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Oracle Asm 格式 ext4文件系统---Asm 终极恢复

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标题：oracle asm disk格式化恢复—格式化为ext4文件系统

作者：惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

昨天中午接到一位朋友紧急求救电话,大概场景如下,asm data磁盘组一共把个asm disk,但是使用4个lun实现的(也就是说每个lun使用fdisk进行分区),该主机上还有一个lun是用来存放备份的挂载在/xifenfei目录.客户记得他们的/xifenfei目录是/dev/sdh1这个分区,上次主机重启之后,rac工作正常,但是/xifenfei这个目录对应的/dev/sdh1无法挂载上去(提示无法找到超级块).然后我这位朋友上去也不管三七二一直接执行了mkfs.ext4 /dev/sdh1.结果整个asm 磁盘组异常了.最后他通过fdisk命令一看发现完蛋了,以前的/dev/sdh 已经变为了/dev/sdc,而现在的/dev/sdh是以前的asm disk.也就是说,他把asm 磁盘组中的一个disk进行了格式化为ext4文件系统操作.
ext4文件系统大概结构
通过这里大概可以发现在格式化为ext4文件系统并非把所有的磁盘数据全部重写主要就是覆盖一些ext4必要的一些元数据信息,理论上没有覆盖部分的数据依旧可以恢复
ext4

fdisk 分析现在磁盘情况

 

[root@db3 ~]#  fdisk -l
 
Disk /dev/sda: 171.8 GB, 171798691840 bytes
255 heads, 63 sectors/track, 20886 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00055b12
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          64      512000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              64        8223    65536000   82  Linux swap / Solaris
/dev/sda3            8223       20887   101723136   8e  Linux LVM
 
Disk /dev/sdb: 751.6 GB, 751619276800 bytes
255 heads, 63 sectors/track, 91379 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00b6888f
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1       91379   734001786    5  Extended
/dev/sdb5               1       15000   120487437   83  Linux
 
Disk /dev/sdd: 1073 MB, 1073741824 bytes
34 heads, 61 sectors/track, 1011 cylinders
Units = cylinders of 2074 * 512 = 1061888 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00083b68
 
   Device Boot      Start         End      Blocks   Id  System
 
Disk /dev/sdf: 526.1 GB, 526133493760 bytes
255 heads, 63 sectors/track, 63965 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000c10d8
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sdf1               1       13054   104856223+  83  Linux
/dev/sdf2           13055       63965   408942607+  83  Linux
 
Disk /dev/sde: 1073 MB, 1073741824 bytes
34 heads, 61 sectors/track, 1011 cylinders
Units = cylinders of 2074 * 512 = 1061888 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000b120f
 
   Device Boot      Start         End      Blocks   Id  System
 
Disk /dev/sdc: 1795.3 GB, 1795296329728 bytes
255 heads, 63 sectors/track, 218265 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x78c377f7
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1               1      218265  1753213581   83  Linux
 
Disk /dev/sdg: 526.1 GB, 526133493760 bytes
255 heads, 63 sectors/track, 63965 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000ee648
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sdg1               1       13054   104856223+  83  Linux
/dev/sdg2           13055       63965   408942607+  83  Linux
 
Disk /dev/sdi: 526.1 GB, 526133493760 bytes
255 heads, 63 sectors/track, 63965 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00027e4b
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sdi1               1       13054   104856223+  83  Linux
/dev/sdi2           13055       63965   408942607+  83  Linux
 
Disk /dev/sdh: 526.1 GB, 526133493760 bytes
255 heads, 63 sectors/track, 63965 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000938dc
 
   Device Boot      Start         End      Blocks   Id  System
/dev/sdh1               1       13054   104856223+  83  Linux
/dev/sdh2           13055       63965   408942607+  83  Linux
 
Disk /dev/mapper/rootvg-rootfs: 31.7 GB, 31708938240 bytes
255 heads, 63 sectors/track, 3855 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
 
 
Disk /dev/mapper/rootvg-lv01: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

通过asm alert日志确定asm disk信息
这里可以确定asm disk是VOL01-VOL08一共8个盘

SQL> CREATE DISKGROUP DATA EXTERNAL REDUNDANCY  DISK '/dev/oracleasm/disks/VOL01',
'/dev/oracleasm/disks/VOL02',
'/dev/oracleasm/disks/VOL03',
'/dev/oracleasm/disks/VOL04' ATTRIBUTE 'compatible.asm'='11.2.0.0.0','au_size'='1M' /* ASMCA */
 
SQL> ALTER DISKGROUP DATA ADD  DISK '/dev/oracleasm/disks/VOL05' SIZE 399358M ,
'/dev/oracleasm/disks/VOL06' SIZE 399358M ,
'/dev/oracleasm/disks/VOL07' SIZE 399358M ,
'/dev/oracleasm/disks/VOL08' SIZE 399358M /* ASMCA */
 
SQL> ALTER DISKGROUP ALL MOUNT /* asm agent call crs *//* {0:0:2} */
NOTE: Diskgroup used for Voting files is:
     DATA
Diskgroup with spfile:DATA
Diskgroup used for OCR is:DATA
NOTE: cache registered group DATA number=1 incarn=0x6f3f6eb8
NOTE: cache began mount (not first) of group DATA number=1 incarn=0x6f3f6eb8
NOTE: Assigning number (1,7) to disk (/dev/oracleasm/disks/VOL08)
NOTE: Assigning number (1,6) to disk (/dev/oracleasm/disks/VOL07)
NOTE: Assigning number (1,5) to disk (/dev/oracleasm/disks/VOL06)
NOTE: Assigning number (1,4) to disk (/dev/oracleasm/disks/VOL05)
NOTE: Assigning number (1,3) to disk (/dev/oracleasm/disks/VOL04)
NOTE: Assigning number (1,1) to disk (/dev/oracleasm/disks/VOL02)
NOTE: Assigning number (1,2) to disk (/dev/oracleasm/disks/VOL03)
NOTE: Assigning number (1,0) to disk (/dev/oracleasm/disks/VOL01)
GMON querying group 1 at 2 for pid 23, osid 32026
NOTE: cache opening disk 0 of grp 1: DATA_0000 path:/dev/oracleasm/disks/VOL01
NOTE: cache opening disk 1 of grp 1: DATA_0001 path:/dev/oracleasm/disks/VOL02
NOTE: cache opening disk 2 of grp 1: DATA_0002 path:/dev/oracleasm/disks/VOL03
NOTE: cache opening disk 3 of grp 1: DATA_0003 path:/dev/oracleasm/disks/VOL04
NOTE: cache opening disk 4 of grp 1: DATA_0004 path:/dev/oracleasm/disks/VOL05
NOTE: cache opening disk 5 of grp 1: DATA_0005 path:/dev/oracleasm/disks/VOL06
NOTE: cache opening disk 6 of grp 1: DATA_0006 path:/dev/oracleasm/disks/VOL07
NOTE: cache opening disk 7 of grp 1: DATA_0007 path:/dev/oracleasm/disks/VOL08
NOTE: cache mounting (not first) external redundancy group 1/0x6F3F6EB8 (DATA)

查询asm对应的disk信息
这部分信息,可以确定VOL03被格式化,而且应该就是朋友反馈的被他格式化成ext4的/dev/sdh1
asm1

[root@db3 disks]# ls
VOL01  VOL02  VOL04  VOL05  VOL06  VOL07  VOL08
[root@db3 disks]# oracleasm querydisk -p 'VOL01'
Disk "VOL01" is a valid ASM disk
/dev/sdf1: LABEL="VOL01" TYPE="oracleasm"
[root@db3 disks]# oracleasm querydisk -p 'VOL02'
Disk "VOL02" is a valid ASM disk
/dev/sdg1: LABEL="VOL02" TYPE="oracleasm"
[root@db3 disks]# oracleasm querydisk -p 'VOL03'
Disk "VOL03" does not exist or is not instantiated
[root@db3 disks]# oracleasm querydisk -p 'VOL04'
Disk "VOL04" is a valid ASM disk
/dev/sdi1: LABEL="VOL04" TYPE="oracleasm"
[root@db3 disks]# oracleasm querydisk -p 'VOL05'
Disk "VOL05" is a valid ASM disk
/dev/sdf2: LABEL="VOL05" TYPE="oracleasm"
[root@db3 disks]# oracleasm querydisk -p 'VOL06'
Disk "VOL06" is a valid ASM disk
/dev/sdg2: LABEL="VOL06" TYPE="oracleasm"
[root@db3 disks]# oracleasm querydisk -p 'VOL07'
Disk "VOL07" is a valid ASM disk
/dev/sdh2: LABEL="VOL07" TYPE="oracleasm"
[root@db3 disks]# oracleasm querydisk -p 'VOL08'
Disk "VOL08" is a valid ASM disk
/dev/sdi2: LABEL="VOL08" TYPE="oracleasm"

通过kfed分析被格式化成ext4的磁盘信息

[grid@db3 ~]$ kfed read /dev/sdh1
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: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
kfbh.check:                   810307429 ; 0x00c: 0x304c4f65
kfbh.fcn.base:                        0 ; 0x010: 0x00000000
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
000000000 00000000 00000000 00000000 304C4F65  [............eOL0]
000000010 00000000 00000000 00000000 00000000  [................]
000000020 4C43524F 44524C43 00000000 00000000  [ORCLCLRD........]
000000030 00000000 00000000 00000000 00000000  [................]
  Repeat 252 times
KFED-00322: Invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]
 
 
[grid@db3 ~]$ kfed read /dev/sdh1 aun=1
kfbh.endian:                          0 ; 0x000: 0x00
kfbh.hard:                          129 ; 0x001: 0x81
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                   98560 ; 0x004: blk=98560
kfbh.block.obj:                  164096 ; 0x008: file=164096
kfbh.check:                      229632 ; 0x00c: 0x00038100
kfbh.fcn.base:                   295168 ; 0x010: 0x00048100
kfbh.fcn.wrap:                   819456 ; 0x014: 0x000c8100
kfbh.spare1:                     884992 ; 0x018: 0x000d8100
kfbh.spare2:                    1605888 ; 0x01c: 0x00188100
000100000 00008100 00018100 00028100 00038100  [................]
000100010 00048100 000C8100 000D8100 00188100  [................]
000100020 00288100 003E8100 00798100 00AB8100  [..(...>...y.....]
000100030 01388100 016C8100 00000000 00000000  [..8...l.........]
000100040 00000000 00000000 00000000 00000000  [................]
  Repeat 251 times
KFED-00322: Invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]
 
 
[grid@db3 ~]$ kfed read /dev/sdh1 aun=1 blkn=254
kfbh.endian:                        254 ; 0x000: 0xfe
kfbh.hard:                          129 ; 0x001: 0x81
kfbh.type:                            0 ; 0x002: KFBTYP_INVALID
kfbh.datfmt:                          0 ; 0x003: 0x00
kfbh.block.blk:                   98814 ; 0x004: blk=98814
kfbh.block.obj:                  164350 ; 0x008: file=164350
kfbh.check:                      229886 ; 0x00c: 0x000381fe
kfbh.fcn.base:                   295422 ; 0x010: 0x000481fe
kfbh.fcn.wrap:                   819710 ; 0x014: 0x000c81fe
kfbh.spare1:                     885246 ; 0x018: 0x000d81fe
kfbh.spare2:                    1606142 ; 0x01c: 0x001881fe
0001FE000 000081FE 000181FE 000281FE 000381FE  [................]
0001FE010 000481FE 000C81FE 000D81FE 001881FE  [................]
0001FE020 002881FE 003E81FE 007981FE 00AB81FE  [..(...>...y.....]
0001FE030 013881FE 016C81FE 00000000 00000000  [..8...l.........]
0001FE040 00000000 00000000 00000000 00000000  [................]
  Repeat 251 times
KFED-00322: Invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]
 
 
[grid@db3 ~]$ kfed read /dev/sdh1 aun=9
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: blk=0
kfbh.block.obj:                       0 ; 0x008: file=0
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
000900000 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: Invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

从这里可以看出来该asm的元数据信息大量被破坏(asm 备份的磁盘头也损坏),直接修复的可能性基本上为0,现在为了最大限度的恢复数据,通过底层扫描asm au结合数据库block信息,进行重组出来数据文件(这次的恢复有点难度,因为该asm磁盘组中有两个数据库,需要通过结合asm file+datafile来区分文件)
恢复出来两套库的数据文件信息

/orabak/xifenfei/oradb/1.dbf
/orabak/xifenfei/oradb/2.dbf
/orabak/xifenfei/oradb/3.dbf
/orabak/xifenfei/oradb/4.dbf
/orabak/xifenfei/oradb/5.dbf
/orabak/xifenfei/oradb/6.dbf
/orabak/xifenfei/oradb/7.dbf
/orabak/xifenfei/oradb/8.dbf
/orabak/xifenfei/oradb/9.dbf
/orabak/xifenfei/oradb/10.dbf
/orabak/xifenfei/oradb/11.dbf
/orabak/xifenfei/oradb/12.dbf
/orabak/xifenfei/oradb/13.dbf
/orabak/xifenfei/oradb/14.dbf
/orabak/xifenfei/oradb/15.dbf
/orabak/xifenfei/oradb/16.dbf
/orabak/xifenfei/oradb/17.dbf
/orabak/xifenfei/oradb/18.dbf
/orabak/xifenfei/oradb/19.dbf
 
/orabak/xifenfei/xgdb/1.dbf
/orabak/xifenfei/xgdb/2.dbf
/orabak/xifenfei/xgdb/3.dbf
/orabak/xifenfei/xgdb/4.dbf
/orabak/xifenfei/xgdb/5.dbf
/orabak/xifenfei/xgdb/6.dbf
/orabak/xifenfei/xgdb/7.dbf
/orabak/xifenfei/xgdb/8.dbf
/orabak/xifenfei/xgdb/9.dbf
/orabak/xifenfei/xgdb/10.dbf
/orabak/xifenfei/xgdb/11.dbf
/orabak/xifenfei/xgdb/12.dbf
/orabak/xifenfei/xgdb/13.dbf
/orabak/xifenfei/xgdb/14.dbf
/orabak/xifenfei/xgdb/15.dbf
/orabak/xifenfei/xgdb/16.dbf

然后使用工具拷贝出来redo信息,最后通过重建控制文件.其中一套库完美直接open,另外一套库system中的c_obj$被覆盖,不过使用一个多月以前的备份的system文件强制打开库成功,数据基本上完美导出,实现完美恢复.由于在格式化为ext4的时候,会在磁盘中部分位置写入一些
数据文件恢复参考:asm disk header 彻底损坏恢复
另外有一次win平台类似恢复经历:asm disk格式化为ntfs恢复

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