如果数据存放于asm磁盘组之上，当asm磁盘组无法mount起来，则意味着无法打开数据库。我们假设磁盘头部没有损坏，只是盘符变了，但无法正确设置asm_diskstring参数。 实验环境： RHEL5 + ORACLE10.2.0.4RAC+RAW+ASM 通过此次实验你将掌握以下知识点： 1. 初步
如果数据存放于asm磁盘组之上，当asm磁盘组无法mount起来，则意味着无法打开数据库。我们假设磁盘头部没有损坏，只是盘符变了，但无法正确设置asm_diskstring参数。
实验环境： RHEL5 + ORACLE10.2.0.4RAC+RAW+ASM
通过此次实验你将掌握以下知识点：
1. 初步了解如何使用ORACLE两款内部工具amdu/kfed
2. 在ASM磁盘组无法MOUNT的情况下，如何对应物理磁盘和ASMDISK的关系
3. 当ASM_DISKSTRING设置不全时，如何补全并将磁盘组MOUNT起来。
SQL> ALTER DISKGROUP ALL MOUNT Sat Nov 29 22:15:09 2014 NOTE: cache registered group DATA number=1 incarn=0x5bc84523 Sat Nov 29 22:15:09 2014 NOTE: Hbeat: instance first (grp 1) Sat Nov 29 22:15:13 2014 NOTE: start heartbeating (grp 1) NOTE: cache opening disk 0 of grp 1: DATA_0000 path:/dev/raw/raw3 <<<<<<< Sat Nov 29 22:15:13 2014 NOTE: F1X0 found on disk 0 fcn 0.619 NOTE: cache opening disk 1 of grp 1: DATA_0001 path:/dev/raw/raw4 <<<<<<< NOTE: cache mounting (first) group 1/0x5BC84523 (DATA) * allocate domain 1, invalid = TRUE Sat Nov 29 22:15:13 2014 NOTE: attached to recovery domain 1 Sat Nov 29 22:15:13 2014 NOTE: starting recovery of thread=1 ckpt=23.573 group=1 NOTE: advancing ckpt for thread=1 ckpt=23.573 NOTE: cache recovered group 1 to fcn 0.5267 Sat Nov 29 22:15:13 2014 NOTE: opening chunk 1 at fcn 0.5267 ABA NOTE: seq=24 blk=574 Sat Nov 29 22:15:13 2014 NOTE: cache mounting group 1/0x5BC84523 (DATA) succeeded SUCCESS: diskgroup DATA was mounted
下面我们取消raw3,raw4裸设备的定义，重启操作系统...
SQL> alter diskgroup all mount; alter diskgroup all mount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15063: ASM discovered an insufficient number of disks for diskgroup "DATA" SQL> alter system set asm_diskstring='/dev/sdd1'; <<<<<此处只添加一块盘符 System altered. SQL> alter diskgroup data mount; alter diskgroup data mount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15040: diskgroup is incomplete ORA-15042: ASM disk "1" is missing <<<<<<依旧缺失一块盘符 [oracle@dwdb1 tmp]$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:`pwd` [oracle@dwdb1 tmp]$ ./amdu -diskstring='/dev/sd*' -dump 'DATA' <<<<<扫描/dev/sd*所有设备 [oracle@dwdb1 tmp]$ cd amdu_2014_11_30_08_28_26 [oracle@dwdb1 amdu_2014_11_30_08_28_26]$ ls -lrt total 94364 -rw-r--r-- 1 oracle oinstall 7231 Nov 30 08:28 report.txt -rw-r--r-- 1 oracle oinstall 8000 Nov 30 08:28 DATA.map -rw-r--r-- 1 oracle oinstall 96514048 Nov 30 08:28 DATA_0001.img
截取部分report.txt内容:
----------------------------- DISK REPORT N0010 ------------------------------ Disk Path: /dev/sdd1 Unique Disk ID: Disk Label: Physical Sector Size: 512 bytes Disk Size: 1019 megabytes Group Name: DATA Disk Name: DATA_0000 Failure Group Name: DATA_0000 Disk Number: 0 Header Status: 3 Disk Creation Time: 2014/11/05 12:55:10.506000 Last Mount Time: 2014/11/29 23:14:47.663000 Compatibility Version: 0x0a100000 Disk Sector Size: 512 bytes Disk size in AUs: 1019 AUs Group Redundancy: 1 Metadata Block Size: 4096 bytes AU Size: 1048576 bytes Stride: 113792 AUs Group Creation Time: 2014/11/05 12:55:10.486000 File 1 Block 1 location: AU 2 ----------------------------- DISK REPORT N0012 ------------------------------ Disk Path: /dev/sde1 <<<<<<<<<<<<<<<<<磁盘全路径 Unique Disk ID: Disk Label: Physical Sector Size: 512 bytes Disk Size: 1019 megabytes Group Name: DATA Disk Name: DATA_0001 Failure Group Name: DATA_0001 Disk Number: 1 <<<<<<<<<<<<<<<<<<<<<<<<<磁盘序号为1 Header Status: 3 Disk Creation Time: 2014/11/05 13:01:56.714000 Last Mount Time: 2014/11/29 23:14:47.663000 Compatibility Version: 0x0a100000 Disk Sector Size: 512 bytes Disk size in AUs: 1019 AUs Group Redundancy: 1 Metadata Block Size: 4096 bytes AU Size: 1048576 bytes Stride: 113792 AUs Group Creation Time: 2014/11/05 12:55:10.486000 File 1 Block 1 location: AU 0 ... ------------------------- SUMMARY FOR DISKGROUP DATA ------------------------- Allocated AU's: 1632 Free AU's: 406 AU's read for dump: 100 Block images saved: 23563 Map lines written: 100 Heartbeats seen: 0 Corrupt metadata blocks: 0 Corrupt AT blocks: 0 ******************************* END OF REPORT ********************************
结合以上信息，使用KFED再次确认：
[oracle@dwdb1 tmp]$ kfed read /dev/sde1 |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: T=0 NUMB=0x0 kfbh.block.obj: 2147483649 ; 0x008: TYPE=0x8 NUMB=0x1 kfbh.check: 1289251580 ; 0x00c: 0x4cd86afc 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: 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: 168820736 ; 0x020: 0x0a100000 kfdhdb.dsknum: 1 ; 0x024: 0x0001 kfdhdb.grptyp: 1 ; 0x026: KFDGTP_EXTERNAL kfdhdb.hdrsts: 3 ; 0x027: KFDHDR_MEMBER 这样,就可以确定disk1就为/dev/sde1了 SQL> alter system set asm_diskstring='/dev/sdd1','/dev/sde1'; System altered. SQL> alter diskgroup data mount; Diskgroup altered.
接下来就可以启动数据库了。
以上简单地使用了AMDU/KFED命令，这两款具都可以实现在ASM磁盘组无法MOUNT的情况下对磁盘读写，其中KFED命令还可以用于磁盘头部的修复(10.2.5.0以上的数据库全有自动备份)，还可以做异常恢复：从ASM磁盘直接恢复数据文件，总之也是个非常强大的工具。
