived to more than one archive destination. The following two methods can be used to specify archive destinations:

1. Using the LOG_ARCHIVE_DEST_n initialization parameter: The LOG_ARCHIVE_DEST_n (where n is an integer from 1 to 10) initialization parameter can be used to specify a maximum of ten different local or remote archive destinations. Each numerically suffixed parameter (e.g., LOG_ARCHIVE_DEST_1, LOG_ARCHIVE_DEST_2, etc.) uniquely identifies an individual destination.
   
   For specifying a local archive destination, the LOCATION keyword is used with the LOG_ARCHIVE_DEST_n initialization parameter.
   
   Example:
   
   LOG_ARCHIVE_DEST_1 = 'LOCATION = /Disk1/Archive'
   LOG_ARCHIVE_DEST_2 = 'LOCATION = /Disk2/Archive'
   
   The LOCATION keyword specifies an operating system-specific path name.
   
   For specifying a remote archive destination (e.g., a remote standby database), the SERVICE keyword is used with the LOG_ARCHIVE_DEST_n initialization parameter.
   
   Example:
   
   LOG_ARCHIVE_DEST_4 = 'SERVICE = Standby_Dbase1'
   
   The SERVICE keyword specifies a valid net service name or alias. Oracle resolves the net service name to a connect descriptor by using a tnsnames.ora file. The connect descriptor contains the information necessary for connecting to the remote standby database. The net service name must have an associated database system identifier (SID), so that Oracle correctly updates the log history of the control file for the remote standby database.
   
   The destinations specified by the LOG_ARCHIVE_DEST_n initialization parameter can be established as mandatory or optional by using the MANDATORY or OPTIONAL keyword respectively with the LOG_ARCHIVE_DEST_n initialization parameter. If no keyword is specified, it is taken as OPTIONAL. The archiver process (ARCn) must successfully archive a redo log to a mandatory archive destination before the redo log can be reused.



2. Using the LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST initialization parameters: This method allows specifying a maximum of two archive destinations. The LOG_ARCHIVE_DEST initialization parameter is used to specify a primary local archive destination, and the LOG_ARCHIVE_DUPLEX_DEST initialization parameter is used to specify an optional secondary local archive destination. These parameters cannot be used to specify a remote archive destination. Whenever Oracle archives a redo log, it archives it to both destinations.
   
   Example:
   
   LOG_ARCHIVE_DEST = '/Disk1/Archive'
   LOG_ARCHIVE_DUPLEX_DEST = '/Disk2/Archive'


Any archive destination declared by the LOG_ARCHIVE_DEST initialization parameter is mandatory. However, any archive destination declared by the LOG_ARCHIVE_DUPLEX_DEST initialization parameter is optional if LOG_ARCHIVE_MIN_SUCCEED_DEST = 1, and mandatory if LOG_ARCHIVE_MIN_SUCCEED_DEST = 2. Where, LOG_ARCHIVE_MIN_SUCCEED_DEST is an optional initialization parameter that determines the minimum number of archive destinations to which the archiver process (ARCn) must successfully archive a redo log before the redo log can be reused.

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