|Oracle® Data Guard Broker
11g Release 2 (11.2)
Part Number E17023-03
This preface describes the new features added to Oracle Data Guard broker in Oracle Database 11g and provides links to additional information. For information about features that were introduced in earlier releases, refer to the documentation for those releases.
This section describe the new features and enhancements that were added to Oracle Data Guard broker in Oracle Database 11g Release 2 (11.2):
Oracle Data Guard broker is fully integrated with Oracle Real Application Clusters One Node (Oracle RAC One Node).
A broker configuration can now consist of a primary database and up to 30 standby databases.
The value of an instance-specific property can be changed for all instances in one command.
Redo transport compression is no longer limited to compressing redo data only when a redo gap is being resolved. When compression is enabled for a destination, all redo data sent to that destination is compressed.
Reinstatement of logical bystanders after a physical standby or logical standby failover.
Reinstatement of bystanders after an immediate failover.
Reinstatement of the old (original) primary database after an immediate failover.
Shutting down all instances but one on a target physical standby for role changes is no longer required.
FAN/ONS (Fast Application Notification/Oracle Notification Services) notification is sent after a failover for databases configured with Oracle Clusterware and for single-instance databases registered with Oracle Restart.
FAN/AQ (Fast Application Notification/Advanced Queuing) notification is sent after a failover to a logical standby database.
Improved status and error reporting for the
SHOW CONFIGURATION and
SHOW DATABASE commands.
SHOW DATABASE command displays the apply lag and transport lag of a standby database.
Integration with Active Data Guard (automatic stop and restart of apply) when an apply instance is opened.
The broker configuration files can now reside on disks having any sector size (physical block size) up to 4KB.
Improved hang detection and resolution for broker network communications. In addition, a new configuration property,
CommunicationTimeout, enables the user to select an appropriate timeout value for their environment.
New database property,
StaticConnectIdentifier, which allows the user to specify a static connect identifier that the DGMGRL client will use to start database instances.
Protection mode upgrades from maximum availability to maximum protection no longer require a restart of the primary database.
This means that when upgrading from maximum performance mode to maximum protection mode, you can avoid a restart of the primary database by first upgrading to maximum availability. Once in maximum availability mode, you can then upgrade to maximum protection mode.
Data Recovery Adviser now uses Data Guard to suggest viable repair options for a primary database that cannot be repaired in a timely manner.
This section describe the new features and enhancements that were added to Oracle Data Guard broker in Oracle Database 11g Release 1 (11.1):
Fast-start failover enhancements
The following features increase the flexibility and manageability of customers' disaster-recovery configurations using Data Guard:
Fast-start failover for a configuration operating in maximum performance mode
Allows fast-start failover to be enabled in a Data Guard broker configuration operating in maximum performance mode. The administrator can choose the maximum amount of data that may be lost if a fast-start failover is initiated.
DBMS_DG PL/SQL package
DBMS_DG PL/SQL package allows applications to notify the observer process to initiate a fast-start failover to the target standby database.
Fast-start failover for configurable conditions
Fast-start failover can be configured to occur when specific database conditions are detected. Certain conditions detectable through the database health-check mechanism and errors raised by the Oracle server (such as ORA errors) may be designated as conditions under which a fast-start failover should occur.
After a failover, the observer automatically attempts to reinstate bystander standby databases.
DBMS_DG PL/SQL package in Oracle Database PL/SQL Packages and Types Reference
The following enhancements make it possible to use the Data Guard broker in a wider variety of disaster-recovery configurations:
Support for snapshot standby databases
See Also:The DGMGRL CONVERT DATABASE command
Support for Redo Apply on physical standby databases opened for read
Improved support for redo transport options. Enables the administrator to specify a connect identifier for Redo Transport Services.
Elimination of database downtime when changing the protection mode to and from maximum availability and maximum performance
Allow a primary or logical standby database in a Data Guard Broker configuration to be mounted without having to be opened automatically
The DGMGRL client
ADD DATABASE command can import a pre-configured service attribute from a
n parameter when adding a standby database to the configuration.
Simplification of the database states managed by the broker. A primary database can be in either the TRANSPORT-OFF or TRANSPORT-ON state. A standby database can be in either the APPLY-OFF or APPLY-ON state.
Compression of redo traffic over the network in a Data Guard configuration
This feature improves the network bandwidth utilization in a Data Guard configuration by compressing archived redo logs as they are transmitted over the network to standby databases, when the log is sent to satisfy a gap at a standby database.
See Also:Section 8.3.35, "RedoCompression"
Better integration with the database recovery area because you can now specify
USE_DB_RECOVERY_FILE_DEST as the value for the
StandbyArchiveLocation instance-specific properties.
New Data Guard command-line interface (DGMGRL) commands include:
CONVERT DATABASE TO [SNAPSHOT | PHYSICAL] STANDBY
DISABLE FAST_START FAILOVER CONDITION
ENABLE FAST_START FAILOVER CONDITION
SHOW FAST_START FAILOVER
New database properties include:
New configuration properties include:
The LsbyTxnConsistency database property has been renamed to
New default of
ASYNC for the
LogXptMode database property