Real Application Clusters

Oracle Real Application Clusters (RAC) is the world’s only scale-everything, highly available database architecture. It transparently scales both reads and writes for all workloads, including OLTP, analytics, AI vectors, SaaS, JSON, batch, text, graph, the Internet of Things (IoT), and in-memory. Oracle RAC effortlessly scales complex applications, such as SAP, Oracle Fusion Applications, and Salesforce workloads. It provides best-in-class high availability through most hardware and software failures and maintenance events. This is why leading banks, stock exchanges, telecoms, retailers, governments, and utilities use Oracle RAC for their critical, 24/7 workloads—on-premises and in the cloud.

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Why Oracle RAC's unique capabilities excel

    • Oracle RAC transparently delivers the lowest latency and highest throughput for all data needs. Its unique, fused cache across servers helps ensure ultrafast local data access, while parallelized workloads across all CPUs guarantee maximum throughput. The integration of Oracle’s Stripe and Mirror Everything storage design completes this scale-everything architecture by enabling seamless online storage expansion.

    • Unlike other databases that depend on public cloud infrastructures, sharding, or read replicas for scalability, Oracle RAC guarantees the lowest latency and highest throughput out of the box.

    • Oracle RAC dramatically accelerates long-running workloads, such as analytics, batch, indexing, data reorganization, and application schema changes by transparently distributing and parallelizing queries, updates, inserts, and deletes across multiple servers, including data definition language. This enables SQL requests to leverage all the cluster's CPU, memory, and I/O resources.

    • Parallel operations, not just queries, run much faster on Oracle RAC than on databases that only offer queries to run in parallel, restrict write operations to one server, or attempt to break the function down by keys, which can overwhelm the network, as data may need to be copied across all servers in the cluster.

    • Oracle RAC provides faster SQL response times for OLTP workloads than other scale-out databases. Its unique Cache Fusion technology allows local data access and caching, reducing costly cross-server messaging. When deployed on Oracle Exadata, the unique use of RDMA across Exadata servers further accelerates OLTP workloads.

    • Other scale-out databases rely on read replicas for scaling reads but run all writes on a primary server, limiting OLTP scaling and risking stale data, which may cause applications errors or wrong results. Alternatives using statically assigned data ranges require expensive remote messages to access nonlocal data.

    • Oracle Autonomous Database leverages Oracle RAC and Exadata, adding instant compute and storage scaling with a single click, while automatic scaling and indexing help ensure zero complexity scale-out. This delivers pay-per-use and makes all Oracle RAC benefits accessible for databases and workloads of any size, from the smallest databases and workloads to hundreds of thousands of tables and indexes and millions of SQL statements.

    • Unlike purpose-built or cloud-dependent open source databases using complex data models to scale, Oracle RAC is uniquely designed for unmatched OLTP, data warehousing, analytical, and AI workload performance at any scale.

    • Using built-in scalable application connection libraries, Oracle RAC protects applications from hardware and software failures by automatically and transparently failing over application connections from impacted servers to surviving servers in the cluster.

    • Where other databases require replication or complex data mirroring mechanisms (often only offered on specific cloud environments) to help ensure high availability, Oracle RAC transparently protects applications, including mission-critical applications, such as SAP, PeopleSoft, and Oracle Fusion Applications, on all supported platforms, across cloud, on-premises, and hybrid cloud.

    • Oracle RAC provides unique online software patching and update capabilities, enabling applications to run transparently without downtime or brownout while the underlying databases or servers are updated. This allows customers to swiftly and regularly update and protect their database systems against increasingly frequent and sophisticated security vulnerabilities.

    • Unlike other database solutions that abort running applications during updates and call this zero downtime patching, Oracle RAC easily migrates and does not abort or abruptly disconnect applications from an Oracle Database. This avoids connection storms and brownouts due to cold-starting database caches during the update process.

    • Oracle RAC helps ensure application continuity by transparently failing over or moving applications and connections between servers after a hardware or software failure or during server or database maintenance without needing application developers to consider and code against those incidents. This makes Oracle RAC the easiest-to-adopt database high availability solution for developers.

    • Unlike other databases, Oracle RAC provides Continuous Availability throughout the application development lifecycle. Utilizing its unique online update features, Oracle RAC seamlessly integrates into continuous integration and continuous delivery (CI/CD) workflows by allowing rolling database and application schema updates.

    • The unique integration with Oracle’s converged database and its efficient, yet flexible, resource separation capabilities based on Oracle's pluggable databases allow Oracle RAC to effectively consolidate and scale multiple workloads and use cases in the same database, avoiding complex integration or data migration services outside of the database when data needs to be shared across use cases.

    • Unlike purpose-built databases or schema-based consolidation, Oracle's pluggable databases support diverse workloads, including OLTP, data warehousing, NoSQL, Graph, Spatial, and Vector Search, in the same Oracle RAC-based container database, ensuring no workload impacts the performance of others, thereby avoiding the problem of "noisy neighbors."

New Generation Oracle RAC

Oracle Real Application Clusters 23ai includes many improvements that enable applications to achieve significantly better levels of availability and scalability than previous versions. These improvements create a new generation of Oracle RAC technology ready to meet the needs of next-generation workloads and applications, including AI workloads.

Customer successes

Oracle Real Application Clusters are used by customers around the world to increase Oracle Database availability and scale database performance across multiple database servers.

AmerisourceBergen logo
Banque Misr Liban S.A.L. (BML) logo
Kassenärztliche Bundesvereinigung (KBV) logo
Korea Deposit Insuance Corporation logo
NTT Docomo Systems, Inc. logo
Port of Fujairah logo
Qatalum logo
Union Life logo
Wargaming logo

Wargaming uses Oracle RAC to achieve zero downtime for their databases

Hear more about Oracle RAC from customers and experts

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Additional resources

Related products and technologies

Oracle RAC One Node

Enhance availability for single instance databases

Application Continuity

Provide continuous availability

Oracle Clusterware

Use clustered servers as a single system

Automatic Storage Management

Simplified storage management

Advanced Cluster File System

POSIX and X/OPEN compliant cluster file system supports multiple OS

Autonomous Health Framework

Maintain database availability and performance

Autonomous Database

The future of Oracle Database

Oracle Engineered Systems

The Best Platform for Oracle Database

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