LOG_ARCHIVE_DEST_n

{ null_string |
 { LOCATION=path_name | SERVICE=service_name }
 [ { MANDATORY | OPTIONAL } ]
 [ REOPEN[=seconds] ]
 [ DELAY[=minutes] ]
 [ NOREGISTER ]
 [ TEMPLATE=template] ]
 [ ALTERNATE=destination ]
 [ DEPENDENCY=destination ]
 [ MAX_FAILURE=count ]
 [ ARCH | LGWR ]
 [ SYNC | ASYNC ]
 [ AFFIRM | NOAFFIRM ]
 [ NET_TIMEOUT=seconds ]
 [ VALID_FOR=(redo_log_type,database_role) ]
 [ DB_UNIQUE_NAME ]
 [ VERIFY ]
 }

The LOG_ARCHIVE_DEST_n initialization parameter defines up to ten (where n = 1, 2, 3, ... 10) destinations, each of which must specify either the LOCATION or the SERVICE attribute to specify where to archive the redo data. All other attributes are optional. Note that whether you are specifying the LOCATION attribute or the SERVICE attribute, it must be the first attribute supplied in the list of attributes.

If you choose not to enter any attributes, you can specify a null string by entering the following:

LOG_ARCHIVE_DEST_n=' ';

You set the attributes for the LOG_ARCHIVE_DEST_n initialization parameter to control different aspects of how redo transport services transfer redo data from a production or primary database destination to another (standby) database destination. You can query the V$ARCHIVE_DEST view to see the current attribute settings for each destination (n).

For every LOG_ARCHIVE_DEST_n initialization parameter that you define, you must specify a corresponding LOG_ARCHIVE_DEST_STATE_n parameter. The LOG_ARCHIVE_DEST_STATE_n (where n is an integer from 1 to 10) initialization parameter specifies whether the corresponding destination is currently enabled or disabled.

Values:

• AFFIRM and NOAFFIRM

  Control whether or not redo transport services use synchronous or asynchronous disk I/O to write redo data to the archived redo log files. The default is NOAFFIRM.

• ALTERNATE=LOG_ARCHIVE_DEST_n

  Specifies an alternate archiving destination to be used when the original destination fails. There is no default value; if an alternate destination is not specified, then archiving does not automatically change to another destination if the original destination fails.

• ARCH

  Uses the archiver processes (ARCn) to collect transaction redo data and transmit it to standby destinations. If neither the ARCH or LGWR attribute is specified, the default is ARCH.

• ASYNC

  Specifies that network I/O is to be done asynchronously when archival is performed using the log writer process (LGWR) and the network server (LNSn) processes.

• DB_UNIQUE_NAME=name

  Specifies a unique name for the database at this destination. You must specify a name; there is no default value.

• DELAY[=minutes]

  Specifies a time lag between when redo data is archived on a physical standby site and when the archived redo log file is applied to the physical standby database. You cannot set the DELAY attribute for a logical standby database destination. If you specify the DELAY attribute without a time interval, the default is 30 minutes.

• DEPENDENCY=LOG_ARCHIVE_DEST_n

  Defines one archival destination to receive redo data on behalf of several destinations. Redo transport services transmit redo data to the destination that then shares its archived redo log files with multiple standby databases.

• LGWR

  Uses the log writer process (LGWR) to collect transaction redo data and transmit it to standby destinations. If neither the ARCH or LGWR attributes are specified, the default is ARCH.

• LOCATION=local_disk_directory or USE_DB_RECOVERY_FILE_DEST

  Specifies either a local file system destination or the directory, file system, or Oracle Storage Manager disk group that will serve as the flash recovery area. You must specify this attribute for at least one destination. You can specify either a local disk directory or flash recovery area with the LOCATION attribute. You must include either the LOCATION or the SERVICE attribute for each destination to specify where to archive the redo data.

• MANDATORY

  Specifies that the transmission of redo data to the destination must succeed before the local online redo log file can be made available for reuse. If neither the MANDATORY nor the OPTIONAL attribute is specified, the default is OPTIONAL.

• MAX_CONNECTIONS

  Specifies the maximum number of network connections that can be used to transmit redo data to this destination.

• MAX_FAILURE

  Controls the consecutive number of times redo transport services attempt to reestablish communication and transmit redo data to a failed destination before the primary database permanently gives up on the standby database.

• NET_TIMEOUT=seconds

  Specifies the number of seconds the log writer process on the primary system waits for status from the network server (LNSn) process before terminating the network connection. The default is 180 seconds.

• NOREGISTER

  Indicates that the location of the archived redo log file is not to be recorded at the corresponding destination.

• OPTIONAL

  Specifies that successful transmission of redo data to the destination is not required before the online redo log file can be made available for reuse. If neither the MANDATORY nor the OPTIONAL attribute is specified, the default is OPTIONAL.

• REOPEN[=seconds]

  Specifies the minimum number of seconds before the archiver processes (ARCn) or the log writer process (LGWR) should try again to access a previously failed destination. The default is 300 seconds.

• SERVICE=net_service_name

  Specifies a valid Oracle Net service name (SERVICE=net_service_name) that identifies the remote Oracle database instance to which redo data will be sent. Each destination must specify either the LOCATION or the SERVICE attribute. There is no default net service name.

• SYNC

  Specifies that network I/O is to be performed synchronously for the destination, which means that once I/O is initiated, the log writer process waits for the I/O to complete before continuing. The SYNC attribute is one requirement for setting up a no-data-loss environment, because it ensures the redo records are successfully transmitted to the standby destination before continuing

• TEMPLATE=filename_template_%t_%s_%r

  Defines a directory specification and format template for names of the archived redo log files or standby redo log files at the standby destination. The definition is used to generate a filename that is different from the default filename format defined by the STANDBY_ARCHIVE_DEST and LOG_ARCHIVE_FORMAT initialization parameters at the standby destination. There is no default template format.

• VALID_FOR=(redo_log_type, database_role)

  Identifies when redo transport services can transmit redo data to destinations based on the following factors:

  • redo_log_type—whether online redo log files, standby redo log files, or both are currently being archived on the database at this destination

  • database_role—whether the database is currently running in the primary or the standby role

• VERIFY

  Indicates if an archiver (ARCn) process should scan and verify the correctness of the contents of a completed archived redo log file, either local or remote, after successfully completing the archival operation. By default, archived redo log files are not verified.

Deprecated Attributes for LOG_ARCHIVE_DEST_n

The following attributes are deprecated for the LOG_ARCHIVE_DEST_n parameter. They are retained for backward compatibility only.

In addition, note the following changes to the ASYNC and SYNC attributes:

• The BLOCKS keyword on the ASYNC attribute is no longer needed.

  It is no longer necessary to set this keyword because Data Guard dynamically adjusts the block count up or down to an appropriate number of blocks, as necessary.

• The PARALLEL and NOPARALLEL keywords on the SYNC attribute are no longer needed.