Method of completely corrupting recovery of ASM disk Header in Oracle

Test preparation
Create a new table space, create a T_xifenfei test table

The code is as follows

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sql> Create tablespace Xifenfei datafile ' +xifenfei ' SIZE 50m; Tablespace created. sql> CREATE TABLE T_xifenfei tablespace Xifenfei 2 as SELECT * from Dba_objects; Table created. Sql> SELECT COUNT (*) from T_xifenfei; COUNT (*) ---------- 50031 Sql> select Ts#,rfile#,bytes/1024/1024,blocks,name from V$datafile; ts# rfile# bytes/1024/1024 BLOCKS NAME ---------- ---------- --------------- ---------- -------------------------------------------------- 0 1 61440 +xifenfei/asm10g/datafile/system.256.845260203 1 2 3200 +xifenfei/asm10g/datafile/undotbs1.258.845260205 2 3 32000 +xifenfei/asm10g/datafile/sysaux.257.845260203 4 4 5 640 +xifenfei/asm10g/datafile/users.259.845260205 6 5 6400 +xifenfei/asm10g/datafile/xifenfei.266.845262139 Sql> select Group_number,disk_number,state,total_mb,free_mb,name,path from V$asm_disk; Group_number disk_number State total_mb free_mb NAME PATH ------------ ----------- -------- ---------- ---------- -------------------- ------------------ 1 0 NORMAL 2048 0 xifenfei_0000/dev/raw/raw1 1 1 NORMAL 784 0 xifenfei_0001/dev/raw/raw2 1 2 NORMAL 7059 0 xifenfei_0002/dev/raw/raw3 --Close the database sql> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. --Close ASM sql> shutdown Immediate ASM diskgroups dismounted ASM instance shutdown

View the disk for the bare device

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[Oracle@xifenfei dul]$ More/etc/sysconfig/rawdevices /dev/raw/raw1/dev/sdc /dev/raw/raw2/dev/sdd1 /dev/raw/raw3/dev/sdd2

DD Disk Header

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DD ASM Disk Front 10M, completely destroy ASM disk [Oracle@xifenfei ~]$ dd if=/dev/zero of=/dev/raw/raw1 bs=1m count=10 conv=notrunc 10+0 Records in 10+0 Records out 10485760 bytes (MB) copied, 0.175424 seconds, 59.8 MB/s [Oracle@xifenfei ~]$ dd if=/dev/zero of=/dev/raw/raw2 bs=1m count=10 conv=notrunc 10+0 Records in 10+0 Records out 10485760 bytes (MB) copied, 0.11584 seconds, 90.5 MB/s [Oracle@xifenfei ~]$ dd if=/dev/zero of=/dev/raw/raw3 bs=1m count=10 conv=notrunc 10+0 Records in 10+0 Records out 10485760 bytes (MB) copied, 0.353435 seconds, 29.7 MB/s

kfed View Disk
Make sure all ASM disk headers are completely corrupted

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[Oracle@xifenfei dul]$ kfed READ/DEV/RAW/RAW1 kfbh.endian:0; 0x000:0x00 kfbh.hard:0; 0x001:0x00 kfbh.type:0; 0x002:kfbtyp_invalid kfbh.datfmt:0; 0x003:0x00 kfbh.block.blk:0; 0x004:t=0 numb=0x0 kfbh.block.obj:0; 0x008:type=0x0 numb=0x0 kfbh.check:0; 0x00c:0x00000000 kfbh.fcn.base:0; 0x010:0x00000000 kfbh.fcn.wrap:0; 0x014:0x00000000 kfbh.spare1:0; 0x018:0x00000000 kfbh.spare2:0; 0x01c:0x00000000 [Oracle@xifenfei dul]$ kfed READ/DEV/RAW/RAW2 kfbh.endian:0; 0x000:0x00 kfbh.hard:0; 0x001:0x00 kfbh.type:0; 0x002:kfbtyp_invalid kfbh.datfmt:0; 0x003:0x00 kfbh.block.blk:0; 0x004:t=0 numb=0x0 kfbh.block.obj:0; 0x008:type=0x0 numb=0x0 kfbh.check:0; 0x00c:0x00000000 kfbh.fcn.base:0; 0x010:0x00000000 kfbh.fcn.wrap:0; 0x014:0x00000000 kfbh.spare1:0; 0x018:0x00000000 kfbh.spare2:0; 0x01c:0x00000000 [Oracle@xifenfei dul]$ kfed READ/DEV/RAW/RAW3 kfbh.endian:0; 0x000:0x00 kfbh.hard:0; 0x001:0x00 kfbh.type:0; 0x002:kfbtyp_invalid kfbh.datfmt:0; 0x003:0x00 kfbh.block.blk:0; 0x004:t=0 numb=0x0 kfbh.block.obj:0; 0x008:type=0x0 numb=0x0 kfbh.check:0; 0x00c:0x00000000 kfbh.fcn.base:0; 0x010:0x00000000 kfbh.fcn.wrap:0; 0x014:0x00000000 kfbh.spare1:0; 0x018:0x00000000 kfbh.spare2:0; 0x01c:0x00000000

Dul view completely corrupted ASM disk header
Test if the ASM disk header is completely corrupted, Dul is also able to implement the extract data from the ASM disks Group

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[oracle@xifenfei dul]$./dul   Data unloader:10.2.0.5.28-internal only-on Sat Apr 04:02:02 2014 with 64-bit IO fun Ctions   Copyright (c) 1994 2014 Bernard van Duijnen All rights reserved.    strictly Oracl e Internal use only     DUL:Warning:block 0 are not a disk header blocks DUL:Error:Block is no T in-use DUL:Error:Block type mismatch (seen 0 expect 1) when parsing block 0 of Disk/dev/raw/raw1   DUL:Warning:block 0 is isn't a disk header block DUL:Error:Block isn't in use DUL:Error:Block type mismatch ( Seen 0 expect 1) when parsing blocks 0 of disk/dev/raw/raw2   DUL:Warning:block 0 is not a disk header Blo CK DUL:Error:Block isn't in use DUL:Error:Block type mismatch (seen 0 expect 1) when parsing block 0 of disk /DEV/RAW/RAW3

As can be seen here, when the ASM disk header is completely abnormal, the dul is not recognized by the ASM set of disks (in which case Dul does not operate properly)

To scan a disk with a tool to extract blocks of data

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Cpfl> Scan DISK/DEV/RAW/RAW1 Scanning disk/dev/raw/raw1, at 2014-04-19 04:05:11 Completed disk/dev/raw/raw1, at 2014-04-19 04:05:56 Cpfl> Scan DISK/DEV/RAW/RAW1 Scanning disk/dev/raw/raw1, at 2014-04-19 04:05:56 Completed disk/dev/raw/raw1, at 2014-04-19 04:06:15 Cpfl> Scan DISK/DEV/RAW/RAW1 Scanning disk/dev/raw/raw1, at 2014-04-19 04:06:15 Completed disk/dev/raw/raw1, at 2014-04-19 04:07:44 Cpfl> list Datafiles Tablespace:system file:1 blocks:61440 TABLESPACE:UNDOTBS1 File:2 blocks:3200 Tablespace:sysaux File:3 blocks:32000 Tablespace:users File:4 blocks:640 Tablespace:xifenfei File:5 blocks:6400 cpfl> copy datafile 1 to/u01/oracle/oradata/asmfile/1.dbf Copy datafile start:2014-04-19 04:10:35 Copy datafile 1 have blocks 61440 Copy datafile completed:2014-04-19 04:11:18 cpfl> Copy datafile 2 to/u01/oracle/oradata/asmfile/2.dbf Copy datafile start:2014-04-19 04:11:52 Copy datafile 2 have blocks 3200 Copy datafile completed:2014-04-19 04:11:54 Cpfl> copy datafile 3 to/u01/oracle/oradata/asmfile/3.dbf Copy datafile start:2014-04-19 04:12:03 Copy datafile 3 have blocks 32000 Copy datafile completed:2014-04-19 04:12:27 cpfl> copy datafile 4 to/u01/oracle/oradata/asmfile/4.dbf Copy datafile start:2014-04-19 04:13:07 Copy datafile 4 have blocks 640 Copy datafile completed:2014-04-19 04:13:08 cpfl> copy datafile 5 to/u01/oracle/oradata/asmfile/5.dbf Copy datafile start:2014-04-19 04:13:18 Copy datafile 5 have blocks 6400 Copy datafile completed:2014-04-19 04:13:19

View using tools to extract data files

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[Oracle@xifenfei asmfile]$ Ls-l Total 830320 -rw-r--r--1 Oracle oinstall 503324672 APR 04:34 1.dbf -rw-r--r--1 Oracle oinstall 26222592 APR 04:34 2.dbf -rw-r--r--1 Oracle oinstall 262152192 APR 04:34 3.dbf -rw-r--r--1 Oracle oinstall 5251072 APR 04:34 4.dbf -rw-r--r--1 Oracle oinstall 52436992 APR 04:34 5.dbf

Dul Verification Extract File

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[Oracle@xifenfei dul]$./dul Data unloader:10.2.0.5.28-internal only-on Sat APR 19 06:56:09 2014 With 64-bit IO functions Copyright (c) 1994 2014 Bernard van Duijnen all rights reserved. Strictly Oracle Internal Use only DUL:Warning:Recreating file "Dul.log" Found db_id = 181793355 Found db_name = asm10g Dul> show Datafiles; ts# rf# Start blocks offs Open Err file name 0 1 0 61440 0 1 0/u01/oracle/oradata/asmfile/1.dbf 1 2 0 3200 0 1 0/u01/oracle/oradata/asmfile/2.dbf 2 3 0 32000 0 1 0/u01/oracle/oradata/asmfile/3.dbf 4 4 0 640 0 1 0/u01/oracle/oradata/asmfile/4.dbf 6 5 0 6400 0 1 0/u01/oracle/oradata/asmfile/5.dbf Dul> Bootstrap; Probing file = 1, block = 377 . Unloading table bootstrap$ DUL:Warning:block number is non zero but marked deferred trying to process it anyhow Rows unloaded DUL:Warning:Dictionary Cache Dc_bootstrap is empty Reading BOOTSTRAP.dat Entries Loaded Parsing bootstrap$ Contents DUL:Warning:Recreating file "Dict.ddl" Generating DICT.DDL for version 10 obj$: Segobjno, file 1 Block 121 tab$: Segobjno 2, tabno 1, file 1 Block 25 col$: Segobjno 2, tabno 5, file 1 Block 25 user$: Segobjno, tabno 1, file 1 block 89 Running generated file "@dict. DDL" to unload the dictionary tables . Unloading table obj$ 51171 rows unloaded . Unloading table tab$ 1576 rows unloaded . Unloading table col$ 55264 rows unloaded . Unloading table user$ rows unloaded Reading USER.dat Entries Loaded Reading OBJ.dat 51171 entries loaded and sorted 51171 entries Reading TAB.dat 1576 Entries loaded Reading COL.dat 55264 entries loaded and sorted 55264 entries Reading BOOTSTRAP.dat Entries Loaded DUL:Warning:Recreating file "Dict.ddl" Generating DICT.DDL for version 10 obj$: Segobjno, file 1 Block 121 tab$: Segobjno 2, tabno 1, file 1 Block 25 col$: Segobjno 2, tabno 5, file 1 Block 25 user$: Segobjno, tabno 1, file 1 block 89 tabpart$: Segobjno 266, file 1 block 2121 indpart$: Segobjno 271, file 1 block 2161 tabcompart$: Segobjno, file 1 Block 2297 indcompart$: Segobjno 293, file 1 block 2345 tabsubpart$: Segobjno 278, file 1 block 2217 indsubpart$: Segobjno 283, file 1 Block 2257 ind$: Segobjno 2, tabno 3, file 1 Block 25 icol$: Segobjno 2, tabno 4, file 1 Block 25 lob$: Segobjno 2, tabno 6, file 1 Block 25 coltype$: Segobjno 2, tabno 7, file 1 Block 25 type$: Segobjno 181, Tabno 1, file 1 block 1297 collection$: Segobjno 181, Tabno 2, file 1 block 1297 attribute$: Segobjno 181, Tabno 3, file 1 block 1297 lobfrag$: Segobjno 299, file 1 block 2393 lobcomppart$: Segobjno 302, file 1 block 2425 undo$: Segobjno, file 1 Block 105 ts$: Segobjno 6, Tabno 2, file 1 Block 57 props$: Segobjno, file 1 block 721 Running generated file "@dict. DDL" to unload the dictionary tables . Unloading table Www.111cn.net obj$ DUL:Warning:Recreating file "Obj.ctl" 51171 rows unloaded . Unloading table tab$ DUL:Warning:Recreating file "Tab.ctl" 1576 rows unloaded . Unloading table col$ DUL:Warning:Recreating file "Col.ctl" 55264 Rows unloaded . Unloading table user$ DUL:Warning:Recreating file "User.ctl" Unloaded rows . Unloading table tabpart$ rows unloaded . Unloading table indpart$ rows unloaded . Unloading table tabcompart$ 0 rows unloaded . Unloading table indcompart$ 0 rows unloaded . Unloading table tabsubpart$ 0 rows unloaded . Unloading table indsubpart$ 0 rows unloaded . Unloading table ind$ 2231 rows unloaded . Unloading table icol$ 3650 rows unloaded . Unloading table lob$ 530 rows unloaded . Unloading table coltype$ 1701 rows unloaded . Unloading table type$ 1945 rows unloaded . Unloading table collection$ 555 rows unloaded . Unloading table attribute$ 7275 rows unloaded . Unloading table lobfrag$ 1 row unloaded . Unloading table lobcomppart$ 0 rows unloaded . Unloading table undo$ rows unloaded . Unloading table ts$ 7 rows unloaded . Unloading table props$ rows unloaded Reading USER.dat Entries Loaded Reading OBJ.dat 51171 entries loaded and sorted 51171 entries Reading TAB.dat 1576 Entries loaded Reading COL.dat 55264 entries loaded and sorted 55264 entries Reading TABPART.dat entries loaded and sorted entries Reading TABCOMPART.dat 0 Entries loaded and sorted 0 entries Reading TABSUBPART.dat 0 Entries loaded and sorted 0 entries Reading INDPART.dat entries loaded and sorted entries Reading INDCOMPART.dat 0 Entries loaded and sorted 0 entries Reading INDSUBPART.dat 0 Entries loaded and sorted 0 entries Reading IND.dat 2231 Entries loaded Reading LOB.dat 530 Entries loaded Reading ICOL.dat 3650 Entries loaded Reading COLTYPE.dat 1701 Entries loaded Reading TYPE.dat 1945 Entries loaded Reading ATTRIBUTE.dat 7275 Entries loaded Reading COLLECTION.dat 555 Entries loaded Reading BOOTSTRAP.dat Entries Loaded Reading LOBFRAG.dat 1 entries loaded and sorted 1 entries Reading LOBCOMPPART.dat 0 Entries loaded and sorted 0 entries Reading UNDO.dat Entries Loaded Reading TS.dat 7 Entries loaded Reading PROPS.dat Entries Loaded Database Character Set is ZHS16GBK Database national Character set is AL16UTF16 dul> unload table Sys.t_xifenfei; . Unloading table T_xifenfei 50031 rows unloaded

It can be found here that we create the test data is 50,031, Dul read extracted data files in the corresponding table data bar number is also 50,031; proof: When the ASM disk header is completely damaged, you can scan the data file to find the datafile in the disk. Block implementation full recovery data [can be recovered by this method as long as the data in your ASM is not overwritten]