Databases Reference
In-Depth Information
Not Using a FRA
You may have an environment where you have multiple backup locations on disk and you want to perform RMAN
operations in parallel. In this situation you can manually configure channels to write backups to separate locations.
For example, say you have two separate mount points where you want to write the backups. You can configure that
as follows:
RMAN> configure device type disk parallelism 2;
RMAN> configure channel 1 device type disk format '/u01/rman/o12c/rman1_%U.bk';
RMAN> configure channel 2 device type disk format '/u02/rman/o12c/rman2_%U.bk';
RMAN> backup database;
When the
backup
command is executed, RMAN will spread the backup pieces across the two configured
channels. If you set the degree of parallelism to 1, then RMAN will back up using only the first channel device defined
(even if you have configured two or more channels).
Keep in mind that the disk location specified in this example may not match your environment. You will have
to change the directory paths to match backup locations that exist on your sever. If the directories don't exist, you'll
receive this error:
ORA-19504: failed to create file...
ORA-27040: file create error, unable to create file
■
Note
the
%U
in the configuration statement instructs rMan to create unique backup piece names.
Another method for enabling parallelism is to format the
allocate channel
command. This command must
be run within a
run{}
block and there's no need to specify a degree of parallelism (it's derived from the number of
allocated channels):
RMAN> run{
allocate channel d1 device type disk format '/u01/rman/o12c/rman1_%U.bk';
allocate channel d2 device type disk format '/u02/rman/o12c/rman2_%U.bk';
backup database;
}
Another technique for enabling parallelism is to format the
backup
command with multiple locations. Here you
do have to specify the degree of parallelism:
RMAN> configure device type disk parallelism 2;
RMAN> backup database format '/u01/rman/o12c/rman1_%U.bk',
'/u02/rman/o12c/rman1_%U.bk';
It's mostly a personal preference as to which technique you use to enable parallelism.
■
if you enable parallelism, are not using a Fra, and don't configure explicitly the location of the backup pieces,
then rMan will write in parallel backup pieces to the default location (usually OraCLe_hOMe/dbs).
Note
