dd破坏asm磁盘头恢复

有朋友对asm disk的磁盘头dd了2048byte的数据

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通过分析,gi软件版本,确认是11.2.0.4

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options.
ORACLE_HOME = /u01/app/11.2.0/grid
System name:	Linux
Node name:	rac1
Release:	4.1.12-37.4.1.el6uek.x86_64
Version:	#2 SMP Tue May 17 07:23:38 PDT 2016
Machine:	x86_64

从10.2.0.5之后版本,在第二个au的倒数第二个block上面,有asm disk header备份（每个block大小为4k）,分析au大小(通过分析正常的asm disk快速找到au 大小【使用dd备份的正常的磁盘头查看】)

H:\TEMP\tmp\asmbak>kfed read sdcp.dd |grep ausize
kfdhdb.ausize:                 16777216 ; 0x0bc: 0x01000000

找到被破坏的asm disk的备份磁盘头信息

H:\TEMP\tmp\asmbak>kfed read sdc.dd blkn=4094 aun=1 aus=16777216|more
kfbh.endian:                          1 ; 0x000: 0x01
kfbh.hard:                          130 ; 0x001: 0x82
kfbh.type:                            1 ; 0x002: KFBTYP_DISKHEAD
kfbh.datfmt:                          1 ; 0x003: 0x01
kfbh.block.blk:                    4094 ; 0x004: blk=4094
kfbh.block.obj:              2147483648 ; 0x008: disk=0
kfbh.check:                   229348702 ; 0x00c: 0x0dab955e
kfbh.fcn.base:                 11727032 ; 0x010: 0x00b2f0b8
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
kfdhdb.driver.provstr:         ORCLDISK ; 0x000: length=8
kfdhdb.driver.reserved[0]:            0 ; 0x008: 0x00000000
kfdhdb.driver.reserved[1]:            0 ; 0x00c: 0x00000000
kfdhdb.driver.reserved[2]:            0 ; 0x010: 0x00000000
kfdhdb.driver.reserved[3]:            0 ; 0x014: 0x00000000
kfdhdb.driver.reserved[4]:            0 ; 0x018: 0x00000000
kfdhdb.driver.reserved[5]:            0 ; 0x01c: 0x00000000
kfdhdb.compat:                186646528 ; 0x020: 0x0b200000
kfdhdb.dsknum:                        0 ; 0x024: 0x0000
kfdhdb.grptyp:                        1 ; 0x026: KFDGTP_EXTERNAL
kfdhdb.hdrsts:                        3 ; 0x027: KFDHDR_MEMBER
kfdhdb.dskname:               DATA_0000 ; 0x028: length=9
kfdhdb.grpname:                    DATA ; 0x048: length=4
kfdhdb.fgname:                DATA_0000 ; 0x068: length=9
kfdhdb.capname:                         ; 0x088: length=0
kfdhdb.crestmp.hi:             33123276 ; 0x0a8: HOUR=0xc DAYS=0x1e MNTH=0xa YEAR=0x7e5
kfdhdb.crestmp.lo:           2259134464 ; 0x0ac: USEC=0x0 MSEC=0x1ea SECS=0x2a MINS=0x21
kfdhdb.mntstmp.hi:             33162836 ; 0x0b0: HOUR=0x14 DAYS=0x12 MNTH=0x1 YEAR=0x7e8
kfdhdb.mntstmp.lo:           3600987136 ; 0x0b4: USEC=0x0 MSEC=0xad SECS=0x2a MINS=0x35
kfdhdb.secsize:                     512 ; 0x0b8: 0x0200
kfdhdb.blksize:                    4096 ; 0x0ba: 0x1000
kfdhdb.ausize:                 16777216 ; 0x0bc: 0x01000000
kfdhdb.mfact:                    454272 ; 0x0c0: 0x0006ee80
kfdhdb.dsksize:                   65536 ; 0x0c4: 0x00010000
kfdhdb.pmcnt:                         2 ; 0x0c8: 0x00000002
kfdhdb.fstlocn:                       1 ; 0x0cc: 0x00000001
kfdhdb.altlocn:                       2 ; 0x0d0: 0x00000002
kfdhdb.f1b1locn:                      0 ; 0x0d4: 0x00000000
kfdhdb.redomirrors[0]:                0 ; 0x0d8: 0x0000
kfdhdb.redomirrors[1]:                0 ; 0x0da: 0x0000
kfdhdb.redomirrors[2]:                0 ; 0x0dc: 0x0000
…………

确认被损坏的磁盘只有磁盘头信息损坏(即确认第二个block是否是好的)

H:\TEMP\tmp\asmbak>kfed read sdc.dd blkn=0
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
0065D8400 00000000 00000000 00000000 00000000  [................]
  Repeat 255 times
KFED-00322: Invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]


H:\TEMP\tmp\asmbak>kfed read sdc.dd blkn=1|more
kfbh.endian:                          1 ; 0x000: 0x01
kfbh.hard:                          130 ; 0x001: 0x82
kfbh.type:                            2 ; 0x002: KFBTYP_FREESPC
kfbh.datfmt:                          2 ; 0x003: 0x02
kfbh.block.blk:                       1 ; 0x004: blk=1
kfbh.block.obj:              2147483648 ; 0x008: disk=0
kfbh.check:                  2781697777 ; 0x00c: 0xa5cd56f1
kfbh.fcn.base:                 39359331 ; 0x010: 0x02589363
kfbh.fcn.wrap:                        0 ; 0x014: 0x00000000
kfbh.spare1:                          0 ; 0x018: 0x00000000
kfbh.spare2:                          0 ; 0x01c: 0x00000000
kfdfsb.aunum:                         0 ; 0x000: 0x00000000
kfdfsb.max:                        1014 ; 0x004: 0x03f6
kfdfsb.cnt:                         147 ; 0x006: 0x0093
kfdfsb.bound:                         0 ; 0x008: 0x0000
kfdfsb.flag:                          1 ; 0x00a: B=1
kfdfsb.ub1spare:                      0 ; 0x00b: 0x00
kfdfsb.spare[0]:                      0 ; 0x00c: 0x00000000
kfdfsb.spare[1]:                      0 ; 0x010: 0x00000000
kfdfsb.spare[2]:                      0 ; 0x014: 0x00000000
kfdfse[0].fse:                        0 ; 0x018: FREE=0x0 FRAG=0x0
…………

基于上述分析,直接使用备份的asm disk header信息进行merge或者repair修复之后,asm 磁盘头状态恢复正常

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这个客户运气比较好,库非常大,只是破坏了2k的数据,如果超过4k可能就是比较麻烦的事故了,再次提醒对asm磁盘的dd操作一定要小心谨慎.如果不慎破坏asm磁盘过多,参考以前类似文档:
asm磁盘dd破坏恢复