11g DataGuard通過ABMR自動修復主庫壞塊 - Automatic Block Media Repair

tolywang發表於2014-01-21
BloCAI

 在11g Active DataGuard中,如果我們使用real time的功能,我們就可以使用Automatic Block Media Repair的特性來修復主庫的壞塊. 因為當你使用了real time的功能後,你對主庫的更新會迅速傳到備庫,此時主庫出現壞塊,我們可以相反的從備庫上把已經applying的block在傳回給主庫。

1、open real time Feature
alter database recover managed standby database cancel;
alter database open read only;
alter database recover managed standby database using current logfile disconnect;
 
2、Identify the blocks allocated to a table that contains containing data.

You may use the following query to translate the rowid to a file# and block#

select rowid, dbms_rowid.rowid_block_number(rowid) blockno, dbms_rowid.rowid_relative_fno(rowid) fno
from test.test  where rownum < 100

3. Using the block from the datafile identified file# using DD utility at OS level.

dd if=/dev/zero f=/oradata/orcl/users.dbf count=1 seek=164 bs=8192 conv=notrunc

4. Check the datafile for corruption :

dbv file=/oradata/orcl/users.dbf blocksize=8192

5. Flush the buffer cache on primary database to force a re-read the data from disk

alter system flush buffer_cache;

6. Attempt to select from the table. No error should occur and the data should return as valid
select * from test.test where dbms_rowid.rowid_block_number(rowid)=164  
and dbms_rowid.rowid_relative_fno(rowid)=9


此時我們可以看到資料能夠查詢出來,那麼看一下我們的後臺alert日誌,記錄了下列內容：
  
ALTER SYSTEM: Flushing buffer cache
Wed Jul 07 17:35:09 2012
Hex dump of (file 9, block 164) in trace file /oracle/app/oracle/diag/rdbms/dg1/dg1/trace/dg1_ora_4391.trc
Corrupt block relative dba: 0x010000ab (file 9, block 164)
Completely zero block found during multiblock buffer read
Reading datafile '/oradata/orcl/users.dbf ' for corruption at rdba: 0x010000ab (file 9, block 164)
Reread (file 9, block 164) found same corrupt data
Starting background process ABMR
Wed Jul 07 17:35:09 2012
ABMR started with pid=55, OS id=4364
Auto BMR service is active.
Requesting Auto BMR for (file 9, block 164)
Waiting Auto BMR response for (file 9, block 164)
Auto BMR successful 
轉自： http://blog.csdn.net/linghao00/article/details/7944706 

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