Real Application Clusters with Oracle Database 11g, enables a single database to run across a cluster of servers, providing unbeatable fault tolerance, performance, and scalability with no application changes necessary. This white paper provides a technical overview of Oracle Real Application Clusters 11g Release 2 with an emphasis on the features and functionality that can be implemented to provide the highest availability and scalability for your enterprise applications.
An Oracle White Paper December 2009
Oracle Real Application Clusters One Node:
The Always Online Single-Instance Database
Oracle White Paper-Oracle Real Application Clusters One Node
Executive Summary........................................................................... 1
Oracle Real Application Clusters One Node ...................................... 1
Better Server Consolidation........................................................... 6
Enhanced Protection from Failures................................................ 4
Greater Flexibility and Workload Management .............................. 9
Better Online Maintenance ............................................................ 2
Other Unique Benefits of Oracle RAC One Node......................... 11
Complements Server Virtualization................................................ 9
Conclusion ...................................................................................... 12
Oracle White Paper-Oracle Real Application Clusters One Node
Executive Summary Oracle Real Application Clusters (RAC) One Node is a new option to Oracle Database 11g Release 2 Enterprise Edition. It provides enhanced high availability for single-instance databases, protecting from both planned and unplanned downtime. Oracle RAC One Node provides:
. Always on single-instance database services . Better consolidation for database servers . Enhanced server virtualization . Lower cost development and test platform for full RAC
In addition it allows customers to consolidate database storage, standardize their database environment, and, should the need arise, upgrade to a full multi-node Oracle RAC database without downtime or disruption.
Oracle Real Application Clusters One Node
With Oracle Database 11g Release 2, Oracle introduces Oracle Real Application Clusters (RAC) One Node, a new feature that provides always on availability for single-instance databases (i.e., databases that run on only one server at a time).
Availability is a growing concern for all customers. Information, and the databases underlying that information, have become more and more integral to business processes and products. Windows of downtime for planned maintenance no longer exist, as users all over the world are dependent on access to data. To continue to meet service levels with reduced staffing requires an infrastructure that automatically recovers from failures without administrator intervention, and allows administrators to perform maintenance without downtime.
Oracle RAC One Node leverages the capabilities of Oracle RAC to extend Oracle RAC's availability benefits to single-instance databases. Single-instance databases can now enjoy online maintenance, including online server and storage replacement, online operating system upgrades and patching, online database patching, and automatic recovery from software and hardware failures.
Oracle RAC One Node provides more than just always on availability. Its ability to online migrate instances from one server to another enable customers to better consolidate their databases, vastly improving on the rudimentary server consolidation offered by server virtualization. When used in conjunction with server virtualization products like Oracle VM,
1 Oracle White Paper-Oracle Real Application Clusters One Node
Oracle RAC One Node enhances the benefits of virtualization, leveraging the strengths of both products. The figure below represents a typical RAC One Node deployment.
In this example configuration, we have five single-instance Oracle RAC One Node databases running in a cluster of three servers. Server A is hosting Oracle RAC One Node databases DB1 and DB2, server B is hosting database DB3 and server C is hosting databases DB4 and DB5. Each server runs one OS. In servers A and C above, multiple databases are consolidated onto a single OS. This deployment itself provides many consolidation benefits. However, Omotion, a unique feature of Oracle RAC One Node that provides live migration of databases across nodes in the cluster, enables many additional benefits. Below is a depiction of Oracle RAC One Node Omotion feature:
2 Oracle White Paper-Oracle Real Application Clusters One Node
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