René Nyffenegger's collection of things on the web
René Nyffenegger on Oracle - Most wanted - Feedback -
 

Oracle High Availability Architectures

database only

A single instance runs on one standalone machine.
With flashback technology, it is possible to quickly undo user errors such as accidentally dropping a table.
Downtime is minimized as tables and indexes can be reorganized online.
RMAN automates backup and recovery which is configured to the needs of the business.

RAC only

A set of nodes form a real application cluster. If an instance fails, an other instance will provide the service of the failed instance.
rolling patch upgrade

Data guard only

The productive site runs on the primary database. One or more secondary sites have a logical or a a physical standby database.
When there is a failure at the productive site, the DBA can use Data Guard to fail over to a secondary site. However, this failover must be triggered manually.
disaster recovery

Maximum Availability Architecture (MAA)

The primary site has a RAC environment. The secondary site(s) have clusters with both physical and logical standby databases.
This is the most secure architecture against inavailability.

Streams

Transactions on the primary site are replicated to a secondary site using streams.
The platforms can be different on the primary site and on the secondary site.
replication