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Oracle® Data Guard Concepts and Administration
10g Release 1 (10.1)

Part Number B10823-01
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Oracle Data Guard is the most effective solution available today to protect the core asset of any enterprise--its data, and make it available on a 24x7 basis even in the face of disasters and other calamities.

This guide describes Oracle Data Guard technology and concepts, and helps you configure and implement standby databases.

This preface contains the following topics:


Oracle Data Guard Concepts and Administration is intended for database administrators (DBAs) who administer the backup, restoration, and recovery operations of an Oracle database system.

To use this document, you should be familiar with relational database concepts and basic backup and recovery administration. You should also be familiar with the operating system environment under which you are running Oracle software.

Documentation Accessibility

Our goal is to make Oracle products, services, and supporting documentation accessible, with good usability, to the disabled community. To that end, our documentation includes features that make information available to users of assistive technology. This documentation is available in HTML format, and contains markup to facilitate access by the disabled community. Standards will continue to evolve over time, and Oracle is actively engaged with other market-leading technology vendors to address technical obstacles so that our documentation can be accessible to all of our customers. For additional information, visit the Oracle Accessibility Program Web site at

Accessibility of Code Examples in Documentation

JAWS, a Windows screen reader, may not always correctly read the code examples in this document. The conventions for writing code require that closing braces should appear on an otherwise empty line; however, JAWS may not always read a line of text that consists solely of a bracket or brace.


This document contains:

Part I, "Concepts and Administration"

Chapter 1, "Introduction to Oracle Data Guard"

This chapter offers a general overview of the Oracle Data Guard architecture.

Chapter 2, "Getting Started with Data Guard"

This chapter describes physical and logical databases in more detail and the various interfaces you can use to manage the Data Guard configuration. It also describes the operational requirements for using Data Guard and provides recommendations for setting up directory structures on standby databases.

Chapter 3, "Creating a Physical Standby Database"

This chapter explains how to create a physical standby database.

Chapter 4, "Creating a Logical Standby Database"

This chapter explains how to create a logical standby database.

Chapter 5, "Log Transport Services"

This chapter introduces log transport services. It describes the data protection modes that protect the production database against loss in the event of an unplanned outage, and it provides procedures and guidelines for configuring log transport services on a primary and standby database.

Chapter 6, "Log Apply Services"

This chapter introduces log apply services. It provides guidelines for managing log apply services for physical and logical standby databases.

Chapter 7, "Role Management"

This chapter introduces role management services. It provides information about database failover and switchover role transitions.

Chapter 8, "Managing a Physical Standby Database"

This chapter describes how to manage a physical standby database. It provides information about monitoring and responding to events that affect a standby database.

Chapter 9, "Managing a Logical Standby Database"

This chapter describes how to manage a logical standby database. It provides information about managing SQL Apply, system tuning, and tablespace management.

Chapter 10, "Data Guard Scenarios"

This chapter describes common database scenarios such as creating, recovering, failing over, switching over, configuring, and backing up standby and primary databases.

Part II, "Reference"

Chapter 11, "Initialization Parameters"

This reference chapter describes initialization parameters for each Oracle instance, including the primary database and each standby database in the Data Guard environment.

Chapter 12, "LOG_ARCHIVE_DEST_n Parameter Attributes"

This reference chapter provides syntax and examples for the attributes of the LOG_ARCHIVE_DEST_n initialization parameter.

Chapter 13, "SQL Statements Relevant to Data Guard"

This reference chapter provides SQL statements that are useful for performing operations on a Data Guard configuration.

Chapter 14, "Views Relevant to Oracle Data Guard"

This reference chapter lists views that contain useful information for monitoring the Data Guard environment. It summarizes the columns contained in each view and provides a description for each column.

Part III, "Appendixes and Glossary"

Appendix A, "Troubleshooting Data Guard"

This appendix discusses troubleshooting tips for Data Guard and standby databases.

Appendix B, "Data Guard and Real Application Clusters"

This appendix describes the primary and standby database configurations in a Real Application Clusters environment.

Appendix C, "Cascaded Redo Log Destinations"

This appendix describes how to implement cascaded redo log file destinations, whereby a standby database receives redo data from another standby database, instead of directly from the primary database.

Appendix D, "Creating a Physical Standby Database with Recovery Manager"

This appendix describes how to use Recovery Manager to create a physical standby database.

Appendix E, "Setting Archive Tracing"

This appendix describes how the LOG_ARCHIVE_TRACE parameter controls output generated by the ARCn, LGWR, and foreground processes on the primary database, and the RFS and FAL server processes on the standby database.

Appendix F, "Sample Disaster Recovery ReadMe File"

This appendix provides a sample ReadMe file that includes the kind of information that the person who is making disaster recovery decisions would need when deciding which standby database should be the target of the failover operation.

Related Documentation

Readers of Oracle Data Guard Concepts and Administration should also read:

Discussions in this book also refer you to the following guides:

If you need to upgrade existing Data Guard configurations to this Oracle release, see Oracle Database Upgrade Guide for complete instructions. In addition, refer to Oracle Database Concepts for information about other Oracle products and features that provide disaster recovery and high-availability solutions.

Also, see Oracle Streams Concepts and Administration for information about Oracle Streams and the Streams Downstream Capture Database. The Streams downstream capture process uses the Oracle Data Guard log transport services to transfer redo data to log files on a remote database where a Streams capture process captures changes in the archived redo log files at the remote destination.

Printed documentation is available for sale in the Oracle Store at

To download free release notes, installation documentation, white papers, or other collateral, please visit the Oracle Technology Network (OTN). You must register online before using OTN; registration is free and can be done at

If you already have a username and password for OTN, then you can go directly to the documentation section of the OTN Web site at


This section describes the conventions used in the text and code examples of this document. The following table describes those conventions and provides examples of their use.

Convention Meaning Example

[ ]

Brackets enclose one or more optional items. Do not enter the brackets.

DECIMAL (digits [ , precision ])

{ }

Braces enclose two or more items, one of which is required. Do not enter the braces.



A vertical bar represents a choice of two or more options within brackets or braces. Enter one of the options. Do not enter the vertical bar.




Horizontal ellipsis points indicate either:

  • That we have omitted parts of the code that are not directly related to the example
  • That you can repeat a portion of the code

CREATE TABLE ... AS subquery;

SELECT col1, col2, ... , coln FROM employees;




Vertical ellipsis points indicate that we have omitted several lines of code not directly related to the example.



Bold typeface indicates terms that are defined in the text or terms that appear in a glossary, or both.

When you specify this clause, you create an index-organized table.

UPPERCASE monospace (fixed-width font)

Uppercase monospace typeface indicates elements supplied by the system.

You can back up the database by using the BACKUP command.


lowercase monospace (fixed-width font)

Lowercase monospace typeface indicates executables, filenames, directory names, and sample user-supplied elements.

Enter sqlplus to open SQL*Plus.

Back up the datafiles and control files in the /disk1/oracle/dbs directory.

The department_id, department_name, and location_id columns are in the hr.departments table.

lowercase monospace (fixed-width font) italic

Lowercase monospace italic font represents placeholders or variables.

You can specify the parallel_clause.

Run Uold_release.SQL where old_release refers to the release you installed prior to upgrading.

monospace (fixed-width font)

Mixed-case monospace typeface indicates a Data Guard broker database property. The mixed case helps you visually differentiate a Data Guard broker property from other system-supplied elements, which are always shown in uppercase typeface.

Mixed-case monospace typeface can also indicate other programmatic elements. Enter these elements as shown.

The StandbyFileManagement property corresponds to the STANDBY_FILE_MANAGEMENT initialization parameter.

The JRepUtil class implements these methods.