(一) 当使用一个控制文件的备份恢复,例如下面的附图。使用备份控制文件恢复位置
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1) 创建測试表空间ts1及相关測试表(表空间为ts1)
SYS@ORCL>create tablespace ts1 datafile '/u01/app/oracle/oradata/ORCL/ts1.dbf' size 10m;
Tablespace created.
SYS@ORCL>create table scott.t(x int) tablespace ts1;
Table created.
SYS@ORCL>insert into scott.t select rownum from dual connect by rownum<=10;
10 rows created.
SYS@ORCL>commit;
Commit complete.
SYS@ORCL>
2) 通过RMAN备份ts1表空间和控制文件
RMAN> backup tablespace ts1 include current controlfile;
Starting backup at 17-JAN-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=141 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00006 name=/u01/app/oracle/oradata/ORCL/ts1.dbf
channel ORA_DISK_1: starting piece 1 at 17-JAN-13
channel ORA_DISK_1: finished piece 1 at 17-JAN-13
piece handle=/u01/app/oracle/flash_recovery_area/ORCL/backupset/2013_01_17/o1_mf_nnndf_TAG20130117T101646_8hgqrg9h_.bkp tag=TAG20130117T101646 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current control file in backupset
channel ORA_DISK_1: starting piece 1 at 17-JAN-13
channel ORA_DISK_1: finished piece 1 at 17-JAN-13
piece handle=/u01/app/oracle/flash_recovery_area/ORCL/backupset/2013_01_17/o1_mf_ncnnf_TAG20130117T101646_8hgqrhvd_.bkp tag=TAG20130117T101646 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 17-JAN-13
RMAN>
3) 删除t表部分记录
SYS@ORCL>delete scott.t where x>=6;
5 rows deleted.
SYS@ORCL>commit;
Commit complete.
SYS@ORCL>
4) 切换几次日志。让上面的动作归档(对于測试来说,意义不是特别的大)
SYS@ORCL>alter system switch logfile;
System altered.
SYS@ORCL>/
System altered.
SYS@ORCL>/
System altered.
SYS@ORCL>/
System altered.
SYS@ORCL>
5) 在users表空间上创建t1表
SYS@ORCL>create table scott.t1(x int) tablespace users;
Table created.
SYS@ORCL>insert into scott.t1 select rownum from dual connect by rownum<=2;
2 rows created.
SYS@ORCL>commit;
Commit complete.
SYS@ORCL>
6) 将表ts1改动为仅仅读模式
SYS@ORCL>alter tablespace ts1 read only;
Tablespace altered.
SYS@ORCL>select tablespace_name,status from dba_tablespaces where tablespace_name='TS1';
TABLESPACE_NAME STATUS
------------------------- ---------
TS1 READ ONLY
SYS@ORCL>select file_id,file_name,status,online_status from dba_data_files where tablespace_name='TS1';
FILE_ID FILE_NAME STATUS ONLINE_
---------- --------------------------------------------- --------- -------
6 /u01/app/oracle/oradata/ORCL/ts1.dbf AVAILABLE ONLINE
SYS@ORCL>
7) 删除ts1表空间数据文件和全部控制文件
SYS@ORCL>!rm /u01/app/oracle/oradata/ORCL/ts1.dbf
SYS@ORCL>!rm /u01/app/oracle/oradata/ORCL/*.ctl
8) 重新启动数据库到nomount状态
SYS@ORCL>shutdown abort;
ORACLE instance shut down.
SYS@ORCL>
SYS@ORCL>startup nomount;
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 96470608 bytes
Database Buffers 184549376 bytes
Redo Buffers 2973696 bytes
SYS@ORCL>
9) 通过RMAN备份的控制文件完毕控制文件的恢复,恢复完毕,数据库改动为mount
RMAN> restore controlfile from '/u01/app/oracle/flash_recovery_area/ORCL/backupset/2013_01_17/o1_mf_ncnnf_TAG20130117T101646_8hgqrhvd_.bkp';
Starting restore at 17-JAN-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=157 devtype=DISK
channel ORA_DISK_1: restoring control file
channel ORA_DISK_1: restore complete, elapsed time: 00:00:05
output filename=/u01/app/oracle/oradata/ORCL/control01.ctl
output filename=/u01/app/oracle/oradata/ORCL/control02.ctl
output filename=/u01/app/oracle/oradata/ORCL/control03.ctl
Finished restore at 17-JAN-13
RMAN> alter database mount;
database mounted
released channel: ORA_DISK_1
RMAN>
10) 恢复ts1表空间
RMAN> restore tablespace ts1;
Starting restore at 17-JAN-13
Starting implicit crosscheck backup at 17-JAN-13
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=157 devtype=DISK
Crosschecked 2 objects
Finished implicit crosscheck backup at 17-JAN-13
Starting implicit crosscheck copy at 17-JAN-13
using channel ORA_DISK_1
Finished implicit crosscheck copy at 17-JAN-13
searching for all files in the recovery area
cataloging files...
cataloging done
List of Cataloged Files
=======================
File Name: /u01/app/oracle/flash_recovery_area/ORCL/backupset/2013_01_17/o1_mf_ncnnf_TAG20130117T101646_8hgqrhvd_.bkp
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile backupset restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
restoring datafile 00006 to /u01/app/oracle/oradata/ORCL/ts1.dbf
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/flash_recovery_area/ORCL/backupset/2013_01_17/o1_mf_nnndf_TAG20130117T101646_8hgqrg9h_.bkp
channel ORA_DISK_1: restored backup piece 1
piece handle=/u01/app/oracle/flash_recovery_area/ORCL/backupset/2013_01_17/o1_mf_nnndf_TAG20130117T101646_8hgqrg9h_.bkp tag=TAG20130117T101646
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
Finished restore at 17-JAN-13
RMAN>
11) 表空间恢复完成。尝试open数据库
--当然。我们知道一定是无法open数据库的,由于控制文件恢复的是老版本号的
SYS@ORCL>!ls /u01/app/oracle/oradata/ORCL/ts1.dbf
/u01/app/oracle/oradata/ORCL/ts1.dbf
SYS@ORCL>alter database open;
alter database open
*
ERROR at line 1:
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
--提示resetlogs方式打开
SYS@ORCL>alter database open resetlogs;
alter database open resetlogs
*
ERROR at line 1:
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/u01/app/oracle/oradata/ORCL/system01.dbf'
--提示须要恢复1号数据文件
SYS@ORCL>recover datafile 1;
ORA-00283: recovery session canceled due to errors
ORA-01610: recovery using the BACKUP CONTROLFILE option must be done
--提示using BACKUP CONTROLFILE方式完毕恢复
SYS@ORCL>
12) using backup controlfile恢复数据库
注:假设要恢复到控制文件SCN以后的时间。这时候。就须要用using backup controlfile. 恢复就不会受“当前controlfile所纪录的SCN”的限制。
这时候的限制就来自于你的语句(until time , until scn),或者可用的archive log(until cancel)
SYS@ORCL>recover database using backup controlfile until cancel;
ORA-00279: change 493760 generated at 01/16/2013 17:10:46 needed for thread 1
ORA-00289: suggestion :
/u01/app/oracle/flash_recovery_area/ORCL/archivelog/2013_01_16/o1_mf_1_7_%u_.arc
ORA-00280: change 493760 for thread 1 is in sequence #7
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
--此处回车则是利用下一个归档日志文件进行恢复。只是在这里也能够输入CANCEL,表示恢复到此结束,不再使用后面的归档日志文件
……
--在恢复的过程中又出现了例如以下警告
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/u01/app/oracle/oradata/ORCL/system01.dbf'
SYS@ORCL>
13) 尝试再次resetlogs打开数据库
SYS@ORCL>alter database open resetlogs;
alter database open resetlogs
*
ERROR at line 1:
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '/u01/app/oracle/oradata/ORCL/system01.dbf'
SYS@ORCL>
14) 採用极端办法
注:此时仅仅能採取极端手段:隐含參数_allow_resetlogs_corruption强制启动数据库,设置此參数之后,在数据库Open过程中。Oracle会跳过某些一致性检查。从而使数据库可能跳过不一致状态,Open打开:
--查看隐藏參数_allow_resetlogs_corruption。默认值为false
SYS@ORCL>SELECT ksppstvl, ksppdesc
2 FROM x$ksppi x, x$ksppcv y
3 WHERE x.indx = y.indx
4 AND ksppinm = '_allow_resetlogs_corruption';
KSPPSTVL KSPPDESC
---------- --------------------------------------------------
FALSE allow resetlogs even if it will cause corruption
SYS@ORCL>
--将隐藏參数设置为true
SYS@ORCL>alter system set "_allow_resetlogs_corruption"=true scope=spfile;
System altered.
SYS@ORCL>
--因为是静态參数,重新启动数据库使其生效
SYS@ORCL>shutdown immediate;
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SYS@ORCL>
--数据库启动到mount状态
SYS@ORCL>startup mount;
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 83887696 bytes
Database Buffers 197132288 bytes
Redo Buffers 2973696 bytes
Database mounted.
SYS@ORCL>
15) 再次尝试open数据库。提示RESETLOGS方式open
SYS@ORCL>alter database open;
alter database open
*
ERROR at line 1:
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open
SYS@ORCL>
16) 数据库成功以resetlogs方式open
SYS@ORCL>alter database open resetlogs;
Database altered.
SYS@ORCL>
SYS@ORCL>select count(*) from scott.t;
COUNT(*)
----------
5
SYS@ORCL>select count(*) from scott.t1;
select count(*) from scott.t1
*
ERROR at line 1:
ORA-00942: table or view does not exist
SYS@ORCL>
17) 恢复參数,重新启动数据库
SYS@ORCL>alter system set "_allow_resetlogs_corruption"=false scope=spfile;
System altered.
SYS@ORCL>startup force;
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 88082000 bytes
Database Buffers 192937984 bytes
Redo Buffers 2973696 bytes
Database mounted.
Database opened.
SYS@ORCL>
5.1.1. 小结
假设在生产中使用了仅仅读表空间,那么切记,在改动为仅仅读以后,第一件事情就是备份的孩子,这将节省不必要的麻烦和损失。
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