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 – failover with a physical standby database using SQL*Plus


Follow these steps to complete a failover on the physical standby Data Guard environment:

  1. If you're able to mount a primary database, perform the following command to flush the redo from the primary online redo logfiles:

    SQL> alter system flush redo to INDIA_UN;

    Use DB_UNIQUE_NAME of the standby database so that redo will be sent to the respective standby database.

  2. Check the status of both the primary and standby databases. With the primary database in the MOUNT state, check the maximum archive log sequence that has been generated as shown in the following code:

    SQL> select max(sequence#) from v$archived_log;
    MAX(SEQUENCE#)
    --------------
               462
  3. If the primary database is inaccessible, refer to the alert logfile for the latest log switch sequence or go to the archive log location and check the maximum sequence number as shown in the following command:

    Fri Oct 12 22:20:30 2012
    Thread 1 advanced to log sequence...