17 LOG_ARCHIVE_DEST_n Parameter Attributes

This is a list of the attributes for the LOG_ARCHIVE_DEST_n initialization parameter, (where n is an integer between 1 and 31).

• AFFIRM and NOAFFIRM

• ALTERNATE

• COMPRESSION

• DB_UNIQUE_NAME

• DELAY

• ENCRYPTION

• GROUP

• LOCATION and SERVICE (LOCATION is not supported for LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31)

• MANDATORY (not supported for LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31)

• MAX_CONNECTIONS

• MAX_FAILURE

• NET_TIMEOUT

• NOREGISTER

• PRIORITY

• REOPEN

• SYNC and ASYNC (SYNC is not supported for LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31)

• TEMPLATE

• VALID_FOR

Usage Notes

• Each database in an Oracle Data Guard configuration typically has one destination with the LOCATION attribute for the archival of the online and standby redo logs and one destination with the REMOTE attribute for every other database in the configuration.

• If configured, each LOG_ARCHIVE_DEST_1 through LOG_ARCHIVE_DEST_10 destination must contain either a LOCATION or SERVICE attribute to specify a local disk directory or a remotely accessed database, respectively. Each LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31 destination must contain a SERVICE attribute.

  All other attributes are optional.

• LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31 can only be used when the COMPATIBLE initialization parameter is set to 11.2.0.0 or later.

Note:

Several attributes of the LOG_ARCHIVE_DEST_n initialization parameter have been deprecated. These attributes are supported for backward compatibility only and are documented in the Oracle Database Reference.

See Also:

Redo Transport Services for more information about defining LOG_ARCHIVE_DEST_n destinations and setting up redo transport services

17.1 AFFIRM and NOAFFIRM

The AFFIRM and NOAFFIRM attributes control whether a redo transport destination acknowledges received redo data before or after writing it to the standby redo log.

Definitions of each option are as follows:

• AFFIRM—specifies that a redo transport destination acknowledges received redo data after writing it to the standby redo log.

• NOAFFIRM—specifies that a redo transport destination acknowledges received redo data before writing it to the standby redo log.

Category	AFFIRM	NOAFFIRM
Data type	Keyword	Keyword
Valid values	Not applicable	Not applicable
Default Value	Not applicable	Not applicable
Requires attributes	SERVICE	SERVICE
Conflicts with attributes	NOAFFIRM	AFFIRM
Corresponds to	AFFIRM column of the V$ARCHIVE_DEST view	AFFIRM column of the V$ARCHIVE_DEST view

Usage Notes

• If neither the AFFIRM nor the NOAFFIRM attribute is specified, then the default is AFFIRM when the SYNC attribute is specified and NOAFFIRM when the ASYNC attribute is specified.

• Specification of the AFFIRM attribute without the SYNC attribute is deprecated and will not be supported in future releases.

See also:

SYNC and ASYNC attributes

Example

The following example shows the AFFIRM attribute for a remote destination.

LOG_ARCHIVE_DEST_3='SERVICE=stby1 SYNC AFFIRM'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

17.2 ALTERNATE

The ALTERNATE attribute specifies an alternate archiving destination to be used when the original destination fails.

Note:

As of Oracle Database 12c Release 2 (12.2.0.1), you can expand the number of alternate archive destinations and functionality by using the GROUP and PRIORITY attributes in place of the ALTERNATE attribute for remote log archive destinations. This new method cannot be used in conjunction with the ALTERNATE attribute method. For more information, see Alternate Destinations.

The ALTERNATE attribute is reserved for configuring alternate local archiving destinations. For backwards compatibility, examples of using ALTERNATE for remote log archiving destination are provided in Using the ALTERNATE Attribute to Configure Remote Alternate Destinations.

Category	ALTERNATE=LOG_ARCHIVE_DEST_n
Data Type	String
Valid Value	A LOG_ARCHIVE_DEST_n destination, where n is a value from 1 through 10.
Default Value	None. If an alternate destination is not specified, then redo transport services do not automatically change to another destination.
Requires attributes	NoneFoot 1
Conflicts with attributes	GROUP and PRIORITYFoot 2
Corresponds to	ALTERNATE and STATUS columns of the V$ARCHIVE_DEST view

^Footnote 1

Although it is not mandatory that MAX_FAILURE be used with ALTERNATE, a nonzero MAX_FAILURE value is required for an alternate to become active. Using ALTERNATE with the default value of MAX_FAILURE (zero), does not result in any change in behavior.

^Footnote 2

If the REOPEN attribute is specified with a nonzero value, then an alternate is not activated until the number of failures is greater than or equal to the value of MAX_FAILURE, with a minimum time period between attempts equal to the value of REOPEN (in seconds).

Usage Notes

• The ALTERNATE attribute is optional. If an alternate destination is not specified, then archiving services do not automatically change to another destination if the original destination fails.

• You can specify only one alternate destination for each local LOG_ARCHIVE_DEST_n parameter (LOCATION=…).

• An alternate destination should specify a different disk location on the same local primary or standby database system, as shown in the examples below.

• To configure an alternate destination, set its LOG_ARCHIVE_DEST_STATE_n parameter to ALTERNATE.

• To manually enable an alternate destination, set its LOG_ARCHIVE_DEST_STATE_n parameter to ENABLE.

• If no enabled destinations reference an alternate destination, then the alternate destination is assumed to be deferred, because there is no automatic method of enabling the alternate destination. However, you can enable (or defer) alternate destinations at runtime using the ALTER SYSTEM statement.

• Any destination can be designated as an alternate destination, given the following restrictions:

  • At least one local destination is enabled.

  • The number of enabled destinations must meet the defined LOG_ARCHIVE_MIN_SUCCEED_DEST parameter value.

  • A destination cannot be its own alternate.

• When a destination fails, its alternate destination is enabled on the next archival operation. There is no support for enabling the alternate destination in the middle of the archival operation because that would require rereading already processed blocks.

• If an alternate destination is not specified, or if MAX_FAILURE is set to zero (the default), then archiving services do not automatically change to another destination if the original destination fails.

Examples

These examples are included to illustrate basic concepts and are not meant to be used exactly as shown. They will be different in your configuration depending on your local archiving setup.

The following example shows a sample initialization parameter file in which a local archiving destination LOG_ARCHIVE_DEST_1 automatically fails over to the alternate destination LOG_ARCHIVE_DEST_2 on the next archival operation if an error occurs, such as a write failure or an allocation failure if the device were to become full.

Example 17-1 Automatically Failing Over to an Alternate Local Destination

LOG_ARCHIVE_DEST_1='LOCATION=/disk1 MANDATORY MAX_FAILURE=1 
ALTERNATE=LOG_ARCHIVE_DEST_2'
 
LOG_ARCHIVE_DEST_STATE_1=ENABLE
 
LOG_ARCHIVE_DEST_STATE_2=ALTERNATE

LOG_ARCHIVE_DEST_2='LOCATION=/disk2 MANDATORY'

To resume archiving to the original destination, LOG_ARCHIVE_DEST_1, you must re-enable it manually. Then you must reset LOG_ARCHIVE_DEST_2 to its former alternate state to avoid having two active local archiving destinations. To do this, set the LOG_ARCHIVE_DEST_STATE_n parameters back to their original values, as follows:

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_1=ENABLE

ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2=ALTERNATE

You can automate this fallback mechanism. Pair the original destination and the alternate destination by specifying an ALTERNATE attribute that points back to the preferred destination, as shown in the sample initialization parameter file in Example 17-2.

Example 17-2 Automatic Local Alternate Fallback

LOG_ARCHIVE_DEST_1='LOCATION=/disk1 MANDATORY MAX_FAILURE=1 
ALTERNATE=LOG_ARCHIVE_DEST_2'
 
LOG_ARCHIVE_DEST_STATE_1=ENABLE
 
LOG_ARCHIVE_DEST_STATE_2=ALTERNATE

LOG_ARCHIVE_DEST_2='LOCATION=/disk2 MANDATORY 
ALTERNATE=LOG_ARCHIVE_DEST_1'

If LOG_ARCHIVE_DEST_1 becomes available again, then Oracle Data Guard automatically sets it to become the active local archiving destination and resets LOG_ARCHIVE_DEST_2 as its alternate.

17.3 COMPRESSION

The COMPRESSION attribute is used to specify whether redo data is compressed before transmission to a redo transport destination.

Note:

Redo transport compression is a feature of the Oracle Advanced Compression option. You must purchase a license for this option before using the redo transport compression feature.

Category	COMPRESSION=[ENABLE | DISABLE | ZLIB | LZO]
Data Type	Boolean
Valid values	ENABLE, DISABLE, ZLIB, or LZO
Default value	DISABLE
Requires attributes	None
Conflicts with attributes	None
Corresponds to	COMPRESSION column of the V$ARCHIVE_DEST view

Usage Notes

• The ENABLE option enables compression and uses the ZLIB compression algorithm by default.

• The COMPRESSION attribute is optional. If it is not specified, the default compression behavior is DISABLE.

• For Oracle Data Guard SYNC connection strings that also use the Oracle Data Guard COMPRESSION attribute, be sure the SQLNET.COMPRESSION configuration parameter is set to disabled (set to off) in the sqlnet.ora file. See Oracle Database Net Services Reference for more information about the SQLNET.COMPRESSION parameter.

Example

The following example shows the COMPRESSION attribute with the LOG_ARCHIVE_DEST_n parameter. Since the ENABLE option is specified, the ZLIB compression algorithm is used.

LOG_ARCHIVE_DEST_3='SERVICE=denver SYNC COMPRESSION=ENABLE'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

17.4 DB_UNIQUE_NAME

The DB_UNIQUE_NAME attribute specifies a unique name for the database at this destination.

Category	DB_UNIQUE_NAME=name
Data Type	String
Valid values	The name must match the value that was defined for this database with the DB_UNIQUE_NAME parameter.
Default value	None
Requires attributes	None
Conflicts with attributes	None
Corresponds to	DB_UNIQUE_NAME column of the V$ARCHIVE_DEST view

Usage Notes

• This attribute is optional if:

  • The LOG_ARCHIVE_CONFIG=DG_CONFIG initialization parameter is not specified.

  • This is a local destination (specified with the LOCATION attribute).

• This attributes is required if the LOG_ARCHIVE_CONFIG=DG_CONFIG initialization parameter is specified and if this is a remote destination (specified with the SERVICE attribute).

• Use the DB_UNIQUE_NAME attribute to clearly identify the relationship between a primary and standby databases. This attribute is particularly helpful if there are multiple standby databases in the Oracle Data Guard configuration.

• The name specified by the DB_UNIQUE_NAME must match one of the DB_UNIQUE_NAME values in the DG_CONFIG list. Redo transport services validate that the DB_UNIQUE_NAME attribute of the database at the specified destination matches the DB_UNIQUE_NAME attribute or the connection to that destination is refused.

• The name specified by the DB_UNIQUE_NAME attribute must match the name specified by the DB_UNIQUE_NAME initialization parameter of the database identified by the destination.

Example

In the following example, the DB_UNIQUE_NAME parameter specifies boston (DB_UNIQUE_NAME=boston), which is also specified with the DB_UNIQUE_NAME attribute on the LOG_ARCHIVE_DEST_1 parameter. The DB_UNIQUE_NAME attribute on the LOG_ARCHIVE_DEST_2 parameter specifies the chicago destination. Both boston and chicago are listed in the LOG_ARCHIVE_CONFIG=DG_CONFIG parameter.

DB_UNIQUE_NAME=boston
LOG_ARCHIVE_CONFIG='DG_CONFIG=(chicago,boston,denver)'
LOG_ARCHIVE_DEST_1='LOCATION=/arch1/ 
  VALID_FOR=(ALL_LOGFILES,ALL_ROLES) 
  DB_UNIQUE_NAME=boston'
LOG_ARCHIVE_DEST_2='SERVICE=Sales_DR 
  VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) 
  DB_UNIQUE_NAME=chicago'

17.5 DELAY

The DELAY attribute specifies a minimum time lag between when redo data from the primary site is archived on a standby site and when the archived redo log file is applied to the standby database or any standbys cascaded from it.

Category	DELAY[=minutes]
Data Type	Numeric
Valid values	>=0 minutes
Default Value	30 minutes
Requires attributes	SERVICE
Conflicts with attributes	LOCATION, VALID_FOR=(*,STANDBY_ROLE)
Corresponds to	DELAY_MINS and DESTINATION columns of the V$ARCHIVE_DEST view

Usage Notes

• The DELAY attribute is optional. By default there is no delay.

• The DELAY attribute indicates the archived redo log files at the standby destination are not available for recovery until the specified time interval has expired. The time interval is expressed in minutes, and it starts when the redo data is successfully transmitted to, and archived at, the standby site.

• The DELAY attribute may be used to protect a standby database from corrupted or erroneous primary data. However, there is a tradeoff because during failover it takes more time to apply all of the redo up to the point of corruption.

• The DELAY attribute does not affect the transmittal of redo data to a standby destination.

• If you have real-time apply enabled, then any delay that you set is ignored.

• Changes to the DELAY attribute take effect the next time redo data is archived (after a log switch). In-progress archiving is not affected.

• You can override the specified delay interval at the standby site, as follows:

  • For a physical standby database:

    SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE NODELAY;
    

  • For a logical standby database:

    SQL> ALTER DATABASE START LOGICAL STANDBY APPLY NODELAY;
    

• The DELAY value that a cascaded standby uses is the value that was set for the LOG_ARCHIVE_DEST_n parameter on the primary that shipped the redo to the cascading standby.

See Also:

Oracle Database SQL Language Reference for more information about these ALTER DATABASE statements

Example

You can use the DELAY attribute to set up a configuration where multiple standby databases are maintained in varying degrees of synchronization with the primary database. However, this protection incurs some overhead during failover, because it takes Redo Apply more time to apply all the redo up to the corruption point.

For example, assume primary database A has standby databases B and C. Standby database B is set up as the disaster recovery database and therefore has no time lag. Standby database C is set up with a 2-hour delay, which is enough time to allow user errors to be discovered before they are propagated to the standby database.

The following example shows how to specify the DELAY attribute for this configuration:

LOG_ARCHIVE_DEST_1='LOCATION=/arch/dest MANDATORY'
LOG_ARCHIVE_DEST_STATE_1=ENABLE
LOG_ARCHIVE_DEST_2='SERVICE=stbyB SYNC AFFIRM'
LOG_ARCHIVE_DEST_STATE_2=ENABLE
LOG_ARCHIVE_DEST_3='SERVICE=stbyC DELAY=120'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

Note:

Alternatively, you can use Flashback Database to revert the database to a point-in-time or SCN in a different database incarnation as long as there is sufficient flashback log data. Using Flashback Database is described in Oracle Database Backup and Recovery User's Guide.

17.6 ENCRYPTION

The ENCRYPTION attribute is used to specify whether redo data is encrypted before transmission to a Zero Data Loss Recovery Appliance (Recovery Appliance).

Note:

Redo transport encryption is allowed only for connections to a Recovery Appliance. Attempting to configure encryption on a log archive destination other than a Recovery Appliance results in an error.

Category	ENCRYPTION=ENABLE or DISABLE
Data type	Boolean
Valid values	ENABLE or DISABLE
Default value	DISABLE
Requires attributes	SERVICE
Conflicts with attributes	COMPRESSION, SYNC, LOCATION, and MAX_CONNECTIONS
Corresponds to	ENCRYPTION column of the V$ARCHIVE_DEST view

Usage Notes

• The ENCRYPTION attribute is optional. If it is not specified, then the default encryption behavior is DISABLE.

• To use the ENCRYPTION attribute, you must set the COMPATIBLE initialization parameter to 11.2.0.4 or higher on the protected database.

Example

The following example shows the ENCRYPTION attribute specified on the LOG_ARCHIVE_DEST_n parameter.

LOG_ARCHIVE_DEST_3='SERVICE=denver ENCRYPTION=ENABLE'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

See Also:

• Zero Data Loss Recovery Appliance Administrator's Guide for more information about redo encryption using the LOG_ARCHIVE_DEST_n parameter

• Oracle Database Advanced Security Guide for more information about transparent data encryption

17.7 GROUP

The GROUP attribute is used to specify membership in a specific collection of log archive destinations.

Groups are numbered 1 through 8. The default group (GROUP=0) is special in that it cannot be assigned. The default group is populated with all destinations that are not explicitly assigned to a group.

Category	GROUP=integer
Data Type	Integer
Valid Value	1 through 8
Default Value	0
Requires Attributes	SERVICE
Conflicts with Attributes	ALTERNATE
Corresponds to	Not applicable

Usage Notes

• None

Examples

The following example is given to illustrate basic concepts and is not meant to be used exactly as shown. Depending on your configuration, there may be other parameters, such as DB_UNIQUE_NAME, that are required.

LOG_ARCHIVE_DEST_1='SERVICE=FS1 GROUP=1'
LOG_ARCHIVE_DEST_2='SERVICE=FS2 GROUP=1'
LOG_ARCHIVE_DEST_3='SERVICE=FS3 GROUP=2'
LOG_ARCHIVE_DEST_4='SERVICE=FS4 GROUP=2'

See Also:

• Assigning Log Archive Destinations to a Group

17.8 LOCATION and SERVICE

Each destination must specify either the LOCATION or the SERVICE attribute to identify either a local disk directory or a remote database destination where redo transport services can transmit redo data.

LOG_ARCHIVE_DEST_1 through LOG_ARCHIVE_DEST_10 destinations can contain either a LOCATION attribute or a SERVICE attribute.

LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31 destinations can only contain a SERVICE attribute.

Category	LOCATION=local_disk_directory or USE_DB_RECOVERY_FILE_DEST	SERVICE=net_service_name
Data type	String value	String value
Valid values	Not applicable	Not applicable
Default Value	None	None
Requires attributes	Not applicable	Not applicable
Conflicts with attributes	SERVICE, DELAY, NOREGISTER, SYNC, ASYNC, NET_TIMEOUT, AFFIRM,NOAFFIRM, COMPRESSION, MAX_CONNECTIONS	LOCATION
Corresponds to	DESTINATION and TARGET columns of the V$ARCHIVE_DEST view	DESTINATION and TARGET columns of the V$ARCHIVE_DEST view

Usage Notes

• Either the LOCATION or the SERVICE attribute must be specified. There is no default.

• The LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31 parameters do not support the LOCATION attribute.

• If you are specifying multiple attributes, specify the LOCATION or SERVICE attribute first in the list of attributes.

• You must specify at least one local disk directory with the LOCATION attribute. This ensures that local archived redo log files are accessible if media recovery of a database becomes necessary. You can specify up to thirty additional local or remote destinations.

• For the LOCATION attribute, you can specify one of the following:

  • LOCATION= local_disk_directory

    This specifies a unique directory path name for a disk directory on the system that hosts the database. This is the local destination for archived redo log files.

  • LOCATION=USE_DB_RECOVERY_FILE_DEST

    To configure a fast recovery area, specify the directory or Oracle Storage Manager disk group to serve as the fast recovery area using the DB_RECOVERY_FILE_DEST initialization parameter.

• When you specify a SERVICE attribute:

  • You identify remote destinations by specifying the SERVICE attribute with a valid Oracle Net service name (SERVICE= net_service_name) that identifies the remote Oracle database instance to which the redo data is sent.

    The Oracle Net service name that you specify with the SERVICE attribute is translated into a connection descriptor that contains the information necessary for connecting to the remote database.

    See Also:

    Oracle Database Net Services Administrator's Guide for details about setting up Oracle Net service names

  • Transmitting redo data to a remote destination requires a network connection and an Oracle database instance associated with the remote destination to receive the incoming redo data.

• To verify the current settings for LOCATION and SERVICE attributes, query the V$ARCHIVE_DEST fixed view:

  • The TARGET column identifies if the destination is local or remote to the primary database.

  • The DESTINATION column identifies the values that were specified for a destination. For example, the destination parameter value specifies the Oracle Net service name identifying the remote Oracle instance where the archived redo log files are located.

Examples

The following example shows how to specify the LOCATION attribute:

LOG_ARCHIVE_DEST_2='LOCATION=/disk1/oracle/oradata/payroll/arch/'
LOG_ARCHIVE_DEST_STATE_2=ENABLE

The following example shows how to specify the SERVICE attribute:

LOG_ARCHIVE_DEST_3='SERVICE=stby1'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

17.9 MANDATORY

The MANDATORY attribute specifies that filled online log files must be successfully archived to the destination before they can be reused.

Category	MANDATORY
Data type	Keyword
Valid values	Not applicable
Default value	Not applicable
Requires attributes	Not applicable
Conflicts with attributes	Optional
Corresponds to	BINDING column of the V$ARCHIVE_DEST view

Usage Notes

• The LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31 parameters do not support the MANDATORY attribute.

• If MANDATORY is not specified, then, by default, the destination is considered to be optional.

  At least one destination must succeed, even if all destinations are optional. If archiving to an optional destination fails, the online redo log file is still available for reuse and may be overwritten eventually. However, if the archival operation of a mandatory destination fails, online redo log files cannot be overwritten.

• The LOG_ARCHIVE_MIN_SUCCEED_DEST=n parameter (where n is an integer from 1 to 10) specifies the number of destinations that must archive successfully before online redo log files can be overwritten.

  All MANDATORY destinations and optional local destinations contribute to satisfying the LOG_ARCHIVE_MIN_SUCCEED_DEST=n count. If the value set for the LOG_ARCHIVE_MIN_SUCCEED_DEST parameter is met, the online redo log file is available for reuse. For example, you can set the parameter as follows:

  # Database must archive to at least two locations before 
  # overwriting the online redo log files.
  LOG_ARCHIVE_MIN_SUCCEED_DEST = 2 
  

• You must have at least one local destination, which you can declare MANDATORY or leave as optional.

  At least one local destination is operationally treated as mandatory, because the minimum value for the LOG_ARCHIVE_MIN_SUCCEED_DEST parameter is 1.

• The failure of any mandatory destination makes the LOG_ARCHIVE_MIN_SUCCEED_DEST parameter irrelevant.

• The LOG_ARCHIVE_MIN_SUCCEED_DEST parameter value cannot be greater than the number of mandatory destinations plus the number of optional local destinations.

• The BINDING column of the V$ARCHIVE_DEST fixed view specifies how failure affects the archival operation

Example

The following example shows the MANDATORY attribute:

LOG_ARCHIVE_DEST_1='LOCATION=/arch/dest MANDATORY'
LOG_ARCHIVE_DEST_STATE_1=ENABLE
LOG_ARCHIVE_DEST_3='SERVICE=denver MANDATORY'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

17.10 MAX_CONNECTIONS

The MAX_CONNECTIONS attribute enables multiple network connections to be used when sending an archived redo log file to a redo transport destination.

Using multiple network connections can improve redo transport performance over high-latency network links.

Note:

The MAX_CONNECTIONS parameter has been deprecated as of Oracle Database 18c and is maintained for backward compatibility only.

Category	Description
Data type	Integer
Valid values	1 to 20
Default value	1
Requires attributes	None
Conflicts with attributes	None
Corresponds to	MAX_CONNECTIONS column of the V$ARCHIVE_DEST view of the primary database

Usage Notes

• The MAX_CONNECTIONS attribute is optional. If it is specified, it is only used when redo transport services use ARCn processes for archival.

  • If MAX_CONNECTIONS is set to 1 (the default), redo transport services use a single ARCn process to transmit redo data to the remote destination.

  • If MAX_CONNECTIONS is set to a value greater than 1, redo transport services use multiple ARCn processes to transmit redo in parallel to archived redo log files at the remote destination. Each archiver (ARCn) process uses a separate network connection.

• With multiple ARCn processes, redo transmission occurs in parallel, thus increasing the speed at which redo is transmitted to the remote destination.

• Redo that is received from an ARCn process is written directly to an archived redo log file. Therefore, it cannot be applied in real-time as it is received.

• The actual number of archiver processes in use at any given time may vary based on the archiver workload and the value of the LOG_ARCHIVE_MAX_PROCESSES initialization parameter. For example, if the total of MAX_CONNECTIONS attributes on all destinations exceeds the value of LOG_ARCHIVE_MAX_PROCESSES, then Oracle Data Guard uses as many ARCn processes as possible, but the number may be less than what is specified by the MAX_CONNECTIONS attribute.

• When using multiple ARCn processes in an Oracle RAC environment, configure the primary instance to transport redo data to a single standby database instance. If redo transport services are not configured as such, then archival returns to the default behavior for remote archival, which is to transport redo data using a single ARCn process.

Example

The following example shows the MAX_CONNECTIONS attribute:

LOG_ARCHIVE_DEST_1='LOCATION=/arch/dest'
LOG_ARCHIVE_DEST_STATE_1=ENABLE
LOG_ARCHIVE_DEST_3='SERVICE=denver MAX_CONNECTIONS=3'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

17.11 MAX_FAILURE

The MAX_FAILURE attribute controls the consecutive number of times at a log switch that redo transport services attempts to reestablish communication and transmit redo data to a failed destination before the primary database gives up on the destination.

Category	MAX_FAILURE=count
Data type	Numeric
Valid value	>=0
Default value	For default group destinations the default value is 0. For non-default log archive destination group destinations, the default value is 1.
Requires attributes	REOPEN
Conflicts with attributes	None
Corresponds to	MAX_FAILURE, FAILURE_COUNT, and REOPEN_SECS columns of the V$ARCHIVE_DEST view

Usage Notes for MAX_FAILURE

At certain intervals, archive destinations will be checked to determine if they need to be activated. Following are the scenarios in which archive destinations are checked:

• Standalone archive destination, with no alternate location set

  If an archive destination is configured using LOG_ARCHIVE_DEST_n, and no ALTERNATE attribute is set:

  • If MAX_FAILURE is set to 1, no attempts are made to reactivate this archive destination when it fails.
  • If MAX_FAILURE > 1, reactivation attempts are made until the number of consecutive failures is equal to the value of MAX_FAILURE. After this number is reached, no further attempts are made to reactivate the archive destination.
  • If MAX_FAILURE is 0, reactivation attempts are continuous.

• Pair of archive destinations, with each being the alternate location for the other

  Consider two archive destinations configured using the LOG_ARCHIVE_DESTINATION_1 and LOG_ARCHIVE_DESTINATION_2 parameters. The ALTERNATE attribute for the LOG_ARCHIVE_DESTINATION_1 parameter is set to LOG_ARCHIVE_DESTINATION_2 and that for LOG_ARCHIVE_DESTINATION_2 is set to LOG_ARCHIVE_DESTINATION_1. The state of the preferred destination is set to ENABLE and the other archive destination is set to ALTERNATE.

  • If the value of MAX_FAILURE for the preferred destination is set to zero, the alternate destination is never activated.

    It is not recommended to set MAX_FAILUE to zero for the preferred destination because it disables the ability to activate the alternate destination.

  • If the value of MAX_FAILURE for the preferred destination is set to a non-zero value, the archive destination is activated after the preferred destination has MAX_FAILURE failures. At this time, the preferred destination is assigned as the alternate destination. While the preferred destination is in the ALTERNATE state, regardless of the value of REOPEN, attempts are made to reactivate the preferred destination.

  After a non-preferred alternate location is activated, its behavior is similar to a standalone archive location with the following exceptions:

  • If the preferred destination is activated during one of the reactivation attempts, the non-preferred destination will be designated to the ALTERNATE state.
  • If the non-preferred destination reaches MAX_FAILURE, then both archive destinations are disabled and no further reactivation attempts are made.

• Chain of archive destinations

  Consider an example of three archive destinations configured using the LOG_ARCHIVE_DEST_1, LOG_ARCHIVE_DEST_2, and LOG_ARCHIVE_DEST_3 parameters. LOG_ARCHIVE_DEST_2 is the alternate destination for LOG_ARCHIVE_DEST_1 and LOG_ARCHIVE_DEST_3 is the alternate location for LOG_ARCHIVE_DEST_2. LOG_ARCHIVE_DEST_3 has no alternate location.

  The value of the MAX_FAILURE attribute for LOG_ARCHIVE_DEST_1 and LOG_ARCHIVE_DEST_2 must be set to a non-zero value. Otherwise, if LOG_ARCHIVE_DEST_1 or LOG_ARCHIVE_DEST_2 fails, its alternate destination is never activated because with MAX_FAILURE being zero, the destination is continuously checked for reactivation. Once the MAX_FAILURE value is reached for LOG_ARCHIVE_DEST_1, LOG_ARCHIVE_DEST_2 is activated. When LOG_ARCHIVE_DEST_2 reaches MAX_FAILURE, then LOG_ARCHIVE_DEST_3 is activated. The behavior for LOG_ARCHIVE_DEST_3 is the same as that for standalone archive destinations.

• Archive destinations in a group

  Consider a log archive group containing multiple log archive destinations. Each archive destination has a priority between 1 and 8. All archive destinations in the group must have MAX_FAILURE attribute set to a non-zero value. The alternate destination with the highest priority is activated first. If there are multiple alternate destinations with the highest available priority, one of them is selected.

  If priority 8 becomes the highest priority functioning archive destination, then all archive destinations with priority 8 are activated.

  If the currently active destination fails, the destination with the highest priority among the remaining destinations is activated, with the special case if destinations with priority 8 are activated.

  Regardless of the value set for the REOPEN attribute, all alternate destinations that are at a higher priority than the currently-active archive destination are checked for reactivation at regular intervals. If a higher priority archive destination becomes functional, that archive destination is activated and the currently active archive destination will be put in the ALTERNATE state.

Usage Notes for MAX_FAILURE in Oracle Database 12c Release 2 (12.2)

• For redo destinations that use the new GROUP and PRIORITY attributes, if the error count reaches the value specified for the MAX_FAILURE attribute, then the destination enters the ERROR state where it remains until it is found to be accessible. It is checked periodically depending on the value specified for the REOPEN attribute.

• For default destinations in log archive groups (those redo destinations that do not use the new GROUP and PRIORITY attributes), the behavior of the MAX_FAILURE attribute is the same as it is in Oracle Database 12c Release 1 (12.1.0.1)

Example

The following example allows redo transport services to try reconnecting up to three consecutive times at log switch to the failed destination, as long as each log switch is more than 5 seconds apart. If the archival operation fails after the third attempt, then the destination is treated as if the REOPEN attribute was not specified and the destination is marked as permanently failed until reset.

LOG_ARCHIVE_DEST_1='LOCATION=/arc_dest REOPEN=5 MAX_FAILURE=3'
LOG_ARCHIVE_DEST_STATE_1=ENABLE

17.12 NET_TIMEOUT

The NET_TIMEOUT attribute specifies the number of seconds that the LGWR background process blocks waiting for a redo transport destination to acknowledge redo data sent to it.

If an acknowledgement is not received within NET_TIMEOUT seconds, an error is logged and the redo transport session to that destination is terminated.

Category	NET_TIMEOUT=seconds
Data type	Numeric
Valid values	1Foot 3 to 1200
Default value	30 seconds
Requires attributes	SYNC
Conflicts with attributes	ASYNC (If you specify the ASYNC attribute, redo transport services ignores it; no error is returned.)
Corresponds to	NET_TIMEOUT column of the V$ARCHIVE_DEST view of the primary database

^Footnote 3

Although a minimum value of 1 second is allowed, Oracle recommends a minimum value of 8 to 10 seconds to avoid disconnecting from the standby database due to transient network errors.

Usage Notes

• The NET_TIMEOUT attribute is optional. However, if you do not specify the NET_TIMEOUT attribute it is set to 30 seconds, but the primary database can potentially stall. To avoid this situation, specify a small, nonzero value for the NET_TIMEOUT attribute so the primary database can continue operation after the user-specified timeout interval expires when waiting for status from the network server.

• As of Oracle Database 12c Release 12.2 (12.2.0.1), there is a new database initialization parameter, DATA_GUARD_SYNC_LATENCY, which is global for all synchronous standby destinations. It defines the maximum amount of time (in seconds) that the primary database may wait before disconnecting subsequent destinations after at least one synchronous standby has acknowledged receipt of the redo. See Oracle Database Reference.

Example

The following example shows how to specify a 10-second network timeout value on the primary database with the NET_TIMEOUT attribute.

LOG_ARCHIVE_DEST_2='SERVICE=stby1 SYNC NET_TIMEOUT=10'
LOG_ARCHIVE_DEST_STATE_2=ENABLE

17.13 NOREGISTER

The NOREGISTER attribute indicates that the location of the archived redo log file should not be recorded at the corresponding destination.

Category	NOREGISTER
Data type	Keyword
Valid values	Not applicable
Default value	Not applicable
Requires attributes	SERVICE
Conflicts with attributes	LOCATION
Corresponds to	DESTINATION and TARGET columns of the V$ARCHIVE_DEST view

Usage Notes

• The NOREGISTER attribute is optional if the standby database destination is a part of an Oracle Data Guard configuration.

• The NOREGISTER attribute is required if the destination is not part of an Oracle Data Guard configuration.

• This attribute pertains to remote destinations only. The location of each archived redo log file is always recorded in the primary database control file.

• This attribute must not be used in an Oracle Data Guard configuration that has no downstream GoldenGate mining setup. Using NOREGISTER in this scenario may cause problems during switchover operations.

Example

The following example shows the NOREGISTER attribute:

LOG_ARCHIVE_DEST_5='NOREGISTER'

17.14 PRIORITY

The PRIORITY attribute is used to specify preference within a collection of log archive destinations.

Priorities are numbered 1 through 8. A lower value represents a higher priority. The lowest priority (PRIORITY=8) is special in the sense that if that priority is active then all destinations at that priority are made active. If any higher priority destination returns to service, then that destination is made active and all low priority destinations are made inactive.

Category	Priority=integer
Data Type	Integer
Valid Value	1 through 8
Default Value	1
Requires attributes	SERVICE
Conflicts with attributes	ALTERNATE
Corresponds to	Not applicable

Usage Notes

• The PRIORITY attribute is always used in conjunction with the GROUP attribute to provide an orderly enabling and fallback of members (redo destinations) of the group.

Example

The following example is given to illustrate basic concepts and is not meant to be used exactly as shown. Depending on your configuration, there may be other parameters, such as DB_UNIQUE_NAME, that are required. A sample log archive destination setup that defines priorities is as follows:

LOG_ARCHIVE_DEST_1='SERVICE=FS1 SYNC GROUP=1 PRIORITY=1'
LOG_ARCHIVE_DEST_2='SERVICE=FS2 SYNC GROUP=1 PRIORITY=1'
LOG_ARCHIVE_DEST_3='SERVICE=FS3 ASYNC GROUP=1 PRIORITY=2'
LOG_ARCHIVE_DEST_4='SERVICE=TS ASYNC GROUP=1 PRIORITY=3'

This declaration results in the following behavior:

• The primary ships to either of two preferred far sync instances, FS1 or FS2.

• If both FS1 and FS2 become unavailable, then the primary ships to FS3 (in this case via ASYNC).

• If either FS1 or FS2 become available while the primary is shipping to FS3, then the primary fails back to the available preferred log archive destination.

• If all three higher priority log archive destinations fail, the primary begins shipping to TS (Terminal Standby). While shipping to TS, if FS1, FS2, or FS3 become available, then the primary switches to the newly available higher priority destination.

See Also:

• Assigning Priorities to Log Archive Destinations in a Group

17.15 REOPEN

The REOPEN attribute specifies the minimum number of seconds before redo transport services try to reopen a failed destination.

Category	REOPEN [=seconds]
Data Type	Numeric
Valid values	>=0 seconds
Default Value	300 seconds
Requires attributes	None
Conflicts with attributes	Not applicable
Corresponds to	REOPEN_SECS and MAX_FAILURE columns of the V$ARCHIVE_DEST view

Usage Notes

• The REOPEN attribute is optional.

• Redo transport services attempt to reopen failed destinations at log switch time.

• Redo transport services check if the time of the last error plus the REOPEN interval is less than the current time. If it is, redo transport services attempt to reopen the destination.

• REOPEN applies to all errors, not just connection failures. These errors include, but are not limited to, network failures, disk errors, and quota exceptions.

• If you specify REOPEN for an optional destination, then it is possible for the Oracle database to overwrite online redo log files if there is an error. If you specify REOPEN for a MANDATORY destination, then redo transport services stall the primary database when it is not possible to successfully transmit redo data. When this situation occurs, consider the following options:

  • Change the destination by deferring the destination, specifying the destination as optional, or changing the SERVICE attribute value.

  • Specify an alternate destination.

  • Disable the destination.

Example

The following example shows the REOPEN attribute.

LOG_ARCHIVE_DEST_3='SERVICE=stby1 MANDATORY REOPEN=60'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

17.16 SYNC and ASYNC

The SYNC and ASYNC attributes specify whether the synchronous (SYNC) or asynchronous (ASYNC) redo transport mode is to be used.

Category	SYNC	ASYNC
Data type	Keyword	Keyword
Valid values	Not applicable	Not applicable
Default value	Not applicable	None
Requires attributes	None	None
Conflicts with attributes	ASYNC, LOCATION	SYNC, LOCATION
Corresponds to	TRANSMIT_MODE column of the V$ARCHIVE_DEST view	TRANSMIT_MODE column of the V$ARCHIVE_DEST view

Usage Notes

• The LOG_ARCHIVE_DEST_11 through LOG_ARCHIVE_DEST_31 parameters do not support the SYNC attribute.

• The redo data generated by a transaction must have been received by every enabled destination that has the SYNC attribute before that transaction can commit.

• On primary databases and logical standbys, destinations 1 through 10 default to ASYNC (real-time cascading).

  On physical standbys, snapshot standbys, and far sync instances, destinations 1 through 10 default to ARCH transport mode. (Note that the ARCH attribute is deprecated; the use of ARCH in this situation simply indicates non-real-time cascading.)

  Destinations 11 through 31 always default to ASYNC.

See Also:

• Oracle Database Reference for more information about LOG_ARCHIVE_DEST_n deprecated attributes

Example

The following example shows the SYNC attribute with the LOG_ARCHIVE_DEST_n parameter.

LOG_ARCHIVE_DEST_3='SERVICE=stby1 SYNC'
LOG_ARCHIVE_DEST_STATE_3=ENABLE

17.17 TEMPLATE

The TEMPLATE attribute defines a directory specification and format template for names of archived redo log files at the destination.

The template is used to generate a filename that is different from the default filename format defined by the LOG_ARCHIVE_FORMAT initialization parameter at the redo destination.

Category	TEMPLATE=filename_template_%t_%s_%r
Data Type	String value
Valid values	Not applicable
Default value	None
Requires attributes ...	SERVICE
Conflicts with attributes ...	LOCATION
Corresponds to ...	REMOTE_TEMPLATE and REGISTER columns of the V$ARCHIVE_DEST view

Usage Notes

• The TEMPLATE attribute is optional. If TEMPLATE is not specified, archived redo logs are named using the value of the LOG_ARCHIVE_FORMAT initialization parameter.

• The TEMPLATE attribute overrides the LOG_ARCHIVE_FORMAT initialization parameter setting at the remote archival destination.

• The TEMPLATE attribute is valid only with remote destinations (specified with the SERVICE attribute).

• The value you specify for filename_template must contain the %s, %t, and %r directives described in Table 17-1.

  Table 17-1 Directives for the TEMPLATE Attribute

  Directive	Description
  %t	Substitute the instance thread number.
  %T	Substitute the instance thread number, zero filled.
  %s	Substitute the log file sequence number.
  %S	Substitute the log file sequence number, zero filled.
  %r	Substitute the resetlogs ID.
  %R	Substitute the resetlogs ID, zero filled.

• The filename_template value is transmitted to the destination, where it is translated and validated before creating the filename.

17.18 VALID_FOR

The VALID_FOR attribute specifies whether redo data gets written to a destination.

The following factors are considered:

• Whether the database is currently running in the primary or the standby role

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

Category	VALID_FOR=(redo_log_type, database_role)
Data Type	String value
Valid values	Not applicable
Default Value	VALID_FOR=(ALL_LOGFILES, ALL_ROLES)
Requires attributes	None
Conflicts with attributes	None
Corresponds to	VALID_NOW, VALID_TYPE, and VALID_ROLE columns in the V$ARCHIVE_DEST view

Usage Notes

• The VALID_FOR attribute is optional. However, Oracle recommends that the VALID_FOR attribute be specified for each redo transport destination at each database in an Oracle Data Guard configuration so that redo transport continues after a role transition to any standby database in the configuration.

• To configure these factors for each LOG_ARCHIVE_DEST_n destination, you specify this attribute with a pair of keywords: VALID_FOR=(redo_log_type,database_role):

  • The redo_log_type keyword identifies the destination as valid for archiving one of the following:

    • ONLINE_LOGFILE—This destination is valid only when archiving online redo log files.

    • STANDBY_LOGFILE—This destination is valid only when archiving standby redo log files.

    • ALL_LOGFILES— This destination is valid when archiving either online redo log files or standby redo log files.

  • The database_role keyword identifies the role in which this destination is valid for archiving:

    • PRIMARY_ROLE—This destination is valid only when the database is running in the primary role.

    • STANDBY_ROLE—This destination is valid only when the database is running in the standby role.

    • ALL_ROLES—This destination is valid when the database is running in either the primary or the standby role.

• If you do not specify the VALID_FOR attribute for a destination, by default, archiving online redo log files and standby redo log files is enabled at the destination, regardless of whether the database is running in the primary or the standby role. This default behavior is equivalent to setting the (ALL_LOGFILES,ALL_ROLES) keyword pair on the VALID_FOR attribute.

• The VALID_FOR attribute enables you to use the same initialization parameter file for both the primary and standby roles.

Example

The following example shows the default VALID_FOR keyword pair:

LOG_ARCHIVE_DEST_1='LOCATION=/disk1/oracle/oradata VALID_FOR=(ALL_LOGFILES, ALL_ROLES)'

When this database is running in either the primary or standby role, destination 1 archives all log files to the /disk1/oracle/oradata local directory location.