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

Time for action – switchover with a logical standby database using SQL*Plus


Now we will see a step-by-step approach to perform a switchover between the primary and the logical standby database:

  1. Check the switchover status of the primary database. Ensure that the status is either TO STANDBY or SESSIONS ACTIVE; if so, you are safe to perform a switchover as shown in the following code:

    SQL> select switchover_status from v$database;
    SWITCHOVER_STATUS
    --------------------
    TO STANDBY

    Note

    In case of RESOLVABLE GAP, wait until SQL was applied on the logical standby database; for other statuses, troubleshoot and fix the synchronization for the switchover process to be successful.

  2. Prepare the primary database for switchover. Execute the following command from the primary database so that the current primary database will be accepted to perform a switchover to a logical standby database:

    SQL> alter database prepare to switchover to logical standby;
    Database altered.

    On the primary alert log, issue...