Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles
New Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 









Online and Real-Time Access to Corporate Data

Oracle RAC Cluster Tips by Burleson Consulting

This is an excerpt from the bestselling book Oracle Grid & Real Application Clusters.  To get immediate access to the code depot of working RAC scripts, buy it directly from the publisher and save more than 30%.

In order to achieve online and real-time access, the data must be available on high-speed access devices. High-speed access devices translate into multiple fast-access disk drives (10,000 to 15,000 RPM low latency disk drives), connected by high-speed bus technology to computers capable of handling complex operations.

Today's high-speed disks and computers more than match these requirements. With CPU speeds nearing 4 gigahertz and internal bus speeds of 400 megahertz, the limiting factor in many systems is the design of the database and its queries, not the underlying technology.

In order to provide online and real-time access to corporate data, companies must eliminate single points of failure in their computer architecture and in their computer support staffing. Companies should ask themselves if there is anyone in the support staff who is irreplaceable. If so, they need to begin training their replacement as soon as possible.

Oracle RAC technology provides a scalable answer to real-time and online access to data, by increasing the amount of resources, which can be applied to a problem, and eliminating single points of failure in corporate databases. This book will reveal how, with proper planning and resource utilization, there should never be a problem with online and real-time access to a database again.

Oracle?s Cluster Technology

Oracle has had the ability to run in parallel server mode since version 6.2. In Oracle parallel server mode, two or more Oracle instances share a single set of database files. An instance of Oracle is comprised of the executable image, background processes, control files, instance-specific initialization files, redo log threads, and a set of either shared or private rollback or undo segments. A shared database consists of the data files that make up all tablespaces in the database.

Until later versions of Oracle8i, a shared Oracle database system had to use a laborious process of copying blocks into and out of memory, and to and from disks, in order to share information in a single block between the multiple instances. This complex sharing mechanism resulted in performance issues if the database didn't utilize some kind of application partitioning, data partitioning, and localized use. Oracle 9i Real Application Clusters (RAC) relieved DBA(s) and designers from these limitations and problems. Now the 10g RAC extends the benefits of the RAC system and integrates well with enterprise grid enterprises. 10g RAC database focuses more on the service-oriented approach towards the client usage. Workload management has been streamlined for efficient use of the RAC database.

Using the Oracle Cache Fusion architecture, the RAC architecture provides two critical functions:

* True scalability

* Enhanced reliability

RAC allows the DBA true transparent scalability. In order to increase the number of servers in most architecture, including Oracle's previous OPS, data and application changes were required, in many cases, to prevent performance from actually deteriorating. With RAC, the following advantages exist:

* All Applications Scale ? No tuning is required

* No Physical Data Partitioning is required

* ISV Applications Scale out of the box

This automatic, transparent scaling is due almost entirely to RAC?s cache fusion and the unique parallel architecture of RAC implementation on Oracle9i. Since the processing of requests is spread across the RAC instances evenly, and all instances access a single database image instead of multiple images, the addition of a server or servers requires no architecture changes, no re-mapping of data, and no recoding. In addition, the failure of a single node results only in the loss of scalability.


This is an excerpt from the bestselling book Oracle Grid & Real Application Clusters, Rampant TechPress, by Mike Ault and Madhu Tumma.

You can buy it direct from the publisher for 30%-off and get instant access to the code depot of Oracle tuning scripts.


Oracle Training at Sea
oracle dba poster

Follow us on Twitter 
Oracle performance tuning software 
Oracle Linux poster


Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  

and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright © 1996 -  2017

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.

Remote Emergency Support provided by Conversational