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 – testing real-time apply


If real-time apply is enabled, the apply services can apply redo data without waiting for the current standby redo logfile to be archived. This allows faster role transitions because you avoid waiting for a redo log to be transported to the standby database and then applied. In this example, we'll see how changes are transferred and applied to the standby database. The redo log that includes changes is not archived on primary.

  1. In order to use real-time apply, the redo transport service from primary to standby must use LGWR. Run the following query on the primary database and check the log archive destination configuration.

    SQL> show parameter log_archive_dest_2
    NAME                TYPE       VALUE
    ------------------- --------   ----------
    log_archive_dest_2  string     SERVICE=INDIA LGWR ASYNC VALID_FOR                                                                                       =(ONLINE_LOGFILES,PRIMARY_ROLE)                    DB_UNIQUE_NAME...