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rman还原控制文件（三）

设置闪回区的情况下还原控制文件所使用的命令是相同的。然而如果当前数据库正在使用闪回区，RMAN通过对所有基于控制文件中的基于磁盘的备份和镜像副本和任何在闪回区中而不在还原的控制文件中的备份执行隐式的crosscheck来更新从备份中还原的控制文件。因此还原后的控制文件会完整的和精确的记录在闪回区中的所有备份和其它任何在备份该控制文件时所知道的备份。这提高了在数据库还原操作中的可用性。

下面来看一个使用闪回区还原控制文件的实例：1.环境检查，看是否已经启用闪回区与设置控制文件自动备份

SQL> show parameter db_recover  NAME                                 TYPE        VALUE ------------------------------------ ----------- ------------------------------ db_recovery_file_dest                string      /u01/app/oracle/flash_recovery_area db_recovery_file_dest_size           big integer 2G  SQL> select flashback_on from v$database;  FLASHBACK_ON ------------------ YES   RMAN> show controlfile autobackup;  RMAN configuration parameters are: CONFIGURE CONTROLFILE AUTOBACKUP ON;

从上面信息可知已经启用了闪回区并设置了控制文件自动备份

2.创建一个表空间,在数据库结构发生变化时，就会自动备份控制文件

SQL> create tablespace testbak datafile '/u01/app/oracle/oradata/test/testbak.dbf' size 10M  extent management local segment space management auto;  Tablespace created.

从alert日志中可以看到产生的控制文件自动备份的文件信息

create tablespace testbak datafile '/u01/app/oracle/oradata/test/testbak.dbf' size 10M  extent management local segment space management auto Mon Feb 02 00:17:28 CST 2015 Starting control autobackup Control autobackup written to DISK device         handle '/u01/app/oracle/flash_recovery_area/TEST/autobackup/2015_02_02/o1_mf_s_870567448_bdwndtqk_.bkp' Completed: create tablespace testbak datafile '/u01/app/oracle/oradata/test/testbak.dbf' size 10M  extent management local segment space management auto

其实控制文件和spfile同时被自动备份了

查看闪回区是否存在自动备份文件

[root@oracle11g 2015_02_02]# ls -lrt total 19360 -rw-r----- 1 oracle oinstall 9895936 Feb  2 00:17 o1_mf_s_870567448_bdwndtqk_.bkp

3.恢复控制文件

RMAN> restore controlfile  from autobackup;  Starting restore at 02-FEB-15 allocated channel: ORA_DISK_1 channel ORA_DISK_1: sid=148 devtype=DISK  recovery area destination: /u01/app/oracle/flash_recovery_area database name (or database unique name) used for search: TEST channel ORA_DISK_1: autobackup found in the recovery area channel ORA_DISK_1: autobackup found: /u01/app/oracle/flash_recovery_area/TEST/autobackup/2015_02_02/o1_mf_s_870567448_bdwndtqk_.bkp channel ORA_DISK_1: control file restore from autobackup complete Finished restore at 02-FEB-15

在上面的还原控制文件的过程可以看到如下内容说明是使用存储在闪回区中的控制文件自动备份来还原控制文件

channel ORA_DISK_1: autobackup found in the recovery area channel ORA_DISK_1: autobackup found: /u01/app/oracle/flash_recovery_area/TEST/autobackup/2015_02_02/o1_mf_s_870567448_bdwndtqk_.bkp

磁带备份在还原控制文件后不会自动执行crosscheck。如果正使用磁带备份，那么在还原控制文件并将数据库置于mount状态后，必须手工执行crosscheck.

RMAN> CROSSCHECK BACKUP DEVICE TYPE SBT;

4.执行完全恢复

RMAN> sql 'alter database mount';  sql statement: alter database mount released channel: ORA_DISK_1  RMAN> recover database;  Starting recover at 01-FEB-15 Starting implicit crosscheck backup at 01-FEB-15 allocated channel: ORA_DISK_1 channel ORA_DISK_1: sid=155 devtype=DISK Crosschecked 8 objects Finished implicit crosscheck backup at 01-FEB-15  Starting implicit crosscheck copy at 01-FEB-15 using channel ORA_DISK_1 Crosschecked 6 objects Finished implicit crosscheck copy at 01-FEB-15  searching for all files in the recovery area cataloging files... no files cataloged  using channel ORA_DISK_1  starting media recovery  archive log thread 1 sequence 3 is already on disk as file /u01/app/oracle/oradata/test/redo03.log archive log thread 1 sequence 4 is already on disk as file /u01/app/oracle/oradata/test/redo01.log archive log filename=/u01/app/oracle/oradata/test/redo03.log thread=1 sequence=3 archive log filename=/u01/app/oracle/oradata/test/redo01.log thread=1 sequence=4 media recovery complete, elapsed time: 00:00:01 Finished recover at 01-FEB-15    RMAN> sql 'alter database open resetlogs';  sql statement: alter database open resetlogs new incarnation of database registered in recovery catalog starting full resync of recovery catalog full resync complete

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