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 









Clusters vs. Grids

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%.

There are many differences between Grid and Clusters. The following table shows comparison of Grid and Clusters.





Commodity Computers

Commodity and High-end computers





Membership Services

Centralized Index  and Decentralized Info

User Management



Resource management



Allocation/ Scheduling




VIA and Proprietary

No standards being developed

Single System Image








Varies, but high




Speed(Lat. Bandwidth)

Low, high

High, Low

Table 2.2: Comparison between Clusters and Grid

Grid represents a bigger framework and architecture, and focuses on the broader scope or objective. Grid incorporates many varied computing resources and the clusters often become one of the many components. A Grid enables the sharing, selection, and aggregation of a wide variety of geographically distributed resources including supercomputers, storage systems, data sources, and specialized devices owned by different organizations for solving large-scale resource intensive problems in science, engineering, and commerce. Clusters, on the other hand, focus on a specific objective and purpose, such as a database service or a web logic application server. These clusters fit into grid architecture very well for ultimate sharing of resources at a higher level of aggregation.

With technological advances it may not be long before a large number of nodes (say, 50 to 100 nodes) form a database cluster incorporating a variety of data stores consolidated into a huge data source. That may lead to a true Data Grid of different stores supported in a single large cluster.

Cluster Objectives

Traditionally, the term cluster was used to represent Server Clusters. Clustered systems are synonymous with a group of servers. The server, being the main layer or platform where the database or application service resides, is the most important component in providing availability and high performance.

 Clusters, with multiple nodes, primarily aim at protecting server availability. Any failure in a server is transparent to end-users and is hidden by the failover of the application or database to a surviving node. End users or clients have access to the surviving node, thus allowing processing to continue. In another situation, a group of nodes are joined together to provide database services, as in a parallel database. Failure of a single node does not interrupt access to the database since the secondary nodes are still active in providing database access.

Thus, the cluster technology focuses on providing an alternative to a failed server. However, we have to realize that there are many other layers or components, each of which is significant in maintaining overall availability of the database or application service. Although the server (node) is a very crucial component and plays the key role in running the database or application, there are other components, such as the disk storage units and networking equipment for which alternatives or backups need to be provided to meet the failure conditions. The traditional concept of clustering revolves around server clustering only.

With this in mind, administrators and managers should provide adequate redundancy for other components in order to have an effective high availability environment.


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