[每日一题] 11gOCP 1z0-053 :2013-10-15 duplexing of the backups............................60

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正确答案DB

 

这道题目没什么深入的原理，我们从答案入一一分析。

答案A不正确，多路复用可以备份在磁带和磁盘，根据经验答案不能确定是对是错的看到这种还有“only”只有唯一的单词，一般是错的。

 

答案B正确，镜像拷贝不支持多路径复用，实验加以验证，看下面实验：

 

RMAN> copy datafile 10 to \'/backup/disk1/df10_1\',\'/backup/disk1/df10_2\';

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01009: syntax error: found "single-quoted-string": expecting one of: "archivelog, backup, controlfilecopy, current, datafilecopy, datafile"
RMAN-01007: at line 1 column 44 file: standard input

RMAN> copy datafile 10 to \'/backup/disk1/df10_1\';

Starting backup at 16-OCT-13
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile copy
input datafile file number=00010 name=/u01/app/oracle/oradata/ocm/tp2.dbf
output file name=/backup/disk1/df10_1 tag=TAG20131016T001904 RECID=5 STAMP=828922746
channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:03
Finished backup at 16-OCT-13

Starting Control File and SPFILE Autobackup at 16-OCT-13
piece handle=/backup/rman/c-2206937749-20131016-01 comment=NONE
Finished Control File and SPFILE Autobackup at 16-OCT-13

答案C不正确，并行度与镜像拷数无关，实验加以验证，看下面实验：

RMAN> show all;

RMAN configuration parameters for database with db_unique_name OCM are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO \'/backup/rman/%F\';
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1;
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT   \'%U\';
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 \'/u01/app/oracle/product/11.2.0/dbs/snapcf_ocm.f\'; # default

RMAN> CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 2;

old RMAN configuration parameters:
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1;
new RMAN configuration parameters:
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 2;
new RMAN configuration parameters are successfully stored

CONFIGUREDEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET;--并行度是1也没关系

CONFIGUREDATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 2;--备份集多路径

对10文件多路径备份，这里我们的并行度为1，备份集多径路2，此时并行度与多径路不一样，也可以备份。

RMAN> report schema;    

Report of database schema for database with db_unique_name OCM

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    730      SYSTEM               ***     /u01/app/oracle/oradata/ocm/system01.dbf
2    710      SYSAUX               ***     /u01/app/oracle/oradata/ocm/sysaux01.dbf
3    110      UNDOTBS1             ***     /u01/app/oracle/oradata/ocm/undotbs01.dbf
4    5        USERS                ***     /u01/app/oracle/oradata/ocm/users01.dbf
5    345      EXAMPLE              ***     /u01/app/oracle/oradata/ocm/example01.dbf
6    100      GYJ                  ***     /u01/app/oracle/oradata/ocm/gyj01.dbf
7    50       GYJ                  ***     /u01/app/oracle/oradata/ocm/gyj02.dbf
8    10       TP1                  ***     /u01/app/oracle/oradata/ocm/tp01.dbf
9    10       MRKT                 ***     /u01/app/oracle/oradata/ocm/mrkt01.dbf
10   100      TP2                  ***     /u01/app/oracle/oradata/ocm/tp2.dbf

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    20       TEMP                 32767       /u01/app/oracle/oradata/ocm/temp01.dbf
2    10       TEMP1                10          /u01/app/oracle/oradata/ocm/temp02.dbf
3    10       TEMP4                10          /u01/app/oracle/oradata/ocm/temp04.dbf

RMAN> backup datafile 10 format \'/backup/disk1/%U\',\'/backup/disk2/%U\';

Starting backup at 16-OCT-13
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00010 name=/u01/app/oracle/oradata/ocm/tp2.dbf
channel ORA_DISK_1: starting piece 1 at 16-OCT-13
channel ORA_DISK_1: finished piece 1 at 16-OCT-13 with 2 copies and tag TAG20131016T001426
piece handle=/backup/disk1/1gomgmj2_1_1 comment=NONE
piece handle=/backup/disk2/1gomgmj2_1_2 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 16-OCT-13

Starting Control File and SPFILE Autobackup at 16-OCT-13
piece handle=/backup/rman/c-2206937749-20131016-00 comment=NONE
Finished Control File and SPFILE Autobackup at 16-OCT-13

答案D正确，多路复制可以备份在磁盘或着磁带上，但是不能同时备份在磁盘和着磁带上。

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