Preface

Welcome to the world of Oracle backup and recovery. This guide includes the conceptual and task-oriented information you need to:

• Understand what backup and recovery is and how it works.

• Perform backup, restore, and recovery procedures using operating system (O/S) commands.

The Oracle8i Backup and Recovery Guide contains information that describes the features and functionality of the Oracle8i Standard Edition and the Oracle8i Enterprise Edition products. The Standard Edition and Enterprise Edition have the same basic features, but several advanced features are available only with the Enterprise Edition, and some of these are optional.

See Also: Oracle8i Recovery Manager User's Guide and Reference for concepts, procedures, and reference material related to the Recovery Manager utility Oracle8i Standby Database Concepts and Administration for information about the standby database Getting to Know Oracle8i for information for the differences between Oracle8i Standard Edition and the Oracle8i Enterprise Edition and the features and options that are available to you

What's New in Oracle8i?

This section describes new features in Oracle8i.

Release 8.1.6

Oracle release 8.1.6 contains a number of improvements that provide more robust protections against the following types of data corruption:

• Logical corruptions. Logical data corruptions are typically caused by software bugs and are difficult to repair because these corruptions are in the redo stream. You can prevent most logical corruptions by enabling block checking, which can detect and roll back changes that corrupt the database. Block checking is improved in these ways:
  • Oracle checks more block types, such as rollback blocks, transaction table blocks, and segment headers.

  • Block checking is more efficient, checking more blocks without increasing system overhead.

  • Block checking is always turned on for the SYSTEM tablespace, regardless of the setting of the DB_BLOCK_CHECKING initialization parameter.

• Memory corruptions. If block checking is turned on, then DBWn performs block checking immediately before writing a block to disk. This check enables Oracle to catch some memory corruptions and automatically repair corrupted blocks.

• Physical data corruptions caused by disks or storage systems. Typically, Oracle detects these corruptions through a checksum. Oracle release 8.1.6 always performs a checksum in the SYSTEM tablespace, regardless of the DB_BLOCK_CHECKSUM parameter setting.

  If the checksum fails when Oracle reads the control file or redo logs, then Oracle rereads the data from either a different log or the same member in situations where previous Oracle releases would not reread. Consequently, Oracle has a second chance to find a good copy of the data and repair any physical data corruption.

Release 8.1.5

The following backup and recovery features are new in release 8.1.5:

• You can temporarily suspend and then resume database operations without shutting down the database (see "Making Backups in SUSPEND Mode").

• You can use transportable tablespaces to perform tablespace point-in-time recovery (TSPITR) (see "Performing TSPITR Using Transportable Tablespaces").

• The LOG_ARCHIVE_DEST_n (where n is an integer from 1 to 5) initialization parameter allows you to archive to up to 5 locations (see "Archiving Redo Logs to Multiple Locations").

Structure

Part / Chapter	Contents
PART 1	Developing a Backup and Recovery Strategy
Chapter 1, "What Is Backup and Recovery?"	Offers a general overview of backup and recovery concepts and methods.
Chapter 2, "Managing Data Structures"	Describes how to manage control files, online redo logs, and archived redo logs for backup and recovery.
Chapter 3, "Developing a Backup and Recovery Strategy"	Provides guidelines for developing a backup and recovery strategy.
PART 2	Using Operating System Commands for Backup and Recovery
Chapter 4, "Performing Operating System Backups"	Provides step-by-step instructions for performing operating system backups.
Chapter 5, "Performing Media Recovery"	Provides step-by-step instructions for performing media restore and recovery using operating system and SQL*Plus commands.
Chapter 6, "Media Recovery Scenarios"	Describes the procedures for performing media recovery in several common scenarios.
Chapter 7, "Performing Operating System Tablespace Point-in-Time Recovery"	Provides planning guidelines and step-by-step instructions for manually performing tablespace point-in-time recovery.

This book contains the following parts and chapters.

Changes to This Book

The following aspects of this manual are new in release 8.1.6:

• In release 8.1.5, all the backup and recovery documentation was located in the Oracle8i Backup and Recovery Guide. In release 8.1.6, this documentation is divided into the following books:
  • Oracle8i Backup and Recovery Guide

  • Oracle8i Recovery Manager User's Guide and Reference

  • Oracle8i Standby Database Concepts and Administration

Audience

This guide is for database administrators (DBAs) who administer the backup, restore, and recovery operations of an Oracle database system using operating system commands.

Knowledge Assumed of the Reader

Readers of this guide are assumed to be familiar with relational database concepts and basic database administration. They are also assumed to be familiar with the operating system environment under which they are running Oracle.

Conventions

This section explains the conventions used in this manual including the following:

• Text

• Recovery Manager Syntax Diagrams and Notation

• Code Examples

Text

This section explains the conventions used within the text:

UPPERCASE Characters

Uppercase text is used to call attention to tablespace names, initialization parameters, and SQL keywords.

For example, "If you create a private rollback segment, the name must be included in the ROLLBACK_SEGMENTS parameter of the initialization parameter file. You can view this information by issuing a SHOW PARAMETER statement in SQL*Plus."

Italicized Characters

Italicized words within text are book titles, new vocabulary, emphasized words, or variables in SQL or Recovery Manager syntax.

For example, "An archived redo log is an online redo log that has been copied offline. You must run your database in ARCHIVELOG mode to enable this feature. If you are using Recovery Manager, you can specify an archived redo log in a backup command by using the archivelog like '/oracle/archive/arc_*' subclause."

Bold Characters

Bold words within text are Recovery Manager keywords.

For example, "Use the Recovery Manager backup command to back up your database."

Monospaced Characters

Filenames, directories, and operating system commands appear in a monospaced font. Also, monospaced characters in text preceding a code example indicates a filename or keyword used in the sample code.

For example, "If you do not want to use a command such as the UNIX cp to perform the backup of /oracle/dbs/df1.f, then you can execute an RMAN job as follows:

run {
     allocate channel c1 type disk;
     backup datafile `/oracle/dbs/df1.f';
}

Recovery Manager Syntax Diagrams and Notation

For information about Recovery Manager syntax conventions, see the Oracle8i Recovery Manager User's Guide and Reference.

Code Examples

SQL, SQL*Plus, and Recovery Manager commands and statements appear separated from the text of paragraphs in a monospaced font. For example:

INSERT INTO emp (empno, ename) VALUES (1000, 'SMITH'); 
ALTER TABLESPACE users ADD DATAFILE 'users2.ora' SIZE 50K; 
run {
     allocate channel ch1 type disk;
     backup database;
}

When you run RMAN from the command line, the command prompt appears as RMAN>. When you issue commands from the SQL*Plus command line, the prompt appears as SQL>. These prompts are displayed in the code examples only when they are necessary to prevent confusion.

You can execute SQL, SQL*Plus, and RMAN commands in different environments on different platforms. As much as possible, this guide attempts to provide generic documentation, that is, documentation that is not specific to any operating system or interface. Nevertheless, it is sometimes necessary for illustrative purposes to show how the syntax works at the operating system level. In these cases, this book uses examples from a UNIX command-line interface and employs the % symbol to indicate the operating system prompt. For example:

% rman target / rcvcat rman/rman@inst2
RMAN> startup

How to Use This Guide

Every reader of this guide is presumed to have read:

• The beginning of the Oracle8i Concepts manual, which provides an overview of the concepts and terminology related to Oracle and a foundation for the more detailed information in this guide. The rest of the Oracle8i Concepts manual explains the Oracle architecture and features in detail.

• The chapters in the Oracle8i Administrator's Guide that deal with managing the control file, online redo logs, and archived redo logs.

You will often need to refer to the following reference guides:

• Oracle8i SQL Reference

• Oracle8i Reference

Your Comments Are Welcome

We value and appreciate your comments as an Oracle user and reader of our references. As we write, revise, and evaluate, your opinions are the most important input we receive. At the front of this reference is a reader's comment form that we encourage you to use to tell us both what you like and what you dislike about this (or other) Oracle manuals. If the form is missing, or you would like to contact us, please use the following address or fax number:

Server Technologies Documentation Manager

Oracle Corporation

500 Oracle Parkway

Redwood City, CA 94065

FAX: 650-506-7228

You can also e-mail your comments to the Information Development department at the following e-mail address: infodev@us.oracle.com