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标题：asm磁盘分区丢失恢复
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.]
有朋友反馈，他们做了xx存储的双活之后，重启主机发现gi无法正常启动，分析发现所有该存储的磁盘分区信息丢失，导致asmlib无法发现磁盘(使用分区做asm disk)
类似如下错误(磁盘分区丢失)
--fdisk -l 显示部分结果 Disk /dev/mapper/datahds1: 1099.5 GB, 1099511627776 bytes 255 heads, 63 sectors/track, 133674 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 --ls -l /dev/mapper/ 显示结果无分区信息 lrwxrwxrwx 1 root root 7 May 6 03:44 datahds1 -> ../dm-1 lrwxrwxrwx 1 root root 7 May 6 03:26 datahds2 -> ../dm-3 lrwxrwxrwx 1 root root 7 May 6 03:26 datahds3 -> ../dm-8 lrwxrwxrwx 1 root root 7 May 6 03:26 ocrhds1 -> ../dm-0 lrwxrwxrwx 1 root root 7 May 6 03:26 ocrhds2 -> ../dm-2 lrwxrwxrwx 1 root root 7 May 6 03:26 ocrhds3 -> ../dm-4
asm日志显示
SUCCESS: diskgroup DATADG was mounted NOTE: Instance updated compatible.asm to 11.2.0.0.0 for grp 3 SUCCESS: diskgroup OCRHDS was mounted ORA-15032: not all alterations performed ORA-15017: diskgroup "DATA" cannot be mounted ORA-15063: ASM discovered an insufficient number of disks for diskgroup "DATA"
分析系统日志
May 6 02:23:27 db2 kernel: sdb: unknown partition table May 6 02:23:27 db2 kernel: sde: unknown partition table May 6 02:23:27 db2 kernel: sdc: unknown partition table May 6 02:23:27 db2 kernel: sdf: unknown partition table May 6 02:23:27 db2 kernel: sdd: unknown partition table May 6 02:23:27 db2 kernel: sdj:Dev sdj: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sdi: sdi1 May 6 02:23:27 db2 kernel: sdk: sdk1 May 6 02:23:27 db2 kernel: sdg: unknown partition table May 6 02:23:27 db2 kernel: sdl: sdl1 May 6 02:23:27 db2 kernel: sdm:Dev sdm: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sdo:Dev sdo: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sdn:Dev sdn: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sdp:Dev sdp: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sds:Dev sds: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sdh: May 6 02:23:27 db2 kernel: sdt: sdt1 May 6 02:23:27 db2 kernel: sdv:Dev sdv: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sdq:Dev sdq: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sd 1:0:1:9: [sdr] Very big device. Trying to use READ CAPACITY(16). May 6 02:23:27 db2 kernel: sdr:Dev sdr: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sd 2:0:0:9: [sdab] Very big device. Trying to use READ CAPACITY(16). May 6 02:23:27 db2 kernel: sdab: unknown partition table May 6 02:23:27 db2 kernel: sdac: unknown partition table May 6 02:23:27 db2 kernel: sdw: sdw1 May 6 02:23:27 db2 kernel: sdu:Dev sdu: unable to read RDB block 0 May 6 02:23:27 db2 kernel: unable to read partition table May 6 02:23:27 db2 kernel: sdx: sdx1 May 6 02:23:27 db2 kernel: sdy: sdy1 May 6 02:23:27 db2 kernel: sdaa: sdaa1 May 6 02:23:27 db2 kernel: sdz: sdz1 May 6 02:23:27 db2 kernel: sdae: unknown partition table May 6 02:23:27 db2 kernel: sdaf: unknown partition table May 6 02:23:27 db2 kernel: sdag: unknown partition table May 6 02:23:27 db2 kernel: sdai: May 6 02:23:27 db2 kernel: sdah: unknown partition table May 6 02:23:27 db2 kernel: sdad: unknown partition table May 6 02:23:28 db2 mcelog: failed to prefill DIMM database from DMI data
这里错误比较明显unknown partition table，磁盘的分区信息损坏.使用fdisk无法发现分区
partprobe也无效
[root@db2 oracle]# partprobe /dev/mapper/ocrhds3 [root@db2 oracle]# [root@db2 oracle]# ls -l /dev/mapper/ocrhds3* lrwxrwxrwx 1 root root 7 May 6 07:30 /dev/mapper/ocrhds3 -> ../dm-4
从尚需信息看，磁盘的分区表信息应该已经损坏，现在能够做的，就是希望运气好，磁盘的分区的实际数据没有损坏
分析磁盘实际分区数据
[root@db2 ~]$ dd if=/dev/mapper/datahds1 of=/tmp/datahds1.dd bs=1024k count=50 [root@db2 ~]$ dd if=/tmp/datahds1.dd of=/tmp/xff01.dd bs=3225 skip=1 [grid@db2 ~]$ kfed read /tmp/xff01.dd |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: 0 ; 0x004: blk=0 kfbh.block.obj: 2147483648 ; 0x008: disk=0 kfbh.check: 3110278718 ; 0x00c: 0xb963163e kfbh.fcn.base: 0 ; 0x010: 0x00000000 kfbh.fcn.wrap: 0 ; 0x014: 0x00000000 kfbh.spare1: 0 ; 0x018: 0x00000000 kfbh.spare2: 0 ; 0x01c: 0x00000000 kfdhdb.driver.provstr: ORCLDISKHDSDATA1 ; 0x000: length=16 kfdhdb.driver.reserved[0]: 1146307656 ; 0x008: 0x44534448 kfdhdb.driver.reserved[1]: 826364993 ; 0x00c: 0x31415441 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: DATADG_0000 ; 0x028: length=11 kfdhdb.grpname: DATADG ; 0x048: length=6 kfdhdb.fgname: DATADG_0000 ; 0x068: length=11 kfdhdb.capname: ; 0x088: length=0 kfdhdb.crestmp.hi: 33050696 ; 0x0a8: HOUR=0x8 DAYS=0x2 MNTH=0x4 YEAR=0x7e1 kfdhdb.crestmp.lo: 3813740544 ; 0x0ac: USEC=0x0 MSEC=0x44 SECS=0x35 MINS=0x38 kfdhdb.mntstmp.hi: 33050701 ; 0x0b0: HOUR=0xd DAYS=0x2 MNTH=0x4 YEAR=0x7e1 kfdhdb.mntstmp.lo: 411385856 ; 0x0b4: USEC=0x0 MSEC=0x150 SECS=0x8 MINS=0x6
通过上述分析，我们可以初步判断，分区磁盘的信息很可能是好的(因为asm disk header是好的，根据一般的规则从前往后覆盖，既然header是好的，后面的block被覆盖的概率非常小)
通过准备新磁盘直接把磁盘分区dd到新设备上
dd if=/dev/mapper/ocrhds1 of=/dev/mapper/ocrhdsnew1 skip=1 bs=3225 dd if=/dev/mapper/ocrhds2 of=/dev/mapper/ocrhdsnew2 skip=1 bs=3225 dd if=/dev/mapper/ocrhds3 of=/dev/mapper/ocrhdsnew3 skip=1 bs=3225 dd if=/dev/mapper/datahds1 of=/dev/mapper/datahdsnew1 skip=1 bs=3225 dd if=/dev/mapper/datahds2 of=/dev/mapper/datahdsnew2 skip=1 bs=3225 dd if=/dev/mapper/datahds3 of=/dev/mapper/datahdsnew3 skip=1 bs=3225
asmlib重新扫描磁盘
[root@db1 disks]# oracleasm scandisks Reloading disk partitions: done Cleaning any stale ASM disks... Scanning system for ASM disks... Instantiating disk "HDSOCR3" Instantiating disk "HDSDATA2" Instantiating disk "HDSDATA1" Instantiating disk "HDSDATA3" Instantiating disk "HDSOCR1" Instantiating disk "HDSOCR2" [root@db1 disks]# ls -ltr total 0 brw-rw---- 1 grid asmadmin 8, 160 May 6 13:49 HDSOCR3 brw-rw---- 1 grid asmadmin 8, 192 May 6 13:49 HDSDATA2 brw-rw---- 1 grid asmadmin 8, 176 May 6 13:49 HDSDATA1 brw-rw---- 1 grid asmadmin 8, 208 May 6 13:49 HDSDATA3 brw-rw---- 1 grid asmadmin 8, 128 May 6 13:49 HDSOCR1 brw-rw---- 1 grid asmadmin 8, 144 May 6 13:49 HDSOCR2
kfed验证拷贝的分区
[root@db2 tmp]# /oracle/app/11.2.0/grid_1/bin/kfed read /dev/oracleasm/disks/HDSDATA1 kfbh.endian: 1 ; 0x000: 0x01 kfbh.hard: 130 ; 0x001: 0x82 kfbh.type: 1 ; 0x002: KFBTYP_DISKHEAD kfbh.datfmt: 1 ; 0x003: 0x01 kfbh.block.blk: 0 ; 0x004: blk=0 kfbh.block.obj: 2147483648 ; 0x008: disk=0 kfbh.check: 3110278718 ; 0x00c: 0xb963163e kfbh.fcn.base: 0 ; 0x010: 0x00000000 kfbh.fcn.wrap: 0 ; 0x014: 0x00000000 kfbh.spare1: 0 ; 0x018: 0x00000000 kfbh.spare2: 0 ; 0x01c: 0x00000000 kfdhdb.driver.provstr: ORCLDISKHDSDATA1 ; 0x000: length=16 kfdhdb.driver.reserved[0]: 1146307656 ; 0x008: 0x44534448 kfdhdb.driver.reserved[1]: 826364993 ; 0x00c: 0x31415441 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: DATADG_0000 ; 0x028: length=11 kfdhdb.grpname: DATADG ; 0x048: length=6 kfdhdb.fgname: DATADG_0000 ; 0x068: length=11 kfdhdb.capname: ; 0x088: length=0
asm和数据库启动正常
[grid@db2 ~]$ asmcmd ASMCMD> lsdg State Type Rebal Sector Block AU Total_MB Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name MOUNTED EXTERN N 512 4096 1048576 3145710 2378034 0 2378034 0 N DATADG/ MOUNTED NORMAL N 512 4096 1048576 15342 14416 5114 4651 0 Y OCRHDS/ ASMCMD> [oracle@db2 ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.4.0 Production on Sat May 6 13:54:21 2017 Copyright (c) 1982, 2013, Oracle. All rights reserved. Connected to an idle instance. SQL> startup ORACLE instance started. Total System Global Area 3.6077E+10 bytes Fixed Size 2260648 bytes Variable Size 7247757656 bytes Database Buffers 2.8723E+10 bytes Redo Buffers 104382464 bytes Database mounted. Database opened. SQL>
通过上述恢复，实现asm磁盘分区丢失数据0丢失
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