696. Examine the following command for RMAN backup:
Which statement Is true regarding the approach in the command?
A.The RMAN multiplexing level is 4.
B.It is the use of asynchronous I/O by RMAN.
C.It is a case of parallelization of the backup set.
D.It is an implementation of a multisection backup.
Answer: C
答案解析：
从以上图片中以及以下的实验中看出，分了三个通道并行备份。
图中1,4,5数据文件使用通道C1，2，3，9数据文件使用通道C2，6,7,8使用通道C3，
这三个通道并行执行备份。
RMAN> report schema;
using target database control file instead of recovery catalog
Report of database schema for database with db_unique_name RCAT1028
List of Permanent Datafiles
===========================
File Size(MB) Tablespace RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1 710 SYSTEM *** +DATA/rcat1028/datafile/system.262.830015445
2 660 SYSAUX *** +DATA/rcat1028/datafile/sysaux.261.830015451
3 80 UNDOTBS1 *** +DATA/rcat1028/datafile/undotbs1.265.830015451
4 5 USERS *** +DATA/rcat1028/datafile/users.259.830015453
5 15 RCAT *** +DATA/rcat01.dbf
List of Temporary Files
=======================
File Size(MB) Tablespace Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1 29 TEMP 32767 +DATA/rcat1028/tempfile/temp.256.830015677
RMAN> run{
2> allocate channel c1 device type disk;
3> allocate channel c2 device type disk;
4> allocate channel c3 device type disk;
5> backup
6> incremental level=0
7> (datafile 1,2 channel c1)
8> (datafile 3,4 channel c2)
9> (datafile 5 channel c3);
10> sql 'alter system archive log current';
11> }
allocated channel: c1
channel c1: SID=192 device type=DISK
allocated channel: c2
channel c2: SID=221 device type=DISK
allocated channel: c3
channel c3: SID=8 device type=DISK
Starting backup at 05-NOV-13
channel c1: starting incremental level 0 datafile backup set
channel c1: specifying datafile(s) in backup set
input datafile file number=00001 name=+DATA/rcat1028/datafile/system.262.830015445
input datafile file number=00002 name=+DATA/rcat1028/datafile/sysaux.261.830015451
channel c1: starting piece 1 at 05-NOV-13
channel c2: starting incremental level 0 datafile backup set
channel c2: specifying datafile(s) in backup set
input datafile file number=00003 name=+DATA/rcat1028/datafile/undotbs1.265.830015451
input datafile file number=00004 name=+DATA/rcat1028/datafile/users.259.830015453
channel c2: starting piece 1 at 05-NOV-13
channel c3: starting incremental level 0 datafile backup set
channel c3: specifying datafile(s) in backup set
input datafile file number=00005 name=+DATA/rcat01.dbf
channel c3: starting piece 1 at 05-NOV-13
channel c3: finished piece 1 at 05-NOV-13
piece handle=+RECOVERY/rcat1028/backupset/2013_11_05/nnndn0_tag20131105t222104_0.276.830730067 tag=TAG20131105T222104 comment=NONE
channel c3: backup set complete, elapsed time: 00:00:16
channel c2: finished piece 1 at 05-NOV-13
piece handle=+RECOVERY/rcat1028/backupset/2013_11_05/nnndn0_tag20131105t222104_0.275.830730067 tag=TAG20131105T222104 comment=NONE
channel c2: backup set complete, elapsed time: 00:00:19
channel c1: finished piece 1 at 05-NOV-13
piece handle=+RECOVERY/rcat1028/backupset/2013_11_05/nnndn0_tag20131105t222104_0.261.830730065 tag=TAG20131105T222104 comment=NONE
channel c1: backup set complete, elapsed time: 00:03:19
channel c1: starting incremental level 0 datafile backup set
channel c1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel c1: starting piece 1 at 05-NOV-13
channel c1: finished piece 1 at 05-NOV-13
piece handle=+RECOVERY/rcat1028/backupset/2013_11_05/ncsnn0_tag20131105t222104_0.277.830730269 tag=TAG20131105T222104 comment=NONE
channel c1: backup set complete, elapsed time: 00:00:04
Finished backup at 05-NOV-13
sql statement: alter system archive log current
released channel: c1
released channel: c2
released channel: c3