Book Image

Oracle 11g R1/R2 Real Application Clusters Essentials

Book Image

Oracle 11g R1/R2 Real Application Clusters Essentials

Overview of this book

Oracle RAC or Real Application Clusters is a grid computing solution that allows multiple nodes (servers) in a clustered system to mount and open a single database that resides on shared disk storage. Should a single system (node) fail, the database service will still be available on the remaining nodes. Oracle RAC is an integral part of the Oracle database setup. You have one database with multiple users accessing it, in real time. This book will enable DBAs to get their finger on the pulse of the Oracle 11g RAC environment quickly and easily.This book will cover all areas of the Oracle RAC environment and is indispensable if you are an Oracle DBA who is charged with configuring and implementing Oracle11g R1, with bonus R2 information included. This book presents a complete method for the configuration, installation, and design of Oracle 11g RAC, ultimately enabling rapid administration of Oracle 11g RAC environments.This practical handbook documents how to administer a complex Oracle 11g RAC environment. Packed with real world examples, expert tips and troubleshooting advice, the book begins by introducing the concept of Oracle RAC and High Availability. It then dives deep into the world of RAC configuration, installation and design, enabling you to support complex RAC environments for real world deployments. Chapters cover Oracle RAC and High Availability, Oracle 11g RAC Architecture, Oracle 11g RAC Installation, Automatic Storage Management, Troubleshooting, Workload Management and much more. By following the practical examples in this book, you will learn every concept of the RAC environment and how to successfully support complex Oracle 11g R1 and R2 RAC environments for various deployments within real world situations. This book is the updated release of our previous Oracle 11g R1/R2 Real Application Clusters Handbook. If you already own a copy of that Handbook, there is no need to upgrade to this book.
Table of Contents (20 chapters)
Oracle 11g R1/R2 Real Application Clusters Essentials
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

ASM backup strategies


You may have been surprised when you first heard of backup strategies for ASM because ASM doesn't have any physical structure (no physical datafiles); it is just a special kind of instance, and there is actually no need to back it up. Having said so, it is strongly advised to back up all the important information in case of a disaster.

Pre-Oracle ASM 11g, there was no direct option to back up the ASM configuration and its metadata information. However, the recommended option in pre-11g was to gather the important information by spooling it in a text or HTML file through querying the ASM specific dynamic views, such as V$ASM_DISK, V$ASM_FILES, V$ASM_DISKGROUP, V$ASM_CLIENT, and so on.

md_backup and md_restore commands

With 11g R2, Oracle provides two new commands: md_backup and md_restore, which can be used within the ASMCMD utility to backup and restore the disk group metadata.

The purpose of the md_backup command is to back up the metadata for one or more disk groups,...