從ORACLE9i開始，rman支持基于數據庫的恢復，這一功能有很大的好處，既不影響業務，甚至不影響有壞塊的數據文件，恢復可以是在線恢復。但是恢復是完全恢復，所以要求完整的備份。

下面測試：

1. 對數據庫進行完整備份

   Rman>backup database;

2. 破壞數據

   參看日志《RMAN進行基于數據塊的恢復》

3. 使用rman驗證數據文件

   RMAN> backup validate datafile 5;

   Starting backup at 29-AUG-14

   using target database control file instead of recovery catalog

   allocated channel: ORA_DISK_1

   channel ORA_DISK_1: sid=159 devtype=DISK

   allocated channel: ORA_DISK_2

   channel ORA_DISK_2: sid=139 devtype=DISK

   channel ORA_DISK_1: starting full datafile backupset

   channel ORA_DISK_1: specifying datafile(s) in backupset

   input datafile fno=00005 name=/opt/oracle/oradata/orcla/xzsp.dbf

   channel ORA_DISK_1: backup set complete, elapsed time: 00:00:07

   Finished backup at 29-AUG-14

   警告日志和數據庫中都會記錄損壞的數據，如下

   SQL> select * from v$database_block_corruption ;

   FILE# BLOCK# BLOCKS CORRUPTION_CHANGE# CORRUPTIO

   ---------- ---------- ---------- ------------------ ---------

   5 49316 1 0 CORRUPT

4. 通過備份基于數據快級的恢復

   RMAN> blockrecover datafile 5 block 49316 from backupset;

   Starting blockrecover at 29-AUG-14

   using channel ORA_DISK_1

   using channel ORA_DISK_2

   ?

   channel ORA_DISK_1: restoring block(s)

   channel ORA_DISK_1: specifying block(s) to restore from backup set

   restoring blocks of datafile 00005

   channel ORA_DISK_1: reading from backup piece /opt/oracle/flash_recovery_area1/ORCLA/backupset/2014_08_29/o1_mf_nnndf_TAG20140829T032828_9zz0px68_.bkp

   channel ORA_DISK_1: restored block(s) from backup piece 1

   piece handle=/opt/oracle/flash_recovery_area1/ORCLA/backupset/2014_08_29/o1_mf_nnndf_TAG20140829T032828_9zz0px68_.bkp tag=TAG20140829T032828

   channel ORA_DISK_1: block restore complete, elapsed time: 00:00:26

   ?

   starting media recovery

   ?

   archive log thread 1 sequence 5 is already on disk as file /opt/oracle/flash_recovery_area1/ORCLA/archivelog/2014_08_29/o1_mf_1_5_9zz2mqwo_.arc

   archive log thread 1 sequence 6 is already on disk as file /opt/oracle/flash_recovery_area1/ORCLA/archivelog/2014_08_29/o1_mf_1_6_9zz2v3jj_.arc

   archive log thread 1 sequence 7 is already on disk as file /opt/oracle/flash_recovery_area1/ORCLA/archivelog/2014_08_29/o1_mf_1_7_9zz3hfff_.arc

   media recovery complete, elapsed time: 00:00:01

   Finished blockrecover at 29-AUG-14

5. 清楚壞塊記錄

   SQL> select * from v$database_block_corruption ;

   FILE# BLOCK# BLOCKS CORRUPTION_CHANGE# CORRUPTIO

   ---------- ---------- ---------- ------------------ ---------

   5 49316 1 0 CORRUPT

   RMAN> backup validate datafile 5;

   Starting backup at 29-AUG-14

   using channel ORA_DISK_1

   using channel ORA_DISK_2

   channel ORA_DISK_1: starting full datafile backupset

   channel ORA_DISK_1: specifying datafile(s) in backupset

   input datafile fno=00005 name=/opt/oracle/oradata/orcla/xzsp.dbf

   channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03

   Finished backup at 29-AUG-14

   SQL> select * from v$database_block_corruption ;

   ?

   no rows selected

   ?

   注意：

   但有些情況下,BLOCKRECOVER未必可以恢復得了:

   [oracle@ique datafile]$ sqlplus mayp/mayp

   SQL*Plus: Release 10.1.0.5.0 – Production on Mon Jul 14 17:08:06 2008

   Copyright (c) 1982, 2005, Oracle. All rights reserved.

   Connected to:

   Oracle Database 10g Enterprise Edition Release 10.1.0.5.0 – Production

   With the Partitioning, OLAP and Data Mining options

   SQL> select count(*) from mssm;

   select count(*) from mssm

   *

   ERROR at line 1:

   ORA-01578: ORACLE data block corrupted (file # 5, block # 9)

   ORA-01110: data file 5: '/data/mayp/MAYP/datafile/o1_mf_mssm_4789hznr_.dbf'

   [oracle@ique datafile]$ rman target /

   Recovery Manager: Release 10.1.0.5.0 – Production

   Copyright (c) 1995, 2004, Oracle. All rights reserved.

   connected to target database: MAYP (DBID=412172232)

   RMAN> blockrecover datafile 5 block 9;

   Starting blockrecover at 14-JUL-08

   using target database controlfile instead of recovery catalog

   allocated channel: ORA_DISK_1

   channel ORA_DISK_1: sid=378 devtype=DISK

   RMAN-00571: ===========================================================

   RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

   RMAN-00571: ===========================================================

   RMAN-03002: failure of blockrecover command at 07/14/2008 17:08:37

   ORA-01455: converting column overflows integer datatype

   RMAN-06010: error while looking up datafile: 5

   這個塊損壞已經嚴重破壞了數據的存放規律,發生了邏輯損壞,所以blockrecover沒辦法恢復,必須首先restore這個文件然后通過recvoer命令進行恢復.

   通過常規方法恢復這個錯誤:

   RMAN> sql 'alter database datafile 5 offline';

   sql statement: alter database datafile 5 offline

   RMAN> restore datafile 5;

   Starting restore at 14-JUL-08

   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 00005 to /data/mayp/MAYP/datafile/o1_mf_mssm_4789hznr_.dbf

   channel ORA_DISK_1: restored backup piece 1

   piece handle=/home/oracle/product/10.2/dbs/full_2_MAYP.rman tag=TAG20080714T152854

   channel ORA_DISK_1: restore complete

   Finished restore at 14-JUL-08

   RMAN> recover datafile 5;

   Starting recover at 14-JUL-08

   using channel ORA_DISK_1

   starting media recovery

   media recovery complete

   Finished recover at 14-JUL-08

   RMAN> sql 'alter database datafile 5 online';

   sql statement: alter database datafile 5 online

   RMAN> exit

   BLOCKRECOVER 的使用限制:

   1、數據庫必須在ARCHIVELOG模式下才可以使用這個功能;

   2、數據庫必須是mount或open狀態;

   3、不能對一個offline的datafile進行BLOCKRECOVER;

   4、blcokrecover需要通過一個full backups 恢復datra block,不能使用incremental backups進行錯誤恢復;

   5、blockrecover不能跨越archivelog丟失或損壞,也就是說在恢復的過程中,不能丟失需要的歸檔日志;

   6、blockrecover不能恢復邏輯壞塊,邏輯壞塊必須首先restore損壞的數據文件,然后在用recover進行恢復;

   7、blockrecvoer不能恢復file header block.(block=1).

RMAN進行基于數據塊的恢復