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

Cascade standby databases


The cascade standby database concept was introduced from Oracle 9i Release 2 onwards. In the latest versions and releases there are many changes in the cascade standby databases. The cascade standby database concept was introduced to reduce the load on your primary database and to transmit redo data from the primary to all standby databases, and the network bandwidth needs to be large enough to handle the load. If it is a huge OLTP then it will be more problematic to handle. The cascade standby databases are shown in the following diagram:

Limitations with cascade standby database

The limitations with a cascade standby database are as follows:

  • Data cannot be transmitted to other standby databases from a logical standby or a snapshot standby database.

  • Data Guard broker is not supported in a cascade standby database environment.

  • Cascading is not supported in RAC on versions prior to 11.2.0.2.

  • If you are using synchronous redo transport, they cannot cascade redo data in...