Oracle-related memory and background processes that run on a computer system. In an Oracle RAC environment, 2 or more instances concurrently access a single database. This allows an application or user to connect to either computer and have access to a oracle data guard pdf coordinated set of data. The instances are connected within each other through an “Interconnect” which enables all the instances to be in sync in accessing the data.
Oracle 9i addressed this issue: RAC uses a dedicated network connection for communications internal to the cluster. RAC access the same database, the overall system must guarantee the coordination of data changes on different computers such that whenever a computer queries data, it receives the current version — even if another computer recently modified that data. Oracle Real Application Clusters 12c Release 1 Enterprise Edition. RAC to single-node installations running Oracle Database 11g Release 2 Enterprise Edition. Relative to the single-instance Oracle database, Oracle RAC adds additional complexity. Oracle 10g, Oracle’s clusterware product was available for all operating systems.
Cluster Ready Services was renamed to Oracle Clusterware. You can still use clusterware from other vendors, if the clusterware is certified for Oracle RAC. RAC, as no need for ownership-transfer exists. Oracle 11g has made many enhancements in this area and performs a lot better than earlier versions for read-only workloads.
This makes Oracle RAC horizontally scalable with many nodes. Oracle RAC to demonstrate the scalability of their application. Oracle RAC 11g supports up to 100 nodes. However, if the application cannot scale linearly on SMP, it will not scale when ported to RAC. Oracle Corporation offered a Shared Nothing architecture RDBMS with the advent of the IBM SP and SP2 with the release of 7. Shared Everything implementation on a Shared Nothing architecture. Shared-everything” architectures share both data on disk and data in memory between nodes in the cluster.
This is in contrast to “shared-nothing” architectures that share none of them. Some commercially available databases offer a “shared-everything” architecture. 1990s when IBM released its mainframe hardware and software-clustering infrastructure. DB2 data sharing on the mainframe. It resembles Oracle RAC in its shared-everything design.