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：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！
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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
total 14300
-rw-r----- 1 oracle oinstall 4492 Jul 15 11:34 prod_ora_2883.trc
-rw-r----- 1 oracle oinstall 69 Jul 15 11:34 prod_ora_2883.trm
-rw-r----- 1 oracle oinstall 557756 Jul 15 10:17 alert_prod.log
-rw-r----- 1 oracle oinstall 947 Jul 15 10:17 prod_ckpt_2541.trc
-rw-r----- 1 oracle oinstall 59 Jul 15 10:17 prod_ckpt_2541.trm
-rw-r----- 1 oracle oinstall 1783 Jul 15 10:12 prod_j000_2588.trc
-rw-r----- 1 oracle oinstall 80 Jul 15 10:12 prod_j000_2588.trm
查看转储文件：
[oracle@rh6 ~]$ cat /u01/app/oracle/diag/rdbms/prod/prod/trace/prod_ora_2883.trc|more
Trace file /u01/app/oracle/diag/rdbms/prod/prod/trace/prod_ora_2883.trc
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1
System name: Linux
Node name: rh6
Release: 2.6.32-358.el6.x86_64
Version: #1 SMP Tue Jan 29 11:47:41 EST 2013
Machine: x86_64
Instance name: prod
Redo thread mounted by this instance: 1
Oracle process number: 26
Unix process pid: 2883, image: oracle@rh6 (TNS V1-V3)
*** 2014-07-15 11:34:50.092
*** SESSION ID:(37.32) 2014-07-15 11:34:50.092
*** CLIENT ID:() 2014-07-15 11:34:50.092
*** SERVICE NAME:(SYS$USERS) 2014-07-15 11:34:50.092
*** MODULE NAME:(sqlplus@rh6 (TNS V1-V3)) 2014-07-15 11:34:50.092
*** ACTION NAME:() 2014-07-15 11:34:50.092
Start dump data blocks tsn: 4 file#:4 minblk 170 maxblk 170
Block dump from cache:
Dump of buffer cache at level 4 for tsn=4, rdba=16777386
Block dump from disk:
buffer tsn: 4 rdba: 0x010000aa (4/170)
scn: 0x0000.001f891c seq: 0x02 flg: 0x04 tail: 0x891c2302
frmt: 0x02 chkval: 0x8eee type: 0x23=PAGETABLE SEGMENT HEADER
Hex dump of block: st=0, typ_found=1
Dump of memory from 0x00007F7DFC5C7A00 to 0x00007F7DFC5C9A00
7F7DFC5C7A00 0000A223 010000AA 001F891C 04020000 [#...............]
---此行内容与Uedit32打开内容一致
7F7DFC5C7A10 00008EEE 00000000 00000000 00000000 [................]
7F7DFC5C7A20 00000000 00000001 00000008 00000A9C [................]
7F7DFC5C7A30 00000000 00000008 00000008 010000B0 [................]
7F7DFC5C7A40 00000000 00000000 00000000 00000008 [................]
7F7DFC5C7A50 00000000 00000000 00000000 00000000 [................]
7F7DFC5C7A60 00000008 00000008 010000B0 00000000 [................]
7F7DFC5C7A70 00000000 00000000 00000008 010000A8 [................]
7F7DFC5C7A80 010000A8 00000000 00000000 00000000 [................]
7F7DFC5C7A90 00000000 00000000 00000000 00000000 [................]
Repeat 3 times
7F7DFC5C7AD0 00000001 00002000 00000000 00001434 [..... ......4...]
7F7DFC5C7AE0 00000000 010000A9 00000001 010000A8 [................]
7F7DFC5C7AF0 010000A9 00000000 00000000 00000000 [................]
7F7DFC5C7B00 00000000 00000000 00000001 00000000 [................]
7F7DFC5C7B10 0001257B 10000000 010000A8 00000008 [{%..............]
7F7DFC5C7B20 00000000 00000000 00000000 00000000 [................]
Repeat 152 times
7F7DFC5C84B0 010000A8 010000AB 00000000 00000000 [................]
7F7DFC5C84C0 00000000 00000000 00000000 00000000 [................]
Repeat 151 times
7F7DFC5C8E40 00000000 00000000 010000A9 00000000 [................]
7F7DFC5C8E50 00000000 00000000 00000000 00000000 [................]
Repeat 185 times
7F7DFC5C99F0 00000000 00000000 00000000 891C2302 [.............#..]
Extent Control Header
-----------------------------------------------------------------
Extent Header:: spare1: 0 spare2: 0 #extents: 1 #blocks: 8
last map 0x00000000 #maps: 0 offset: 2716
Highwater:: 0x010000b0 ext#: 0 blk#: 8 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 8
mapblk 0x00000000 offset: 0
Unlocked
--------------------------------------------------------
Low HighWater Mark :
Highwater:: 0x010000b0 ext#: 0 blk#: 8 ext size: 8
#blocks in seg. hdr's freelists: 0
#blocks below: 8
mapblk 0x00000000 offset: 0
Level 1 BMB for High HWM block: 0x010000a8
Level 1 BMB for Low HWM block: 0x010000a8
--------------------------------------------------------
Segment Type: 1 nl2: 1 blksz: 8192 fbsz: 0
L2 Array start offset: 0x00001434
First Level 3 BMB: 0x00000000
L2 Hint for inserts: 0x010000a9
Last Level 1 BMB: 0x010000a8
Last Level II BMB: 0x010000a9
Last Level III BMB: 0x00000000
Map Header:: next 0x00000000 #extents: 1 obj#: 75131 flag: 0x10000000
Inc # 0
Extent Map
-----------------------------------------------------------------
0x010000a8 length: 8
Auxillary Map
--------------------------------------------------------
Extent 0 : L1 dba: 0x010000a8 Data dba: 0x010000ab
--------------------------------------------------------
Second Level Bitmap block DBAs
--------------------------------------------------------
DBA 1: 0x010000a9
End dump data blocks tsn: 4 file#: 4 minblk 170 maxblk 170
2、将Uedit32（通过16进制编辑功能）编辑过的数据文件上传到数据库
13:59:58 SYS@ prod>alter system flush buffer_cache;
System altered.
读取数据出错：
14:00:05 SYS@ prod>select * from scott.emp1;
select * from scott.emp1
*
ERROR at line 1:
ORA-01578: ORACLE data block corrupted (file # 4, block # 170)
ORA-01110: data file 4: '/u01/app/oracle/oradata/prod/users01.dbf'
验证数据文件：
[oracle@rh6 ~]$ dbv file=/u01/app/oracle/oradata/prod/users01.dbf blocksize=8192
DBVERIFY: Release 11.2.0.1.0 - Production on Tue Jul 15 13:59:41 2014
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
DBVERIFY - Verification starting : FILE = /u01/app/oracle/oradata/prod/users01.dbf
Page 170 is marked corrupt
Corrupt block relative dba: 0x010000aa (file 4, block 170)
Bad check value found during dbv:
Data in bad block:
type: 35 format: 2 rdba: 0x010000aa
last change scn: 0x0000.001f891c seq: 0x2 flg: 0x04
spare1: 0x0 spare2: 0x0 spare3: 0x0
consistency value in tail: 0x891c2302
check value in block header: 0x8eee
computed block checksum: 0x2020
Page 171 is marked corrupt
Corrupt block relative dba: 0x010000ab (file 4, block 171)
Bad header found during dbv:
Data in bad block:
type: 6 format: 2 rdba: 0x012020ab
last change scn: 0x2020.201f890b seq: 0x2 flg: 0x04
spare1: 0x20 spare2: 0x20 spare3: 0x2020
consistency value in tail: 0x890b0602
check value in block header: 0xcf8b
computed block checksum: 0x2e00
Page 172 is marked corrupt
Corrupt block relative dba: 0x010000ac (file 4, block 172)
Bad header found during dbv:
Data in bad block:
type: 6 format: 2 rdba: 0x012020ac
last change scn: 0x2020.201f891c seq: 0x3 flg: 0x06
spare1: 0x20 spare2: 0x20 spare3: 0x2020
consistency value in tail: 0x891c0603
check value in block header: 0xa5b1
computed block checksum: 0x0
Page 173 is marked corrupt
Corrupt block relative dba: 0x010000ad (file 4, block 173)
Bad header found during dbv:
Data in bad block:
type: 6 format: 2 rdba: 0x012020ad
last change scn: 0x2020.201f891c seq: 0x1 flg: 0x04
spare1: 0x20 spare2: 0x20 spare3: 0x2020
consistency value in tail: 0x891c0601
check value in block header: 0xf6ab
computed block checksum: 0x2020
Page 174 is marked corrupt
Corrupt block relative dba: 0x010000ae (file 4, block 174)
Bad header found during dbv:
Data in bad block:
type: 6 format: 2 rdba: 0x012020ae
last change scn: 0x2020.201f891c seq: 0x1 flg: 0x04
spare1: 0x20 spare2: 0x20 spare3: 0x2020
consistency value in tail: 0x891c0601
check value in block header: 0xcef0
computed block checksum: 0x20
Page 175 is marked corrupt
Corrupt block relative dba: 0x010000af (file 4, block 175)
Bad header found during dbv:
Data in bad block:
type: 6 format: 2 rdba: 0x012020af
last change scn: 0x2020.201f891c seq: 0x1 flg: 0x04
spare1: 0x20 spare2: 0x20 spare3: 0x2020
consistency value in tail: 0x891c0601
check value in block header: 0x146a
computed block checksum: 0x0
Page 176 is marked corrupt
Corrupt block relative dba: 0x010000b0 (file 4, block 176)
Bad header found during dbv:
Data in bad block:
type: 6 format: 2 rdba: 0x012020b0
last change scn: 0x2020.201e6219 seq: 0x1 flg: 0x04
spare1: 0x20 spare2: 0x20 spare3: 0x2020
consistency value in tail: 0x62190601
check value in block header: 0x2185
computed block checksum: 0x2020
DBVERIFY - Verification complete
Total Pages Examined : 12800
Total Pages Processed (Data) : 757
Total Pages Failing (Data) : 0
Total Pages Processed (Index): 2
Total Pages Failing (Index): 0
Total Pages Processed (Other): 12024
Total Pages Processed (Seg) : 0
Total Pages Failing (Seg) : 0
Total Pages Empty : 10
Total Pages Marked Corrupt : 7
Total Pages Influx : 0
Total Pages Encrypted : 0
Highest block SCN : 2066716 (0.2066716)
从以上验证结果看：总共有7个数据块（170-176）被破坏！
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