What is the Difference Between ORACLE Dataguard and Real Application Cluster (RAC)?

Oracle Data Guard and Real Application Cluster (RAC) are two different concepts in Oracle database management, focusing on different aspects of high availability and disaster recovery. Here are the key differences between the two:

Database Instances: RAC has one database and several instances associated with it, while Data Guard has several databases, including one primary and multiple standby databases.
High Availability: RAC is primarily focused on providing high availability and scalability through a clustered database architecture. It uses multiple instances running on multiple servers (nodes) connecting to a single database, ensuring that the database remains accessible even if one of the nodes goes down.
Disaster Recovery: Data Guard, on the other hand, is focused on disaster recovery and offloading read-only workloads to standby databases. It provides a failover solution in case of site failures, such as fire, flood, or hardware failure, ensuring that the data remains accessible from a separate site.
Scalability: RAC is recommended for instance, software, and hardware failures, as well as for handling workload growth in a single database. Data Guard is more suitable for site failures and disaster recovery scenarios.

In summary, Oracle Real Application Cluster (RAC) is primarily concerned with high availability and scalability through a clustered database architecture, while Data Guard focuses on disaster recovery and offloading read-only workloads to standby databases.

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What is the Difference Between ORACLE Dataguard and Real Application Cluster (RAC)?

Comparative Table: ORACLE Dataguard vs Real Application Cluster (RAC)

Oracle Data Guard and Real Application Clusters (RAC) are two different high availability and disaster recovery solutions in Oracle databases. Here is a table comparing their key differences:

Feature	Oracle Data Guard	Oracle RAC
Purpose	Disaster recovery and offloading read-only workloads to standby databases	High availability and scalability through a clustered database architecture
Configuration	At least one standby database for the primary database	Single database utilizing resources of two or more servers
Readiness	Standby databases can be on the same site or a separate site (recommended) of the primary database	Multiple instances running on two or more servers (nodes) connecting to the same database
Failover	Primarily for site failures rather than instance, software, or hardware failures	Automatically directs users to a running node if one system goes down
Accessibility	Data Guard focuses on recovery by having several databases (one primary and others as standby databases)	RAC focuses on accessibility by having one database and several instances associated with it
Protection Mode	Maximum protection configuration: If all active destinations are lost, then all primary database instances lose connectivity and are shut down	Other instances in an Oracle RAC continue to process transactions on the remaining SYNC destination(s) if a lost destination is not the last participating SYNC destination

In summary, Oracle Data Guard is focused on disaster recovery and offloading read-only workloads to standby databases, while Oracle RAC is primarily focused on providing high availability and scalability through a clustered database architecture.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.