Oracle数据库坏块修复方法
BBED是Block Browser/Editor的缩写，是Oracle的一个内部工具，不对外发布文档及支持。 BBED随软件发布，但是我们需要进行简单的relink才能使用。
虽然BBED工具的使用存在很多风险，但是如果利用得当，可以以之解决很多棘手的问题，并且可以练习坏块修复等技术。
例如在Oracle10g中的bbed工具，同样需要我们手工relink才能使用，这个版本的工具同样可以在其他版本的数据库中使用:
[oracle@danaly lib]$ make -f ins_rdbms.mk $ORACLE_HOME/rdbms/lib/bbed
Linking BBED utility (bbed)
rm -f /opt/oracle/product/10.2.0/rdbms/lib/bbed
gcc -o /opt/oracle/product/10.2.0/rdbms/lib/bbed ...
-L/opt/oracle/product/10.2.0/lib
[oracle@danaly lib]$ bbed
Password:
BBED: Release 2.0.0.0.0 - Limited Production on Sun Sep 3 12:42:59 2006
Copyright (c) 1982, 2005, Oracle. All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************
BBED> help ALL
SET DBA [ dba | file#, block# ]
SET FILENAME 'filename'
SET FILE file#
SET BLOCK [+/-]block#
SET OFFSET [ [+/-]byte offset | symbol | *symbol ]
SET BLOCKSIZE bytes
SET LIST[FILE] 'filename'
SET WIDTH character_count
SET COUNT bytes_to_display
SET IBASE [ HEX | OCT | DEC ]
SET OBASE [ HEX | OCT | DEC ]
SET MODE [ BROWSE | EDIT ]
SET SPOOL [ Y | N ]
SHOW [ | ALL ]
POP [ALL]
REVERT [ DBA | FILE | FILENAME | BLOCK ]
UNDO
HELP [ | ALL ]
VERIFY [ DBA | FILE | FILENAME | BLOCK ]
CORRUPT [ DBA | FILE | FILENAME | BLOCK ]
Oracle Database 11g中缺省的未提供BBED库文件，但是可以用10g的文件编译出来，参考如下步骤：
1.复制Oracle 10g文件
Copy $ORA10g_HOME/rdbms/lib/ssbbded.o to $ORA11g_HOME/rdbms/lib
Copy $ORA10g_HOME/rdbms/lib/sbbdpt.o to $ORA11g_HOME/rdbms/lib
Copy $ORA10g_HOME/rdbms/mesg/bbedus.msb to $ORA11g_HOME/rdbms/mesg
Copy $ORA10g_HOME/rdbms/mesg/bbedus.msg to $ORA11g_HOME/rdbms/mesg
Copy $ORA10g_HOME/rdbms/mesg/bbedar.msb to $ORA11g_HOME/rdbms/mesg
2.编译
make -f $ORA11g_HOME/rdbms/lib/ins_rdbms.mk BBED=$ORACLE_HOME/bin/bbed $ORACLE_HOME/bin/bbed
BBED的缺省口令为blockedit,请谨慎使用,内部工具。Oracle不做技术支持。
我前面提到，可以通过这个工具模拟坏块，以便进行坏块相关的学习和研究，以下是一个示例.
1.备份数据文件
本测试中恢复损坏的文件，需要存在一个良好文件，本文简单冷备份一下文件.
[oracle@jumper conner]$ cp users01.dbf users01.dbf.bak
2.修改BBED参数文件
加入备份文件
[oracle@jumper conner]$ vi filelist.txt
1 /opt/oracle/oradata/conner/system01.dbf 440401920
2 /opt/oracle/oradata/conner/undotbs01.dbf 104857600
3 /opt/oracle/oradata/conner/users01.dbf 27262976
4 /opt/oracle/oradata/conner/users01.dbf.bak 27262976
~
~
~
"filelist.txt" 4L, 259C written
[oracle@jumper conner]$ more par.bbd
blocksize=8192
listfile=filelist.txt
mode=edit
3.破坏数据块
[oracle@jumper conner]$ bbed parfile=par.bbd
Password:
BBED: Release 2.0.0.0.0 - Limited Production on Sun Sep 11 22:30:11 2005
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************
BBED> set file 3
FILE# 3
BBED> modify 1000 file 3 block 17
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) Y
File: /opt/oracle/oradata/conner/users01.dbf (3)
Block: 17 Offsets: 0 to 511 Dba:0x00c00011
------------------------------------------------------------------------
03e80000 1100c000 75b5a320 00000104 06300000 01000000 611e0000 72b5a320
00000000 03003201 0900c000 ffff0000 00000000 00000000 00000000 00800000
72b5a320 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00012600
ffff5e00 d5037703 77030000 2600c21e 101e581d a91cf61b 471b941a dd192819
6218b417 06175216 9715dd14 26146c13 b4120712 44118310 bc0ffa0e 380e790d
b60cf40b 350b790a c0090409 45088b07 cc060e06 57059804 d5030000 00000000
BBED> verify
DBVERIFY - Verification starting
FILE = /opt/oracle/oradata/conner/users01.dbf
BLOCK = 17
Block 17 is corrupt
***
Corrupt block relative dba: 0x00c00011 (file 0, block 17)
Bad header found during verification
Data in bad block -
type: 3 format: 0 rdba: 0x00c00011
last change scn: 0x0000.20a3b575 seq: 0x1 flg: 0x04
consistency value in tail: 0xb5750601
check value in block header: 0x3006, computed block checksum: 0xea05
spare1: 0x0, spare2: 0x0, spare3: 0x0
***
BBED> quit
4.从备份文件中copy良好数据块进行恢复
[oracle@jumper conner]$ bbed parfile=par.bbd
Password:
BBED: Release 2.0.0.0.0 - Limited Production on Sun Sep 11 22:33:55 2005
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
************* !!! For Oracle Internal Use only !!! ***************
BBED> set file 4
FILE# 4
BBED> show
FILE# 4
BLOCK# 1
OFFSET 0
DBA 0x01000001 (16777217 4,1)
FILENAME /opt/oracle/oradata/conner/users01.dbf.bak
BIFILE bifile.bbd
LISTFILE filelist.txt
BLOCKSIZE 8192
MODE Edit
EDIT Unrecoverable
IBASE Dec
OBASE Dec
WIDTH 80
COUNT 512
LOGFILE log.bbd
SPOOL No
BBED> copy file 4 block 17 to file 3 block 17;
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) Y
File: /opt/oracle/oradata/conner/users01.dbf (3)
Block: 17 Offsets: 0 to 511 Dba:0x00c00011
------------------------------------------------------------------------
06020000 1100c000 75b5a320 00000104 06300000 01000000 611e0000 72b5a320
00000000 03003201 0900c000 ffff0000 00000000 00000000 00000000 00800000
72b5a320 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00012600
ffff5e00 d5037703 77030000 2600c21e 101e581d a91cf61b 471b941a dd192819
6218b417 06175216 9715dd14 26146c13 b4120712 44118310 bc0ffa0e 380e790d
b60cf40b 350b790a c0090409 45088b07 cc060e06 57059804 d5030000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BBED> verify
DBVERIFY - Verification starting
FILE = /opt/oracle/oradata/conner/users01.dbf
BLOCK = 17
DBVERIFY - Verification complete
Total Blocks Examined : 1
Total Blocks Processed (Data) : 1
Total Blocks Failing (Data) : 0
Total Blocks Processed (Index): 0
Total Blocks Failing (Index): 0
Total Blocks Empty : 0
Total Blocks Marked Corrupt : 0
Total Blocks Influx : 0
这样就通过一个完好文件的完好数据块复制，完成了简单的复制恢复。
5.数据库验证
原文链接里包含详细的表创建和其他步骤，供参考。
SQL> select count(*) from bbed;
select count(*) from bbed
*
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 3, block # 17)
ORA-01110: data file 3: '/opt/oracle/oradata/conner/users01.dbf'
SQL> alter tablespace users offline;
Tablespace altered.
SQL> alter tablespace users online;
Tablespace altered.
SQL> select count(*) from bbed;
COUNT(*)
----------
523
善用BBED可以从很多棘手的问题中拯救我们的数据库，作为Oracle DBA需要了解这样一个工具的存在。
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