oracle数据库灾难恢复

环境：oracle12c

执行恢复
数据库打开条件
1)所有控制文件存在并且一致性
2)所有数据文件(ONLINE状态)存在并且一致性
3)每个重做日志组至少有一个成员是存在

DRA Data Recovery Advisor   列出故障、提供修复的建议、执行修复

常见的故障恢复

1、loss of password file   --密码文件丢失

rman的不备份的password file
[oracle@12c dbs]$ ll $ORACLE_HOME/dbs/orapworcl    --密码文件路径
-rw-r-----. 1 oracle oinstall 4096 Jul  6 15:46 /u01/app/oracle/product/12.2.0.1/db_1/dbs/orapworcl
[oracle@12c dbs]$ file orapworcl 
orapworcl: data
[oracle@12c dbs]$ rm -vf orapworcl     --删除密码文件
[oracle@12c dbs]$ sqlplus / as sysdba  --使用os系统认证可以登录OK
[oracle@12c dbs]$ sqlplus hr/hr@192.168.95.150:1521/orcl.oracle.com  --OK
--故障提现，下面方式不能登录
[oracle@12c dbs]$ sqlplus sys/oracle@orcl as sysdba  TNS方式
[oracle@12c dbs]$ sqlplus sys/oracle@192.168.95.150:1521/orcl.oracle.com as sysdba  ---EZConnection方式
SQL> grant sysdba to hr;
grant sysdba to hr
*
ERROR at line 1:
ORA-01994: GRANT failed: password file missing or disabled
通过工具orapwd工具来重新创建密码文件
[oracle@12c dbs]$ which orapwd
/u01/app/oracle/product/12.2.0.1/db_1/bin/orapwd
[oracle@12c dbs]$ orapwd --help

[oracle@12c dbs]$ orapwd file=$ORACLE_HOME/dbs/orapworcl password=yinhe  format=12  --format指定12c 用户要多几个比以前版本
[oracle@12c dbs]$ ll orapworcl 
-rw-r-----. 1 oracle oinstall 2048 Jul 13 16:10 orapworcl

[oracle@12c dbs]$ sqlplus sys/yinhe@orcl as sysdba
[oracle@12c dbs]$ sqlplus sys/yinhe@192.168.95.150:1521/orcl.oracle.com  as sysdba
SQL> grant sysdba to hr;

2、loss of a control file  --控制文件丢失

控制文件保存在文件系统或者ASM磁盘中
show parameter control_files
NAME          TYPE   VALUE                                                                                        
------------- ------ -------------------------------------------------------------------------------------------- 
control_files string /u01/app/oracle/oradata/orcl/control01.ctl, /u02/app/oracle/fast_recovery/ORCL/control02.ctl 

SELECT value FROM v$parameter2
WHERE name='control_files';
/u01/app/oracle/oradata/orcl/control01.ctl
/u02/app/oracle/fast_recovery/ORCL/control02.ctl
模拟丢失一个控制文件
[oracle@12c ORCL]$ rm -vf control02.ctl 
SQL> shutdown immediate;
ORA-00210: cannot open the specified control file
ORA-00202: control file: '/u02/app/oracle/fast_recovery/ORCL/control02.ctl'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
SQL> shutdown abort;

[oracle@12c dbs]$ sqlplus  / as sysdba
SQL> startup nomount;
SQL> ALTER DATABASE MOUNT;
ALTER DATABASE MOUNT
*
ERROR at line 1:
ORA-00205: error in identifying control file, check alert log for more info
SQL> SELECT status FROM v$instance;   --当前数据库实例处于nomount状态
STATUS
------------
STARTED

[oracle@12c trace]$ tail -f alert_orcl.log 
Linux-x86_64 Error: 2: No such file or directory
Additional information: 7
ORA-205 signalled during: ALTER DATABASE MOUNT...
2020-07-13T16:22:48.827023+08:00
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_m000_21661.trc:
ORA-00202: control file: '/u02/app/oracle/fast_recovery/ORCL/control02.ctl'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
[oracle@12c dbs]$ cp /u01/app/oracle/oradata/orcl/control01.ctl /u02/app/oracle/fast_recovery/ORCL/control02.ctl --控制文件多路复用，直接拷贝可用，不用再做恢复
SQL> ALTER DATABASE MOUNT;
Database altered.
SQL> ALTER DATABASE OPEN;
Database altered.


[oracle@12c ORCL]$ export NLS_DATE_FORMAT='yyyy-mm-dd hh24:mi:ss'
[oracle@12c ORCL]$ echo $NLS_DATE_FORMAT

3)loss of all control file
SQL> shutdown abort;
sql> startup nomount;
RMAN> restore controlfile from '/u02/app/oracle/fast_recovery/ORCL/autobackup/2020_07_13/o1_mf_s_1045667839_hjr2mzpr_.bkp'; --还原以前的文件，和数据库记录不一致，需要recover
Starting restore at 2020-07-13 16:35:59
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=37 device type=DISK
channel ORA_DISK_1: restoring control file
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
output file name=/u01/app/oracle/oradata/orcl/control01.ctl
output file name=/u02/app/oracle/fast_recovery/ORCL/control02.ctl
Finished restore at 2020-07-13 16:36:01
RMAN> ALTER DATABASE MOUNT;
RMAN> recover database;
RMAN> alter database open resetlogs;

4)loss of a redo log file
5)loss of all redo log group file
6)loss of temporary datafile
7)loss of a datafile in noarchivelog mode
8)loss of a noncritical data file in archivelog mode
9)loss of a system-critical data file in archivelog mode
10)loss of a spifle