Book Image

Oracle Data Guard 11gR2 Administration : Beginner's Guide

Book Image

Oracle Data Guard 11gR2 Administration : Beginner's Guide

Overview of this book

Data Guard is the high availability, disaster recovery and data replication solution for Oracle Databases. With the huge growth of Data Guard it's getting harder to encounter an Oracle DBA not dealing with Data Guard. Since it's a common DBA task to provide high availability of databases, Data Guard is a must-know topic for every Oracle Database Administrator."Oracle Data Guard 11g R2 Beginner's Administration Guide" is a practical guide that provides all the information you will need to configure and maintain Data Guard. This book will show you what Data Guard can really do.By following the practical examples in this book, you'll learn to set up your Data Guard Broker, the management framework for Data Guard configurations. Learn and implement different data protection modes, perform role transitions between databases (switchover and failover) and configure Active Data Guard. Next, we will dive into the features of Snapshot Standby. The book progresses into looking at Data Guard configuration with other Oracle products (such as EM, RAC, and RMAN) and patch databases in Data Guard. The final chapters will cover commonly encountered Data Guard issues and Data Guard best practices, which are very important to make a Data Guard configuration perfect and take maximum advantage of Data Guard properties.
Table of Contents (19 chapters)
Oracle Data Guard 11gR2 Administration Beginner's Guide
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Pop Quiz Answers
Index

Logical standby database characteristics


It's important to know the logical standby database properties well in order to decide if your business needs the physical or logical option. The different log apply modes make them distinct solutions for data replication, high availability, and disaster recovery. By using SQL Apply (the log apply method of logical standby databases), Data Guard mines the redo data (which was transferred from the primary database), builds the SQL statements (which will result in the same data change as in the primary database).

Finally executes these SQL statements on the logical standby database as shown in the following diagram:

Maintaining this kind of standby database has its own pros and cons. Now let's see what they are.

Not everything must be duplicated

Depending on your conditions, there may be cases where you don't want all the data in your primary database to be replicated. This is not possible with a physical standby database; however, the logical standby...