利用RMAN修復資料檔案中的壞塊

lygle發表於2013-04-03
利用RMAN修復資料檔案中的壞塊
1、建立測試表：
SQL> create table tab_dbv tablespace ghost as select * from dba_objects;
表已建立。
SQL> insert into tab_dbv select * from tab_dbv;
已建立50363行。
SQL> insert into tab_dbv select * from tab_dbv;
已建立100726行。
SQL> commit;
提交完成。
2、查詢tab_dbv的塊頭：
SQL> select segment_name,header_block from dba_segments where segment_name='TAB_DBV';
SEGMENT_NAME              HEADER_BLOCK
------------------------- ------------
TAB_DBV                             35
SQL> select to_char(35*8*1024,'xxxxxxxxxxxxxxxxxxxxxx') from dual;
TO_CHAR(35*8*1024,'XXXX
-----------------------
                  46000
SQL> select to_char(36*8*1024,'xxxxxxxxxxxxxxxxxxxxxx') from dual;
TO_CHAR(36*8*1024,'XXXX
-----------------------
                  48000
我們使用UE修改46000H到48000H之間的資料。
啟動資料庫，查詢：
SQL> select count(*) from tab_dbv;
select count(*) from tab_dbv
                     *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 6, block # 560)
ORA-01110: data file 6: 'E:\ORACLE\PRODUCT\10.2.0\ORADATA\HUNT\GHOST_001.DBF'
使用DBV對資料檔案進行檢查：
C:\>dbv file='E:\oracle\product\10.2.0\oradata\hunt\GHOST_001.DBF'
......
Page 560 is marked corrupt
Corrupt block relative dba: 0x01800230 (file 6, block 560)  ---第一個壞塊位置
……
Page 576 is marked corrupt
Corrupt block relative dba: 0x01800240 (file 6, block 576)  ---第二個壞塊位置
DBVERIFY - Verification complete
Total Pages Examined         : 14080
Total Pages Processed (Data) : 2782
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 88
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 80
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 11128
Total Pages Marked Corrupt   : 2               -----有兩個塊損壞。
Total Pages Influx           : 0
Highest block SCN            : 1255980 (0.1255980)
2、檢查壞塊：
RMAN> backup validate database;
SQL>select * from v$database_block_corruption;
  
FILE#
BLOCK#
BLOCKS
CORRUPTION_CHANGE#
CORRUPTION_TYPE
1
6
576
1
0
CORRUPT
2
6
560
1
0
CORRUPT
與DBV報出的結果一致。
3、修復壞塊：
RMAN> blockrecover datafile 6 block 560;
---此命令是10G才有的，9I不支援。
RMAN> backup validate datafile 6;
---重新檢驗。
SQL>select * from v$database_block_corruption;
  
FILE#
BLOCK#
BLOCKS
CORRUPTION_CHANGE#
CORRUPTION_TYPE
1
6
576
1
0
CORRUPT
SQL> select count(*) from tab_dbv;
select count(*) from tab_dbv
                     *
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 6, block # 576) 
---此時報576損壞，說明560已修復
ORA-01110: data file 6: 'E:\ORACLE\PRODUCT\10.2.0\ORADATA\HUNT\GHOST_001.DBF'
說明：
存在壞塊時RMAN備份無法進行，如：
RMAN> backup datafile 6;
Starting backup at 26-MAY-12
using channel ORA_DISK_1
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00006 name=E:\ORACLE\PRODUCT\10.2.0\ORADATA\HUNT\GHOST_001.DBF
channel ORA_DISK_1: starting piece 1 at 26-MAY-12
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of backup command on ORA_DISK_1 channel at 05/26/2012 08:54:40
ORA-19566: exceeded limit of 0 corrupt blocks for file E:\ORACLE\PRODUCT\10.2.0\ORADATA\HUNT\GHOST_001.DBF
我們可以修改corrupt的允許數量（預設為0）對資料檔案進行備份。在執行RUN指令碼時指定maxcorrupt即可：
RUN {
Set maxcorrupt for datafile 6 to 1;
Backup datafile 6;
…..
}
在命令列方式下執行會報錯：
RMAN> Set maxcorrupt for datafile 6 to 1;
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03031: this option of set command needs to be used inside a run block
按同樣方法修復(file # 6, block # 576)：
RMAN> blockrecover datafile 6 block 576;
RMAN> backup validate datafile 6;
SQL>select * from v$database_block_corruption;
no rows selected
查詢資料：
SQL> select count(*) from tab_dbv;
  COUNT(*)
----------
201452
修復成功！

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