Configuring and Allocating Channels for Use in Backups

You have the following options for executing backups:

• Configure automatic channels with the CONFIGURE command, and then issue BACKUP commands at the RMAN prompt or within a RUN block

• Within a RUN block, allocate channels manually with the ALLOCATE CHANNEL command, and then issue BACKUP commands using those channels

The easiest way to make backups is to configure automatic channels. For example, so long as you have already configured an sbt device type, you can configure a default sbt channel as follows (note that the PARMS value is vendor-specific) and then back up the database using these defaults:

RMAN> CONFIGURE DEVICE TYPE sbt PARALLELISM 1;
RMAN> CONFIGURE DEFAULT DEVICE TYPE TO sbt;
RMAN> CONFIGURE CHANNEL DEVICE TYPE sbt PARMS 'ENV=(NSR_SERVER=bksvr1)';
RMAN> BACKUP DATABASE;

RMAN preconfigures a DISK channel for you, so you can make disk backups using automatic channels without performing any configuration whatsoever.

The other method is to allocate channels manually within a RUN block before running the BACKUP command. For example, this command allocates multiple disk channels and then backs up the database and archived redo logs:

RMAN> RUN
{ 
  ALLOCATE CHANNEL ch1 DEVICE TYPE DISK;
  ALLOCATE CHANNEL ch2 DEVICE TYPE DISK;
  ALLOCATE CHANNEL ch3 DEVICE TYPE DISK;
  BACKUP DATABASE PLUS ARCHIVELOG;
}

The following example manually allocates an sbt channel (with a vendor-specific PARMS value) and backs up a datafile copy:

RMAN> RUN
{ 
  ALLOCATE CHANNEL ch1 DEVICE TYPE sbt PARMS 'ENV=(NSR_SERVER=bksvr1)';
  BACKUP DATAFILECOPY '/tmp/system01.dbf';
}

Most examples in this chapter assume that you have configured automatic channels.