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 release provides the following new features:
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.
New DBMS_DG PL/SQL package
The 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.
See Also:
The DBMS_DG PL/SQL package in Oracle Database PL/SQL Packages and Types Reference
Manageability enhancements
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 commandSupport 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 CLI ADD DATABASE command can import a pre-configured service attribute from a LOG_ARCHIVE_DEST_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 9.2.42, "RedoCompression"Better integration with the database recovery area because you can now specify USE_DB_RECOVERY_FILE_DEST as the value for the AlternateLocation and StandbyArchiveLocation database configurable 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 configurable properties include:
DGConnectIdentifier (replaces InitialConnectIdentifier)
ObserverConnectIdentifier
RedoCompression
New configuration properties include:
FastStartFailoverAutoReinstate
FastStartFailoverLagLimit
FastStartFailoverPmyShutdown
The LsbyTxnConsistency configurable database property has been renamed to LsbyPreserveCommitOrder
New default of ASYNC for the LogXptMode configurable database property
See Also:
Chapter 9, "Database Properties"