Database Reference
In-Depth Information
Starting with Oracle 11g, you can instruct RMAN to use multiple channels to back up one data file in parallel.
This is known as a multisection backup. This feature can speed up the backups of very large data files. Use the
SECTION SIZE
parameter to make a multisection backup. The following example configures two parallel channels to
back up one file:
RMAN> configure device type disk parallelism 2;
RMAN> configure channel 1 device type disk format '/u01/O12C/rman/r1%U.bk';
RMAN> configure channel 2 device type disk format '/u02/O12C/rman/r2%U.bk';
RMAN> backup section size 2500M datafile 10;
When this code runs, RMAN will allocate two channels to back up the specified data file in parallel.
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Note
if you specify a section size greater than the size of the data file, rMaN will not back up the file in parallel.
Adding RMAN Backup Information to the Repository
Suppose you've had to re-create your control file. The process of re-creating the control file wipes out any information
regarding RMAN backups. However, you want to make the newly created control file aware of RMAN backups sitting
on disk. In this situation, use the
CATALOG
command to populate the control file with RMAN metadata. For example,
if all the RMAN backup files are kept in the
/u01/O12C/rman
directory, you can make the control file aware of these
backups files in the directory, as follows:
RMAN> catalog start with '/u01/O12C/rman';
This instructs RMAN to look for any backup pieces, image copies, control file copies, and archive redo logs in
the specified directory, and, if found, to populate the control file with the appropriate metadata. For this example two
backup piece files are found in the given directory:
searching for all files that match the pattern /u01/O12C/rman
List of Files Unknown to the Database
=====================================
File Name: /u01/O12C/rman/r1otlns90o_1_1.bk
File Name: /u01/ O12C/rman/r1xyklnrveg_1_1.bk
Do you really want to catalog the above files (enter YES or NO)?
If you enter
YES
, then metadata regarding the backup files will be added to the control file. In this way, the
CATALOG
command allows you to make the RMAN repository (control file and recovery catalog) aware of files that
RMAN can work with for B&R.
You can also instruct RMAN to catalog any files in the FRA that the control file isn't currently aware of, like this:
RMAN> catalog recovery area;
Additionally, you can catalog specific files. This example instructs RMAN to add metadata to the control file for a
specific backup piece file:
RMAN> catalog backuppiece '/u01/O12C/rman/r159nv562v_1_1.bk';
