Oracle provides four popular high availability solutions:
- Oracle Advanced Replication
- Oracle Real Application Clusters (RAC)
- Oracle Data Guard (physical/logical standby database)
- Oracle Streams
Advanced Replication
Replication is the process of copying and maintaining database objects, such as tables, in multiple database that make up a distributed database system. Changes applied at one site are captured and stored locally before being forwarded and applied at each of the remote locations.
Replication supports a variety of applications that often have different requirements. Some applications allow for relatively autonomous individual materialized view sites. Other applications require data on multiple servers to be synchronized in a continuous, nearly instantaneous manner to ensure that the service provided is available and equivalent at all times.
Real Application Clusters (RAC)
Oracle Real Application Clusters (RAC) allows multiple instances accessing a single database. The typical installation involves a cluster of nodes with access to a set of shared disks.
Data Guard
Oracle Data Guard is the management, monitoring, and automation software that work with a production database and one or more standby databases to protect data against failures, errors, and corruption that might otherwise destroy your database.
Streams
Oracle Streams enables you to share data and events in a stream. The stream can propagate this information within a database or from one database to another. The stream routes specified information to specified destinations.
Using Oracle Streams, you control what information is put into a stream, how the stream flows or is routed from database to database, what happens to events in the stream as they flow into each database, and how the stream terminates.
