 - Real Application Cluster (RAC) is a component of the Oracle 9i database product that allows a database to be installed across multiple servers. According to Oracle, RAC's shared disk method of clustering databases: increases scalability because servers can easily be added or subtracted to meet current needs, lowers costs because companies don't have to buy high-end servers, and improves availability because if one server fails, another can assume its workload.
RAC's shared disk architecture is an unusual approach to database clustering. Most competing database products (such as Microsoft's SQL Server and IBM's DB2 for Windows and Unix environments) use the alternative, which is known as "shared nothing" architecture. Shared nothing architecture partitions data and only gives each server access to its own disk subsystem, while shared
disk architecture gives all servers access to the entire database. This adds failover capacity to the database, because all servers have access to the whole database. Proponents claim that this capacity increases 9i's reliability and availability significantly. British Telecom, for example, reported that deploying the product enabled them to cut their failover time from a typical 20 minutes to between 10-60 seconds.
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Getting started with Real Application Cluster |
| To explore how Real Application Cluster is used in the enterprise, here are some additional resources: |
| Oracle RAC performance tuning: Check out an excerpt from the bestselling book "Oracle 10g Grid & Real Application Clusters" to learn how tuning an RAC database differs from tuning a non-RAC database. |
| Defining Real Application Clusters (RAC) vs. Storage Area Network (SAN): Confused about the definition of RAC? Read Oracle expert Brian Peasland's definition to learn how an RAC differs from an SAN (Storage Area Network). |
| Spotlight on RAC, grid and availability: In this special report, you'll find a compilation of advice, tips and analysis on the RAC feature. Learn how RAC works in a grid environment and how it can be used to improve availability. |
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Learn more about Oracle RAC and database clustering |
| Spotlight on RAC, grid and availability: This special report includes news, analysis and tips on grid computing and RAC to get you up to speed on these technologies and how they can help you improve availability. |
| Grid or RAC?: Which is better, RAC or 10g Grid? When to use both or either of these? What are the steps to install 10g Grid? Does it require a special license? |
| Oracle RAC design: The effects of component failure: The proper design of a Real Application Clusters (RAC) system is critical for all Oracle professionals. This book excerpt provides a quick look at the effects of component failure. |
| Performance tuning a RAC implementation: The performance tuning methodology for an Oracle Real Application Clusters (RAC) configuration can be broadly categorized into these seven steps. |
| Steps to implement RAC: I am an Oracle9i OCP. How can I implement a RAC application in Oracle Database in my system? Please give me the total steps to implement RAC. |
| Running RAC: Real Application Clusters (RAC) offer scalability and availability, but the cost and complexity may deter some users from running it. Read more about RAC inside. |
| DBA 102: Beyond the basics: Learn how to go beyond the basic roles of a DBA -- these hard and soft skills will help you prove your value to management and ensure your job security. |
| Mike Ault's Oracle "good practices": Backup, failover and disaster recovery: Mike Ault provides "good practices" for your Oracle backup, failover and disaster recovery strategy, including using a hot site, RMAN and mirroring. |
| Mike Ault's Oracle "good practices": Oracle environment: Mike Ault provides "good practices" for working in an Oracle environment, such as using Optimal Flexible Architecture (OFA) standards and verifying proper OS set points. |
| High-availability architecture and clusters: Data and application availability can make or break a business. This excerpt goes over some high availability terms for potential users of Oracle RAC. |
| LAST UPDATED: |
08 Aug 2008
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