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RMAN channel

An RMAN channel is needed in order to perform RMAN operations on a media manager (see media management software) The channel handles communication between RMAN and the (third party) media manager. Such a channel is allocated with the RMAN command allocate.

A channel is not needed if RMAN operates on a disk.

Channel types

RMAN supports the two channel types

SBT
disk (image copies)

RMAN commands

configure channel device type disk maxpiecesize 2G;
configure channel device type disk format /tmp/%u;
allocate channel chnl_1 device type disk;

Format specifiers (

The format specifiers determine the name of a backup piece.

configure channel device type disk format '/u01/backup_df%t_s%s_s%p';

The format specifiers are introduced with a percent sign:

%d the name of the database
%t backup time stamp (four characters?)
%s backup set number
%p backup piece number
%U can be used for most purposes in which case RMAN creates a unique file name

ASM disk location

configure channel device type disk format '+dgroup1';

Parallel operations

Ideally, there is one channel for each tape drive or physical disk.