Log Buffer Space

What is Oracle Real Application Clusters 10g?

Oracle Real Application Clusters is an option to Oracle database which was introduced with Oracle Real Application Clusters is now proven technology 9i.Oracle used by thousands of customers in every industry in every type of application. Oracle RAC provides the option to extend applications beyond the capabilities of a single server. This allows customers to take advantage of material cost of raw materials to reduce their total cost of ownership and provide a scalable computing environment that supports workload demand. Oracle RAC provides the ability to remove the server as a single point of failure in an application environment database.

Real Application Clusters Architecture

A RAC database is a database cluster. A cluster is a group of independent servers that cooperate as a single system. Clusters provide improved fault resilience and growth of modular single additional symmetric multiprocessing (SMP). In the case of system failure, clustering ensures high availability for users. Access to data for mission critical is not lost.
redundant hardware components, such as additional nodes, interconnects, and disks in the cluster can provide high availability. Such redundant hardware architectures avoid single points of failure and provide exceptional fault resilience.

With Real Application Clusters, we separate the Oracle instance (the processes and structures of memory running on a server to allow access to the data) from the Oracle database (the physical structures residing on the storage that actually hold the data, known as data files).
A database cluster is a single database which can be accessed by multiple instances. Each instance runs on a separate server in the cluster. When resources are needed, additional nodes and instances can be easily added to the cluster without interruption. Once the new instance is launched, the application services for help can take immediate advantage of it without any modification of the application or application server.

Oracle Clusterware

Oracle provides Oracle Clusterware, a portable solution that is integrated clusters specifically designed for Oracle Database. You no longer need to purchase third cluster to have a RAC database. Oracle Clusterware monitors and manages databases Real Application Cluster. When a cluster node is started, all instances, listeners and services are started automatically. If an instance does Clusterware automatically restart the instance so that the service is often restored before administering the opinion that it was declining.

Hardware Architecture

Oracle Real Application Clusters is a shared everything architecture. All servers in the cluster must share all storage used for a RAC database. The type of disk storage can be used for networked storage (NAS), storage area network (SAN), or a SCSI disk. Your choice of storage is dictated by the choice of server hardware and what your hardware vendor for support. The choice of a storage system that enables Scalable I / O request, an I / O system that will scale as additional servers are added to the cluster.

A cluster requires an additional network for the local network (LAN) server database is attached to the demand for connections. A cluster requires a second server is attached to the demand for connections. A group needs a second private network known as interconnection. Oracle recommends using two network interfaces for this network for high availability. A collage external network interface to Oracle should be used to provide failover and load balancing. The interconnection is used by cluster for messaging between nodes. Interconnection is also used by R.