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RMAN backup parallelism with section sizes

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Backup parallelism with section sizes

 

Prior to 11G R1 we could achieve RMAN parallelism by allocating multiple channels. This remains true. But even you allocated 16 channels only one channel was used per data file. If you had only a few very large data files you still could not parallel your backup as much as you wanted.

An 11G R1 enhancement is that you can parallel the backup of those few very large data files. You only have to specify a section size. RMAN interpret the section size based upon the size of the data files meaning that the data file to backup will be divided into n times the sections size. ( but not more than 256 sections )

 

 

RMAN> backup section size 50M tablespace system;


Starting backup at 23-JUN-09
using channel ORA_DISK_1
using channel ORA_DISK_2
using channel ORA_DISK_3
using channel ORA_DISK_4
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=C:\ORACLE\PRODUCT\11.1.0\ORADATA\PLATINUM\DATAFILE\O1_MF_SYSTEM_0LK30K1Q_.DBF
backing up blocks 1 through 6400
channel ORA_DISK_1: starting piece 1 at 23-JUN-09
channel ORA_DISK_2: starting compressed full datafile backup set
channel ORA_DISK_2: specifying datafile(s) in backup set
channel ORA_DISK_3: starting compressed full datafile backup set
channel ORA_DISK_3: specifying datafile(s) in backup set
including current SPFILE in backup set
channel ORA_DISK_3: starting piece 1 at 23-JUN-09
channel ORA_DISK_4: starting compressed full datafile backup set
channel ORA_DISK_4: specifying datafile(s) in backup set
input datafile file number=00001 name=C:\ORACLE\PRODUCT\11.1.0\ORADATA\PLATINUM\DATAFILE\O1_MF_SYSTEM_0LK30K1Q_.DBF
backing up blocks 6401 through 12800
channel ORA_DISK_4: starting piece 2 at 23-JUN-09
including current control file in backup set
channel ORA_DISK_2: starting piece 1 at 23-JUN-09
channel ORA_DISK_3: finished piece 1 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NNSNF_TAG20090623T225432_542J8F07_.BKP tag=TAG20090623T225432 comment=NONE
channel ORA_DISK_3: backup set complete, elapsed time: 00:00:07
channel ORA_DISK_3: starting compressed full datafile backup set
channel ORA_DISK_3: specifying datafile(s) in backup set
input datafile file number=00001 name=C:\ORACLE\PRODUCT\11.1.0\ORADATA\PLATINUM\DATAFILE\O1_MF_SYSTEM_0LK30K1Q_.DBF
backing up blocks 12801 through 19200
channel ORA_DISK_3: starting piece 3 at 23-JUN-09
channel ORA_DISK_1: finished piece 1 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NNNDF_TAG20090623T225432_542J89VS_.BKP tag=TAG20090623T225432 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:10
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=C:\ORACLE\PRODUCT\11.1.0\ORADATA\PLATINUM\DATAFILE\O1_MF_SYSTEM_0LK30K1Q_.DBF
backing up blocks 19201 through 25600
channel ORA_DISK_1: starting piece 4 at 23-JUN-09
channel ORA_DISK_2: finished piece 1 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NCNNF_TAG20090623T225432_542J8KD3_.BKP tag=TAG20090623T225432 comment=NONE

cut

 

backing up blocks 89601 through 96000
channel ORA_DISK_1: starting piece 15 at 23-JUN-09
channel ORA_DISK_2: finished piece 12 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NNNDF_TAG20090623T225432_542J9F6G_.BKP tag=TAG20090623T225432 comment=NONE
channel ORA_DISK_2: backup set complete, elapsed time: 00:00:10
channel ORA_DISK_2: starting compressed full datafile backup set
channel ORA_DISK_2: specifying datafile(s) in backup set
input datafile file number=00001 name=C:\ORACLE\PRODUCT\11.1.0\ORADATA\PLATINUM\DATAFILE\O1_MF_SYSTEM_0LK30K1Q_.DBF
backing up blocks 96001 through 98560
channel ORA_DISK_2: starting piece 16 at 23-JUN-09
channel ORA_DISK_3: finished piece 13 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NNNDF_TAG20090623T225432_542J9GBG_.BKP tag=TAG20090623T225432 comment=NONE
channel ORA_DISK_3: backup set complete, elapsed time: 00:00:09
channel ORA_DISK_4: finished piece 14 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NNNDF_TAG20090623T225432_542J9HRY_.BKP tag=TAG20090623T225432 comment=NONE
channel ORA_DISK_4: backup set complete, elapsed time: 00:00:08
channel ORA_DISK_2: finished piece 16 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NNNDF_TAG20090623T225432_542J9QVM_.BKP tag=TAG20090623T225432 comment=NONE
channel ORA_DISK_2: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: finished piece 15 at 23-JUN-09
piece handle=C:\ORACLE\PRODUCT\11.1.0\FLASH_RECOVERY_AREA\PLATINUM\BACKUPSET\2009_06_23\O1_MF_NNNDF_TAG20090623T225432_542J9Q65_.BKP tag=TAG20090623T225432 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 23-JUN-09

 

This command is also interesting

 

RMAN> backup as compressed backupset section size 200M database;