Database Reference
In-Depth Information
Channel Configuration
When you initiate an RMAN backup, RMAN will create one or more channels that connect
the database to a backup device. By default, RMAN will create a single channel to back up
or recover to or from the FRA. You can override the defaults using the CONFIGURE command.
Along with backup locations, the CONFIGURE command allows you to define other settings
for your backup channels, including parallelism and backup-set and piece-set sizing. In the
following sections, you'll learn about using the CONFIGURE command to define default backup
locations, about configuring parallelism, and then about using the CONFIGURE command to set
other channel-related parameters.
Configuring Backup Locations
The CONFIGURE DEFAULT DEVICE command is used to configure a backup location other than
the default location. If, for example, you wanted to back up to a directory called /oracle01/
backup/orcl , you would issue the following command:
RMAN> configure channel device type disk format '/oracle01/backup/orcl/%U';
RMAN will use this path for future backups. You can configure multiple channels with
the CONFIGURE command by specifying each individual channel, as shown here where we
have indicated different default backup locations for each channel:
RMAN> configure channel 1 device type disk format '/oracle01/backup/orcl/%U';
RMAN> configure channel 2 device type disk format '/oracle02/backup/orcl/%U';
You might have wondered about the %U in the backup location format. The %U is an
RMAN backup format specification. . There are a number of different format specifications.
%U is the most common because it ensures a unique filename for each backup set piece created
by RMAN. TableĀ 3.2 provides a list of the most common format specifications.
TABleĀ 3.2 Format Options
Option
Description
%a
Specifies the activation ID of the database
%c
Specifies the copy number of the backup piece within a set of duplexed
backup pieces
%d
Specifies the name of the database
%D
Specifies the current day of the month from the Gregorian calendar
%e
Specifies the archived log sequence number
%f
Specifies the absolute file number
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