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 








  Oracle Database Tips by Donald Burleson

IBM Shared-Nothing Configuration

IBM has traditionally used the shared nothing disk architecture for all versions of its DB2 shared database except OS/390 (see Figure 14.6).      

The shared nothing configuration utilizes isolated disk assets for each server and the database (in the IBM implementation) is hashed across all of the servers. The database image is perceived by the users to be a single database and each machine has access to its own data. However, this implementation of the parallel database server falls prey to what is known as the "convoy effect". In a convoy of trucks or ships the speed of the convoy is limited by the speed of the convoys slowest member. It is the same with a database that is spread across isolated disk assets by hashing, the speed of database processing is limited by the speed of the slowest member of the cluster.

Another problem with the hashed spread of a database across multiple isolated disk assets is that the loss of one of the servers means loss of the entire database until the server or its disk assets are rebuilt and/or reassigned.      

In addition, due to the way the data is hashed across the servers and disks standard methods for maintaining data integrity won't work. This indicates that for a hashed storage database cluster much, if not all of the data integrity constraints must be programmed into the applications using complex two-phase commit algorithms instead of relying on built in constraint mechanisms.      

The final problem with the shared nothing approach used by IBM is that to add a new cluster member the data must be re-hashed across all members requiring database down time.

See Code Depot

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 -  2020

All rights reserved by Burleson

Oracle ® is the registered trademark of Oracle Corporation.