The main purpose of Oracle Real Application Clusters (RAC) is to maximize availability and enable horizontal scalability of an Oracle database by allowing it to run across multiple servers while accessing shared storage. This provides redundancy and increased processing power.
Understanding Oracle RAC
Oracle RAC achieves its purpose through several key features:
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High Availability: If one server in the cluster fails, the database continues to run on the remaining servers, minimizing downtime. This is crucial for applications that require continuous operation.
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Scalability: As demand grows, you can add more servers to the RAC cluster to increase processing capacity without requiring major application changes. This horizontal scalability is a significant advantage.
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Shared Storage: All servers in the cluster access the same database files stored on shared storage. This ensures data consistency and allows any server to handle requests.
How RAC Works: A Simplified View
Think of RAC as a team of servers working together on the same database. Each server has its own processing power and memory, but they all share access to the same data files. When a user or application makes a request, it can be handled by any available server in the cluster.
Here's a table summarizing the key aspects:
| Feature | Description | Benefit |
|---|---|---|
| Multiple Servers | Database runs across several servers. | High availability and increased processing power. |
| Shared Storage | All servers access the same database files. | Data consistency and flexible request handling. |
| Scalability | Add more servers to the cluster as needed. | Accommodate growing demand without major application changes. |
Example Use Case
Imagine an e-commerce website that experiences high traffic during peak hours. Using RAC, the website can distribute the load across multiple servers, ensuring that the site remains responsive and available even during periods of heavy demand. If one server fails, the other servers seamlessly take over, preventing any disruption to service.
In Conclusion
Oracle RAC is designed to ensure that your Oracle database is always available and can handle increasing workloads, providing a robust and scalable solution for critical applications, which allows customers to run a single Oracle Database across multiple servers in order to maximize availability and enable horizontal scalability, while accessing shared storage.
