How is Oracle Grid different from RAC?
Oracle RAC is an instance of a single database and application running across multiple clustered processors. A group of computers in a cluster are organized to perform the same function. According to the executive summary of the IOUG survey, clusters are generally perceived as a strategy for failover — if one of the nodes goes down, the application can keep running on another processor. For RAC, clustered processors must be identical. Grid architecture, in contrast, does not have this requirement. A grid is a collection of resources and may consist of multiple clusters. Grid systems are mainly perceived as a strategy for workload balancing, enabling the activation of new nodes as demand for computing power increases, according to the summary report. Some survey respondents indicated confusion about the difference between RAC and grid. “Some people use [the terms] synonymously,” Kaplan said. “People are very familiar with Oracle RAC because it’s been out so long — it’s an actual produ
