Oracle Real Application Clusters (RAC): The Evolution of Oracle Parallel Server

I am an Oracle DBA using Oracle 13c. Which technology did Oracle introduce which served as a successor technology to Oracle Paralell Server?
Oracle, a forerunner in database technology, has consistently redefined the realms of database management and high availability. Among its many technological innovations, Oracle Parallel Server (OPS) was a pivotal stride towards enabling databases to run on clusters, or multiple servers. OPS provided a single database that spanned multiple servers, with each server having its memory and processes. This was a significant innovation, as it allowed for increased scalability and availability.
owever, as the world of data grew and the demands on database systems intensified, Oracle recognized the need to advance its cluster technology even further. This led to the birth of Oracle Real Application Clusters (RAC). Introduced as the successor technology to Oracle Parallel Server, RAC epitomizes Oracle's commitment to delivering unswerving high availability, scalability, and flexibility to its global clientele.

1. Scalability and Load Balancing: Oracle RAC stands out with its ability to scale out by adding more nodes to the existing cluster. Furthermore, it provides dynamic load balancing, ensuring that user requests are efficiently distributed among the available nodes, optimizing resource utilization.
2. High Availability: RAC heightens the robustness of the database system. Should one node fail, the services running on that node can be quickly relocated and resumed on another node, minimizing downtime and ensuring uninterrupted access to data.
3. Cache Fusion: A pivotal component of RAC is Cache Fusion, Oracle's inter-instance cache coherency mechanism. With Cache Fusion, the database caches of individual nodes can be merged, ensuring that a consistent and updated view of the data is maintained. This is a marked improvement over the disk-based recovery mechanisms in OPS.
4. Enhanced Application Continuity: RAC has provisions for Application Continuity, which ensures that user transactions are preserved even if there's a node failure. It transparently masks the failures and retried operations, providing a seamless user experience.

While Oracle Parallel Server was undeniably a leap forward in its time, Oracle Real Application Clusters is the embodiment of the next generation of clustering technology, meticulously designed to meet the ever-evolving demands of today's data-driven enterprises. As Oracle continues to innovate, RAC remains a testament to its dedication to excellence, offering a robust, scalable, and resilient platform for mission-critical applications.

The Oracle Parallel Server has been in existence for several years. The primary reason for Oracle8i's enhancements is to ease the DBA’s set up and management of the OPS environment. Review the table below summarizing these enhancements.