ORA-15063: ASM discovered an insufficient number of disks for diskgroup 恢复

客户反馈三个磁盘组无法正常mount,报错类似ORA-15032 ORA-15017 ORA-15063

SQL> ALTER DISKGROUP ASM_DATA MOUNT  /* asm agent *//* {0:0:2} */ 
NOTE: cache registered group ASM_DATA number=1 incarn=0xffa85ccd
NOTE: cache began mount (first) of group ASM_DATA number=1 incarn=0xffa85ccd
ERROR: no read quorum in group: required 2, found 0 disks
NOTE: cache dismounting (clean) group 1/0xFFA85CCD (ASM_DATA) 
NOTE: messaging CKPT to quiesce pins Unix process pid: 5709, image: oracle@XFF (TNS V1-V3)
NOTE: dbwr not being msg'd to dismount
NOTE: lgwr not being msg'd to dismount
NOTE: cache dismounted group 1/0xFFA85CCD (ASM_DATA) 
NOTE: cache ending mount (fail) of group ASM_DATA number=1 incarn=0xffa85ccd
NOTE: cache deleting context for group ASM_DATA 1/0xffa85ccd
Tue Jun 21 12:24:38 2022
NOTE: No asm libraries found in the system
ASM Health Checker found 1 new failures
GMON dismounting group 1 at 16 for pid 19, osid 5709
ERROR: diskgroup ASM_DATA was not mounted
ORA-15032: not all alterations performed
ORA-15017: diskgroup "ASM_DATA" cannot be mounted
ORA-15063: ASM discovered an insufficient number of disks for diskgroup "ASM_DATA"
ERROR: ALTER DISKGROUP ASM_DATA MOUNT  /* asm agent *//* {0:0:2} */

初步判断是asm disk异常导致(比如asm disk不能被扫描到,或者丢失,或者磁盘头损坏等),分析客户的asm disk的udev文件配置

KERNEL=="sdd1", NAME="asm_grid", OWNER="grid", GROUP="asmadmin", MODE="0660"          
KERNEL=="sde1", NAME="asm_system", OWNER="grid", GROUP="asmadmin", MODE="0660"    
KERNEL=="sdf1", NAME="asm_data", OWNER="grid", GROUP="asmadmin", MODE="0660"     

从udev的配置中可以看出来,客户以前是对3个磁盘进行分析,然后使用udev映射别名给asm使用的.通过对其中一个磁盘进行分析

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通过上述winhex查看，可以确认该分区的磁盘头信息异常[该信息属于磁盘刚分区的时候信息,而不是asm disk的信息],和kfed看到的结果一致[磁盘头位置肯定损坏,其他位置目前未知]

H:\TEMP\dd>kfed read sdf_sdf1.dd
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
0064D8400 00000000 00000000 00000000 00000000  [................]
        Repeat 26 times
0064D85B0 00000000 00000000 00000000 02000000  [................]
0064D85C0 FE8E0001 003FFFFF DFFC0000 0000257F  [......?......%..]
0064D85D0 00000000 00000000 00000000 00000000  [................]
        Repeat 1 times
0064D85F0 00000000 00000000 00000000 AA550000  [..............U.]
0064D8600 00000000 00000000 00000000 00000000  [................]
  Repeat 223 times
KFED-00322: Invalid content encountered during block traversal: [kfbtTraverseBlock][Invalid OSM block type][][0]

分析其他位置的block情况,初步看基本上ok[运气还不错]

H:\TEMP\dd>kfed read sdf_sdf1.dd blkn=2|grep kfbh.type
kfbh.type:                            3 ; 0x002: KFBTYP_ALLOCTBL

H:\TEMP\dd>kfed read sdf_sdf1.dd blkn=3|grep kfbh.type
kfbh.type:                            3 ; 0x002: KFBTYP_ALLOCTBL

H:\TEMP\dd>kfed read sdf_sdf1.dd blkn=1 aun=2|grep kfbh.type
kfbh.type:                            3 ; 0x002: KFBTYP_ALLOCTBL

通过检索备份出来的部分磁盘文件,找出来ORCLDISK信息部分(asm disk header)

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然后利用这个部分对损坏的磁盘头进行修复,并且dd回生产环境中,并尝试mount磁盘组,数据库open成功

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至此这个数据库运气不错,没有过多损坏,算完美恢复,可以进行了逻辑导出和rman备份,全部正常.为了后续安全,建议对其进行迁移