Databases Reference
In-Depth Information
Making Faster Backups of Large Files
Problem
You want to make faster backups of a large data file.
Solution
You can back up a large data file faster by dividing the backup work among multiple channels so they can back up the
large data file in parallel. To do this, you can make a
multisection backup
, wherein each channel backs up a section of
a data file, thus enhancing performance.
You perform a multisection backup by specifying the
section size
parameter in the
backup
command. Here are
the steps you must follow to make a multisection backup:
1.
Connect to the target database.
$ rman target sys/<sys_password>@target_db
2.
Configure channel parallelism. In this example, we use a parallel setting 3 for the sbt
device, as shown here:
run{
allocate channel c1 device type sbt
parms 'ENV=(OB_DEVICE=testtape1)';
allocate channel c2 device type sbt
parms 'ENV=(OB_DEVICE=testtape2)';
allocate channel c3 device type sbt
parms 'ENV=(OB_DEVICE=testtape3)';
Execute the backup, specifying the
section size
parameter:
3.
RMAN> backup
2> section size 150m
3> tablespace system;
Starting backup at 28-SEP-12
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
...
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
channel ORA_DISK_1: starting piece 1 at 28-SEP-12
channel ORA_DISK_1: finished piece 1 at 28-SEP-12
piece handle=/u01/app/oracle/fast_recovery_area/CATDB/backupset/2012_09_28/o1_mf_ncnnf_
TAG20120928T102135_86cj5x8x_.bkp tag=TAG20120928T102135 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 28-SEP-12
RMAN>
