RMAN深入解析之--BlockRecover恢复坏块

RMAN深入解析之--BlockRecover恢复坏块案例环境：操作系统：RedHatEL5Oracle：Oracle11gR2案例描述：通过块介质恢复（BlockMediaRecover:BMR)执行块级别的恢复操

RMAN深入解析之--BlockRecover恢复坏块

案例环境：

操作系统：RedHat EL5

Oracle：  Oracle 11gR2

案例描述：

   通过块介质恢复（Block Media Recover:BMR)执行块级别的恢复操作来修复Oracle数据库上的逻辑或物理上损坏的数据块。

1、模拟数据块被破坏

10:26:48 SYS@ prod>conn scott/tiger Connected. 10:26:51 SCOTT@ prod>select * from tab; TNAME                          TABTYPE  CLUSTERID ------------------------------ ------- ---------- BONUS                          TABLE DEPT                           TABLE EMP                            TABLE EMP1                           TABLE SALGRADE                       TABLE Elapsed: 00:00:00.10 10:26:55 SCOTT@ prod> 10:27:37 SYS@ prod>desc dba_segments  Name                                                              Null?    Type    ----------------------------------------------------------------- -------- -------------  OWNER                                                                      VARCHAR2(30)  SEGMENT_NAME                                                               VARCHAR2(81)  PARTITION_NAME                                                             VARCHAR2(30)  SEGMENT_TYPE                                                               VARCHAR2(18)  SEGMENT_SUBTYPE                                                            VARCHAR2(10)  TABLESPACE_NAME                                                            VARCHAR2(30)  HEADER_FILE                                                                NUMBER  HEADER_BLOCK                                                               NUMBER  BYTES                                                                      NUMBER  BLOCKS                                                                     NUMBER  EXTENTS                                                                    NUMBER  INITIAL_EXTENT                                                             NUMBER  NEXT_EXTENT                                                                NUMBER  MIN_EXTENTS                                                                NUMBER  MAX_EXTENTS                                                                NUMBER  MAX_SIZE                                                                   NUMBER  RETENTION                                                                  VARCHAR2(7)  MINRETENTION                                                               NUMBER  PCT_INCREASE                                                               NUMBER  FREELISTS                                                                  NUMBER  FREELIST_GROUPS                                                            NUMBER  RELATIVE_FNO                                                               NUMBER  BUFFER_POOL                                                                VARCHAR2(7)  FLASH_CACHE                                                                VARCHAR2(7)  CELL_FLASH_CACHE                                                           VARCHAR2(7) 10:27:41 SYS@ prod>col segment_name for a20        10:27:59 SYS@ prod>select owner,segment_name,SEGMENT_TYPE,HEADER_BLOCK from dba_segments       10:29:06   2   where owner='SCOTT' and segment_name='EMP1'; OWNER                          SEGMENT_NAME         SEGMENT_TYPE       HEADER_BLOCK ------------------------------ -------------------- ------------------ ------------ SCOTT                          EMP1                 TABLE                       170

     通过以上查询，可以知道EMP1 table的segment header block为170；利用Uedit32，打开数据文件（users01.dbf)进行编辑破坏！

以下是计算block 170和block 171在Uedit32编辑中的offset：

10:29:24 SYS@ prod>select to_char(170*8*1024, 'xxxxxxxxxxxxxxxxxxxxx') from dual;

TO_CHAR(170*8*1024,'XX

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

                154000

10:30:27 SYS@ prod>select to_char(171*8*1024, 'xxxxxxxxxxxxxxxxxxxxx') from dual;

TO_CHAR(171*8*1024,'XX

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

                156000

以下是Uedit32编辑users01.dbf图片：

通过转储数据块验证：

10:30:37 SYS@ prod>alter system dump datafile 4 block 170;

System altered.

 

[oracle@rh6 ~]$ ls -lt /u01/app/oracle/diag/rdbms/prod/prod/trace/|more