oracle恢复指定数据文件,Oracle特殊恢复-BBED修改某个数据文件头

Oracle数据文件头中的scn要与控制文件中的scn一致，数据库才可以open，在open过程中我们可以通过bbed来修改某个数据文件头的scn，来欺骗oracle，来open库。

1、环境如下

使用Oracle 11gR2进行测试，具体版本为11.2.0.4

SYS@linuxidc SQL>select file#,name,checkpoint_change#,checkpoint_time from v$datafile;

FILE# NAME CHECKPOINT_CHANGE# CHECKPOINT_TIME

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

1 /dbdata/oradata/linuxidc/system01.dbf 1233066 2016-11-10 11:23:44

2 /dbdata/oradata/linuxidc/sysaux01.dbf 1233066 2016-11-10 11:23:44

3 /dbdata/oradata/linuxidc/undotbs01.dbf 1233066 2016-11-10 11:23:44

4 /dbdata/oradata/linuxidc/users01.dbf 1233066 2016-11-10 11:23:44

5 /dbdata/oradata/linuxidc/moe01.dbf 1233066 2016-11-10 11:23:44

2、模拟某个数据文件在问题

shutdown immediate数据库，然后拷贝moe01.dbf这个数据文件，然后打开数据库，做日志切换，然后shutdown immediate，再把之前的拷贝替换现在的moe01.dbf数据文件

SYS@linuxidc SQL>shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

[oracle@tstdb-25-220 linuxidc]$ cp moe01.dbf moe01.dbf.bak

[oracle@tstdb-25-220 linuxidc]$ ll

总用量 3872076

-rw-r-----. 1 oracle oinstall 9748480 11月 10 09:48 control01.ctl

-rw-r-----. 1 oracle oinstall 9748480 11月 10 09:48 control02.ctl

-rw-r-----. 1 oracle oinstall 1073750016 11月 10 09:48 moe01.dbf

-rw-r-----. 1 oracle oinstall 1073750016 11月 10 11:23 moe01.dbf.bak

-rw-r-----. 1 oracle oinstall 52429312 11月 9 13:13 redo01.log

-rw-r-----. 1 oracle oinstall 52429312 11月 9 22:00 redo02.log

-rw-r-----. 1 oracle oinstall 52429312 11月 10 09:48 redo03.log

-rw-r-----. 1 oracle oinstall 587210752 11月 10 09:48 sysaux01.dbf

-rw-r-----. 1 oracle oinstall 807411712 11月 10 09:48 system01.dbf

-rw-r-----. 1 oracle oinstall 30416896 11月 9 22:00 temp01.dbf

-rw-r-----. 1 oracle oinstall 131080192 11月 10 09:48 undotbs01.dbf

-rw-r-----. 1 oracle oinstall 111419392 11月 10 09:48 users01.dbf

SYS@linuxidc SQL>startup

ORACLE instance started.

Total System Global Area 2455228416 bytes

Fixed Size 2255712 bytes

Variable Size 620758176 bytes

Database Buffers 1811939328 bytes

Redo Buffers 20275200 bytes

Database mounted.

Database opened.

SYS@linuxidc SQL>alter system switch logfile;

System altered.

SYS@linuxidc SQL>alter system switch logfile;

System altered.

SYS@linuxidc SQL>alter system switch logfile;

System altered.

SYS@linuxidc SQL>shutdown immediate

Database closed.

Database dismounted.

ORACLE instance shut down.

[oracle@tstdb-25-220 linuxidc]$ cp moe01.dbf moe01.dbf.bak.f

[oracle@tstdb-25-220 linuxidc]$ cp moe01.dbf.bak moe01.dbf

启动数据库报错

SYS@linuxidc SQL>startup

ORACLE instance started.

Total System Global Area 2455228416 bytes

Fixed Size 2255712 bytes

Variable Size 620758176 bytes

Database Buffers 1811939328 bytes

Redo Buffers 20275200 bytes

Database mounted.

ORA-01113: file 5 needs media recovery

ORA-01110: data file 5: '/dbdata/oradata/linuxidc/moe01.dbf'

SYS@linuxidc SQL>recover datafile 5;

ORA-00279: change 1233063 generated at 11/10/2016 09:48:02 needed for thread 1

ORA-00289: suggestion : /apps/oracle/11.2.0/db_1/dbs/arch1_24_925478204.dbf

ORA-00280: change 1233063 for thread 1 is in sequence #24

Specify log: {=suggested | filename | AUTO | CANCEL}

auto

ORA-00308: cannot open archived log '/apps/oracle/11.2.0/db_1/dbs/arch1_24_925478204.dbf'

ORA-27037: unable to obtain file status

Linux-x86_64 Error: 2: No such file or directory

Additional information: 3

ORA-00308: cannot open archived log '/apps/oracle/11.2.0/db_1/dbs/arch1_24_925478204.dbf'

ORA-27037: unable to obtain file status

Linux-x86_64 Error: 2: No such file or directory

Additional information: 3

3、场景模拟出来了，下面是修复过程

使用BBED，将文件头的SCN等关键信息修改到与控制文件control file相匹配即可

SYS@linuxidc SQL>select file#, CHECKPOINT_CHANGE# from v$datafile;

FILE# CHECKPOINT_CHANGE#

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

1 1233692

2 1233692

3 1233692

4 1233692

5 1233692

SYS@linuxidc SQL>select CHECKPOINT_CHANGE# from v$database;

CHECKPOINT_CHANGE#

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

1233692

SYS@linuxidc SQL>select file#, recover, fuzzy, CHECKPOINT_CHANGE# from v$datafile_header;

FILE# REC FUZ CHECKPOINT_CHANGE#

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

1 NO NO 1233692

2 NO NO 1233692

3 NO NO 1233692

4 NO NO 1233692

5 YES NO 1233063

控制文件中datafile5的scn是：1233692，而数据文件头中的scn是：1233063

使用bbed将datafile5的数据文件头对应的SCN修改为与其他文件相同，我们先看一下users01.dbf这个文件的文件头

BBED> set filename '/dbdata/oradata/linuxidc/users01.dbf'

FILENAME /dbdata/oradata/linuxidc/users01.dbf

BBED> set block 1

BLOCK# 1

BBED> map

File: /dbdata/oradata/linuxidc/users01.dbf (0)

Block: 1 Dba:0x00000000

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

Data File Header

struct kcvfh, 860 bytes @0

ub4 tailchk @8188

因为我们要修改数据文件头，因此我们需要关注四个偏移量offset点，分别为484、492、140和148

1、datafile 的file header 存储在第一个block里

2、Oracle considers four attributes of this data structure when determining if a datafile is sync with the other data files of the database:(不同oracle版本offset可能不同)

(1)kscnbas (at offset 484) – SCN of last change to the datafile.

(2)kcvcptim (at offset 492) -Time of the last change to the datafile.

(3)kcvfhcpc (at offset 140) – Checkpoint count.

(4)kcvfhccc (at offset 148) – Unknown, but is always 1 less than thecheckpoint point count.

Oracle有4个属性来判断datafile 是否和其他的datafile 一致，如果都一致，可以正常操作，如果不一致，那么会报ORA-01113错误

下面我们看下这几个offset

BBED> set offset 484

OFFSET 484

BBED> dump

File: /dbdata/oradata/linuxidc/users01.dbf (0)

Block: 1 Offsets: 484 to 995 Dba:0x00000000

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

1cd31200 00000000 bd384937 01000000 1b000000 30010000 100051f2 02000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

0d000d00 0d000100 00000000 00000000 00000000 02000001 03000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

<32 bytes per line>

BBED> set offset 492

OFFSET 492

BBED> dump

File: /dbdata/oradata/linuxidc/users01.dbf (0)

Block: 1 Offsets: 492 to 1003 Dba:0x00000000

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

bd384937 01000000 1b000000 30010000 100051f2 02000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 0d000d00 0d000100

00000000 00000000 00000000 02000001 03000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

<32 bytes per line>

BBED> set offset 140

OFFSET 140

BBED> dump

File: /dbdata/oradata/linuxidc/users01.dbf (0)

Block: 1 Offsets: 140 to 651 Dba:0x00000000

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

78000000 14ff4737 77000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

04000000 05005553 45525300 00000000 00000000 00000000 00000000 00000000

00000000 04000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 7ac92131 01000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 1cd31200 00000000

bd384937 01000000 1b000000 30010000 100051f2 02000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 0d000d00 0d000100

<32 bytes per line>

BBED> set offset 148

OFFSET 148

BBED> dump

File: /dbdata/oradata/linuxidc/users01.dbf (0)

Block: 1 Offsets: 148 to 659 Dba:0x00000000

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

77000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 04000000 05005553

45525300 00000000 00000000 00000000 00000000 00000000 00000000 04000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 7ac92131 01000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 1cd31200 00000000 bd384937 01000000

1b000000 30010000 100051f2 02000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 0d000d00 0d000100 00000000 00000000

<32 bytes per line>

其中，位于484和488偏移量的是数据文件对应的SCN编号。在Oracle内部，SCN是使用wrap*4*1024*1024*1024+base来进行标示的。通常我们看到的数据库wrap都是0。位于492偏移量的是最后一次检查点对应的时间信息。位于140和148偏移量的是检查点次数。这些信息都是会由于时间推动和检查点动作引起变化，我们严格情况下，需要保证文件头块的信息和控制文件信息一致。

另外一点，由于Linux是Little字节系统，要关注写入时候的格式问题。最简单的方式是dump一下偏移量，看看是怎么保存的。

1234567 BBED> dump

File: /dbdata/oradata/linuxidc/users01.dbf (0)

Block: 1 Offsets: 484 to 995 Dba:0x00000000

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

1cd31200 00000000 bd384937 01000000 1b000000 30010000 100051f2 02000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

然后我们修改moe01.dbf的文件头(修改这几个offset，我这里只修改了484、492就可以open库了)

BBED> set filename '/dbdata/oradata/linuxidc/moe01.dbf'

FILENAME /dbdata/oradata/linuxidc/moe01.dbf

BBED> set block 1

BLOCK# 1

BBED> set mode edit

MODE Edit

BBED> set offset 484

OFFSET 484

BBED> dump

File: /dbdata/oradata/linuxidc/moe01.dbf (0)

Block: 1 Offsets: 484 to 995 Dba:0x00000000

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

a7d01200 00000000 52204937 01000000 18000000 4d8d0000 100051f2 02000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

0d000d00 0d000100 00000000 00000000 00000000 02004001 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

<32 bytes per line>

BBED> m /x 1cd31200 484

Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y

File: /dbdata/oradata/linuxidc/moe01.dbf (0)

Block: 1 Offsets: 484 to 995 Dba:0x00000000

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

1cd31200 00000000 52204937 01000000 18000000 4d8d0000 100051f2 02000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

0d000d00 0d000100 00000000 00000000 00000000 02004001 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

<32 bytes per line>

BBED> m /x bd384937 492

BBED-00209: invalid number (bd384937)

BBED> m /x bd38 492

File: /dbdata/oradata/linuxidc/moe01.dbf (0)

Block: 1 Offsets: 492 to 1003 Dba:0x00000000

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

bd384937 01000000 18000000 4d8d0000 100051f2 02000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 0d000d00 0d000100

00000000 00000000 00000000 02004001 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

<32 bytes per line>

BBED> m /x 4937 494

File: /dbdata/oradata/linuxidc/moe01.dbf (0)

Block: 1 Offsets: 494 to 1005 Dba:0x00000000

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

49370100 00001800 00004d8d 00001000 51f20200 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000d00 0d000d00 01000000

00000000 00000000 00000200 40010000 00000000 00000000 00000000 00000000

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

<32 bytes per line>

BBED> sum apply

Check value for File 0, Block 1:

current = 0x1683, required = 0x1683

BBED> verify

DBVERIFY - Verification starting

FILE = /dbdata/oradata/linuxidc/moe01.dbf

BLOCK = 1

DBVERIFY - Verification complete

Total Blocks Examined : 1

Total Blocks Processed (Data) : 0

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

Message 531 not found; product=RDBMS; facility=BBED

这时我们再次查看各个数据文件头的scn，发现scn一致了

123456789 SYS@linuxidc SQL>select file#, recover, fuzzy, CHECKPOINT_CHANGE# from v$datafile_header;

FILE# REC FUZ CHECKPOINT_CHANGE#

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

1 NO NO 1233692

2 NO NO 1233692

3 NO NO 1233692

4 NO NO 1233692

5 YES NO 1233692

试着open库

SYS@linuxidc SQL>alter database open

2 ;

alter database open

ERROR at line 1:

ORA-01113: file 5 needs media recovery

ORA-01110: data file 5: '/dbdata/oradata/linuxidc/moe01.dbf'

SYS@linuxidc SQL>recover datafile 5;

Media recovery complete.

SYS@linuxidc SQL>alter database open;

Database altered.

看一下alert文件

ALTER DATABASE RECOVER datafile 5

Media Recovery Start

Serial Media Recovery started

Media Recovery Complete (linuxidc)

Completed: ALTER DATABASE RECOVER datafile 5

Thu Nov 10 13:47:24 2016

alter database open

Thu Nov 10 13:47:25 2016

Thread 1 opened at log sequence 27

Current log# 3 seq# 27 mem# 0: /dbdata/oradata/linuxidc/redo03.log

Successful open of redo thread 1

MTTR advisory is disabled because FAST_START_MTTR_TARGET is not set

Thu Nov 10 13:47:25 2016

SMON: enabling cache recovery

[20910] Successfully onlined Undo Tablespace 2.

Undo initialization finished serial:0 start:3710149144 end:3710149224 diff:80 (0 seconds)

Verifying file header compatibility for 11g tablespace encryption..

Verifying 11g file header compatibility for tablespace encryption completed

SMON: enabling tx recovery

Database Characterset is AL32UTF8

No Resource Manager plan active

replication_dependency_tracking turned off (no async multimaster replication found)

Starting background process QMNC

Thu Nov 10 13:47:25 2016

QMNC started with pid=20, OS id=21409

Completed: alter database open

在本次恢复过程中，recover是可行的，原因是该库并没做过resetlog，如果datafile是在 resetlog之前就已经offline的数据文件，那recover是不可行的。

oracle恢复指定数据文件,Oracle特殊恢复-BBED修改某个数据文件头

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