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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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