multisection backup是Oracle11g（确切的说是从11.1.0.6开始）的新特性，见mos文章
下面来做实验：
[oracle@rhel63single ~]$ rman target / Recovery Manager: Release 11.2.0.4.0 - Production on Thu Feb 19 01:07:28 2015 Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved. connected to target database: TEST (DBID=2106028980) RMAN> report schema; using target database control file instead of recovery catalog Report of database schema for database with db_unique_name TEST List of Permanent Datafiles =========================== File Size(MB) Tablespace RB segs Datafile Name ---- -------- -------------------- ------- ------------------------ 1 800 SYSTEM *** /u01/app/oracle/oradata/test/system01.dbf 2 3310 SYSAUX *** /u01/app/oracle/oradata/test/sysaux01.dbf 3 240 UNDOTBS1 *** /u01/app/oracle/oradata/test/undotbs01.dbf 4 7 USERS *** /u01/app/oracle/oradata/test/users01.dbf 5 50 TENTBS *** /u01/app/oracle/oradata/test/ten01.dbf 6 5 TB_TEST *** /u01/app/oracle/oradata/test/tb_test_01.dbf 7 500 TS1 *** /u01/app/oracle/oradata/test/ts1.dbf 8 500 TS2 *** /u01/app/oracle/oradata/test/ts2.dbf 9 50 TEST *** /u01/app/oracle/oradata/test/test01.dbf 10 50 TEST_UNI_SZ_2M *** /u01/app/oracle/oradata/test/test_uni_sz_2m_01.dbf 11 200 TEST_UNI_SZ_1M *** /u01/app/oracle/oradata/test/test_uni_sz_1m_01.dbf List of Temporary Files ======================= File Size(MB) Tablespace Maxsize(MB) Tempfile Name ---- -------- -------------------- ----------- -------------------- 1 157 TEMP 32767 /u01/app/oracle/oradata/test/temp01.dbf RMAN> show all; RMAN configuration parameters for database with db_unique_name TEST are: CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default CONFIGURE BACKUP OPTIMIZATION OFF; # default CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default CONFIGURE MAXSETSIZE TO UNLIMITED; # default CONFIGURE ENCRYPTION FOR DATABASE OFF; # default CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default CONFIGURE COMPRESSION ALGORITHM 'BASIC' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE ; # default CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u02/app/oracle/product/11.2.0.4/db_1/dbs/snapcf_test.f'; # default RMAN> backup section size 300m datafile 1 format '/u02/%U'; Starting backup at 19-FEB-15 allocated channel: ORA_DISK_1 channel ORA_DISK_1: SID=133 device type=DISK channel ORA_DISK_1: starting full datafile backup set channel ORA_DISK_1: specifying datafile(s) in backup set input datafile file number=00001 name=/u01/app/oracle/oradata/test/system01.dbf ---->system01.dbf backing up blocks 1 through 38400--------------------------------------------------->注意此处 channel ORA_DISK_1: starting piece 1 at 19-FEB-15 channel ORA_DISK_1: finished piece 1 at 19-FEB-15 piece handle=/u02/06pvkh2l_1_1 tag=TAG20150219T011148 comment=NONE------------------>生成的backuppiece channel ORA_DISK_1: backup set complete, elapsed time: 00:00:28 channel ORA_DISK_1: starting full datafile backup set channel ORA_DISK_1: specifying datafile(s) in backup set input datafile file number=00001 name=/u01/app/oracle/oradata/test/system01.dbf ---->system01.dbf backing up blocks 38401 through 76800----------------------------------------------->注意此处 channel ORA_DISK_1: starting piece 2 at 19-FEB-15 channel ORA_DISK_1: finished piece 2 at 19-FEB-15 piece handle=/u02/06pvkh2l_2_1 tag=TAG20150219T011148 comment=NONE------------------>生成的backuppiece channel ORA_DISK_1: backup set complete, elapsed time: 00:00:16 channel ORA_DISK_1: starting full datafile backup set channel ORA_DISK_1: specifying datafile(s) in backup set input datafile file number=00001 name=/u01/app/oracle/oradata/test/system01.dbf ---->system01.dbf backing up blocks 76801 through 102400---------------------------------------------->注意此处 channel ORA_DISK_1: starting piece 3 at 19-FEB-15 channel ORA_DISK_1: finished piece 3 at 19-FEB-15 piece handle=/u02/06pvkh2l_3_1 tag=TAG20150219T011148 comment=NON------------------>生成的backuppiece channel ORA_DISK_1: backup set complete, elapsed time: 00:00:16 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 including current SPFILE in backup set channel ORA_DISK_1: starting piece 1 at 19-FEB-15 channel ORA_DISK_1: finished piece 1 at 19-FEB-15 piece handle=/u02/09pvkh4o_1_1 tag=TAG20150219T011148 comment=NONE --->这个backuppiece是控制文件的自动备份，因为datafile1的备份会自动触发控制文件的备份。 channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01 Finished backup at 19-FEB-15 RMAN>
一个datafile，使用backup section size 方式来做备份，分成了3个backuppiece，由于上述实验是在一个channel内完成的，体现不出来多个channel 同时干活的优势，因此，伙会在另外一片文章中分配2个channel 来备份该datafile。
原文地址：http://blog.csdn.net/msdnchina/article/details/43915407
