let RMAN backup run with low I/O workload — DURATION MINIMIZE LOAD

We can adjust RMAN backup to disk with low workload and longer time. Good thing for busy production environment from Oracle 10g.

RMAN backup options works for this purpose:
1) DURATION hh:mm -> Specifies a maximum time for a backup command to run. If a backup command does not complete in the specified duration, the backup being taken stops.
2) [PARTIAL][MINIMIZE (TIME|LOAD)] –> With disk backups, you can use MINIMIZE TIME run the backup at maximum speed (default) , or MINIMIZE LOAD to slow the rate of backup to lessen the load on the system. With MINIMIZE LOAD the backup will take the full specified duration.

Example
I purposely let RMAN backup run 2 hours, though it would take only 30mins there without any constraints.
RMAN>  backup device type disk format=’/myapp/u02/oradata/reportA/rman/reportA%U.bkp’ as compressed backupset duration 2:00 minimize load database;

Starting backup at 22-JUN-09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=123 devtype=DISK
channel ORA_DISK_1: starting compressed full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00004 name=/myapp/u02/oradata/reportA/users01.dbf

input datafile fno=00019 name=/myapp/u02/oradata/reportA/tools01.dbf
channel ORA_DISK_1: starting piece 1 at 22-JUN-09

SQL> select sid,program from v$session where paddr = (select addr from v$process where spid=12345);

       SID PROGRAM
———- ————————————————
       123 rman@oracle_node_1 (TNS V1-V3)

SQL> select time_remaining from v$session_longops where sid=123 and sofar<>totalwork;

TIME_REMAINING
————–
          5669
–After some time
SQL> select message,time_remaining from v$session_longops where sid=123 and sofar<>totalwork;

MESSAGE
——————————————————————————–
TIME_REMAINING
————–
RMAN: full datafile backup: Set Count 13521: 3442759 out of 0 Blocks done

RMAN: full datafile backup: Set Count 13521: 4858878 out of 4858880 Blocks done
             0

channel ORA_DISK_1: finished piece 1 at 22-JUN-09
piece handle=/myapp/u02/oradata/reportA/rman/reportA6hki7vbv_1_1.bkp tag=TAG20090622T170150 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 01:54:07
channel ORA_DISK_1: throttle time: 1:61:09
Finished backup at 22-JUN-09

RMAN> exit
Recovery Manager complete.

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About Pang

Oracle DBA working in database, fusion middleware and identity management and cloud.
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