Oracle Tips by Burleson

Oracle Dataguard
Chapter 9 - Recovery Manager and Data Guard

Explanation of RMAN Terminology

This section presents definitions of the RMAN terms used in the subsequent sections of this chapter:

• TARGET DATABASE – A Target Database is the primary database that will be backed up for RAC Grid creation. In RMAN’s terminology, the term target database identifies the database that is undergoing a backup, restore or recovery operation by Recovery Manager.
   

• AUXILIARY DATABASE – An Auxiliary Database is a RAC Grid that will be created as a result of the duplication of the target database. In RMAN’s terminology, Auxiliary instance identifies an instance which RMAN connects in order to execute the duplicate command.
   

• CHANNEL – A Channel is a communication pipeline between a RMAN executable and a target or auxiliary database. A channel consists of a server session on the target or auxiliary database and a data stream from the database to             the backup device or vice-versa. RMAN console sends commands to the database using this channel, and the server session running on the database executes the command on behalf of Recovery Manager. Some degree of parallelism during the backup or restore operation can be achieved using multiple channels.
   

• AUTOMATIC CHANNEL ALLOCATION – RMAN Channels can be configured to use a set of default attributes for each operation when a channel is not allocated manually. This set of channels is persistent and can be configured using the CONFIGURE command. When such a set of channels is pre-defined, it is called automatic channel allocation. By default, RMAN configures a channel of device type, DISK, to be used for automatic channel allocation.
   

• MANUAL CHANNEL ALLOCATION - As the name suggests, a channel can be configured manually for special needs such as increasing the degree of parallelism. Channels can be allocated manually by using the ALLOCATE CHANNEL command in the RUN block of RMAN statement.

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