1 實驗目的

由於oracle 10g asm儲存方式是推出的第一個版本,很多功能沒完善，比如就沒有asm磁碟資訊後設資料有效的備份方式，如果誤操作導致asm磁碟頭資訊丟失，而很多人對asm磁碟頭資訊不熟悉，不得不重新建立asm磁碟組，通過備份的方式恢復資料，如果無備份的話，則導致資料丟失。雖然我已經掌握了oracle 10g asm磁碟頭資訊損壞後能夠及時恢復的技術，但操作起來還是比較麻煩。

oracle 11g已經對asmcmd工具增加了md_backup,md_restore兩個命令可以很好的備份和恢復asm磁碟組後設資料，使的這一操作變的非常簡單，下面實驗就是來學習md_backup和md_restore的使用方法。

Oracle 11g kfed、amdu檢視磁碟頭資訊命令可以直接使用，不需要再編譯。

2 實驗環境

資料庫版本	環境	資料庫名	例項名	IP地址	作業系統和主機名
所
Oracle11.2.0.1	RAC	racdb	racdb1	192.168.1.227	Linux as 5.3+rac1
Oracle11.2.0.1	RAC	racdb	Racdb2	192.168.1.228	linux as 5.3+rac2

以上環境針對於磁碟組內磁碟頭資訊丟失恢復

3 實驗步驟

3.1 md_backup 備份磁碟組後設資料

3.1.1 檢視磁碟組下的磁碟資訊

[grid@rac1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.1.0 Production on Thu Jul 8 15:24:19 2010

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production

With the Real Application Clusters and Automatic Storage Management options

SQL> select name,state from v$asm_diskgroup;

NAME STATE

------------------------------ -----------

CRS MOUNTED --CRS磁碟組(存放ocr和vote盤)

TESTDG MOUNTED

SQL> select name,path from v$asm_disk;

NAME PATH

TESTDG_0000 /dev/raw/raw1

3.1.2 用kfed讀取磁碟頭資訊

比如讀取磁碟組TESTDG下/dev/raw/raw1磁碟頭資訊

[grid@rac1 amdu_2010_07_08_15_15_18]$ kfed read /dev/raw/raw1 > /home/grid/raw1bak.txt

[grid@rac1 amdu_2010_07_08_15_15_18]$ more /home/grid/raw1bak.txt

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: 2147483648 ; 0x008: TYPE=0x8 NUMB=0x0

kfbh.check: 534688621 ; 0x00c: 0x1fdeb36d

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: 186646528 ; 0x020: 0x0b200000

kfdhdb.dsknum: 0 ; 0x024: 0x0000

kfdhdb.grptyp: 1 ; 0x026: KFDGTP_EXTERNAL

kfdhdb.hdrsts: 3 ; 0x027: KFDHDR_MEMBER

kfdhdb.dskname: TESTDG_0000 ; 0x028: length=11

kfdhdb.grpname: TESTDG ; 0x048: length=6

kfdhdb.fgname: TESTDG_0000 ; 0x068: length=11

kfdhdb.capname: ; 0x088: length=0

kfdhdb.crestmp.hi: 32939275 ; 0x0a8: HOUR=0xb DAYS=0x8 MNTH=0x7 YEAR=0x7da

kfdhdb.crestmp.lo: 3713031168 ; 0x0ac: USEC=0x0 MSEC=0x17 SECS=0x15 MINS=0x37

kfdhdb.mntstmp.hi: 32939275 ; 0x0b0: HOUR=0xb DAYS=0x8 MNTH=0x7 YEAR=0x7da

kfdhdb.mntstmp.lo: 3725327360 ; 0x0b4: USEC=0x0 MSEC=0x2ff SECS=0x20 MINS=0x37

kfdhdb.secsize: 512 ; 0x0b8: 0x0200

kfdhdb.blksize: 4096 ; 0x0ba: 0x1000

kfdhdb.ausize: 4194304 ; 0x0bc: 0x00400000

kfdhdb.mfact: 454272 ; 0x0c0: 0x0006ee80

kfdhdb.dsksize: 12799 ; 0x0c4: 0x000031ff

kfdhdb.pmcnt: 2 ; 0x0c8: 0x00000002

kfdhdb.fstlocn: 1 ; 0x0cc: 0x00000001

kfdhdb.altlocn: 2 ; 0x0d0: 0x00000002

kfdhdb.f1b1locn: 2 ; 0x0d4: 0x00000002

kfdhdb.redomirrors[0]: 0 ; 0x0d8: 0x0000

kfdhdb.redomirrors[1]: 0 ; 0x0da: 0x0000

kfdhdb.redomirrors[2]: 0 ; 0x0dc: 0x0000

kfdhdb.redomirrors[3]: 0 ; 0x0de: 0x0000

kfdhdb.dbcompat: 168820736 ; 0x0e0: 0x0a100000

kfdhdb.grpstmp.hi: 32939275 ; 0x0e4: HOUR=0xb DAYS=0x8 MNTH=0x7 YEAR=0x7da

kfdhdb.grpstmp.lo: 3712403456 ; 0x0e8: USEC=0x0 MSEC=0x1b2 SECS=0x14 MINS=0x37

kfdhdb.vfstart: 0 ; 0x0ec: 0x00000000

kfdhdb.vfend: 0 ; 0x0f0: 0x00000000

kfdhdb.spfile: 0 ; 0x0f4: 0x00000000

kfdhdb.spfflg: 0 ; 0x0f8: 0x00000000

kfdhdb.ub4spare[0]: 0 ; 0x0fc: 0x00000000

kfdhdb.ub4spare[1]: 0 ; 0x100: 0x00000000

kfdhdb.ub4spare[2]: 0 ; 0x104: 0x00000000

kfdhdb.ub4spare[3]: 0 ; 0x108: 0x00000000

kfdhdb.ub4spare[4]: 0 ; 0x10c: 0x00000000

kfdhdb.ub4spare[5]: 0 ; 0x110: 0x00000000

kfdhdb.ub4spare[6]: 0 ; 0x114: 0x00000000

kfdhdb.ub4spare[7]: 0 ; 0x118: 0x00000000

kfdhdb.ub4spare[8]: 0 ; 0x11c: 0x00000000

kfdhdb.ub4spare[9]: 0 ; 0x120: 0x00000000

kfdhdb.ub4spare[10]: 0 ; 0x124: 0x00000000

kfdhdb.ub4spare[11]: 0 ; 0x128: 0x00000000

kfdhdb.ub4spare[12]: 0 ; 0x12c: 0x00000000

kfdhdb.ub4spare[13]: 0 ; 0x130: 0x00000000

kfdhdb.ub4spare[14]: 0 ; 0x134: 0x00000000

kfdhdb.ub4spare[15]: 0 ; 0x138: 0x00000000

kfdhdb.ub4spare[16]: 0 ; 0x13c: 0x00000000

kfdhdb.ub4spare[17]: 0 ; 0x140: 0x00000000

kfdhdb.ub4spare[18]: 0 ; 0x144: 0x00000000

kfdhdb.ub4spare[19]: 0 ; 0x148: 0x00000000

kfdhdb.ub4spare[20]: 0 ; 0x14c: 0x00000000

kfdhdb.ub4spare[21]: 0 ; 0x150: 0x00000000

kfdhdb.ub4spare[22]: 0 ; 0x154: 0x00000000

kfdhdb.ub4spare[23]: 0 ; 0x158: 0x00000000

kfdhdb.ub4spare[24]: 0 ; 0x15c: 0x00000000

kfdhdb.ub4spare[25]: 0 ; 0x160: 0x00000000

kfdhdb.ub4spare[26]: 0 ; 0x164: 0x00000000

kfdhdb.ub4spare[27]: 0 ; 0x168: 0x00000000

kfdhdb.ub4spare[28]: 0 ; 0x16c: 0x00000000

kfdhdb.ub4spare[29]: 0 ; 0x170: 0x00000000

kfdhdb.ub4spare[30]: 0 ; 0x174: 0x00000000

kfdhdb.ub4spare[31]: 0 ; 0x178: 0x00000000

kfdhdb.ub4spare[32]: 0 ; 0x17c: 0x00000000

kfdhdb.ub4spare[33]: 0 ; 0x180: 0x00000000

kfdhdb.ub4spare[34]: 0 ; 0x184: 0x00000000

kfdhdb.ub4spare[35]: 0 ; 0x188: 0x00000000

kfdhdb.ub4spare[36]: 0 ; 0x18c: 0x00000000

kfdhdb.ub4spare[37]: 0 ; 0x190: 0x00000000

kfdhdb.ub4spare[38]: 0 ; 0x194: 0x00000000

kfdhdb.ub4spare[39]: 0 ; 0x198: 0x00000000

kfdhdb.ub4spare[40]: 0 ; 0x19c: 0x00000000

kfdhdb.ub4spare[41]: 0 ; 0x1a0: 0x00000000

kfdhdb.ub4spare[42]: 0 ; 0x1a4: 0x00000000

kfdhdb.ub4spare[43]: 0 ; 0x1a8: 0x00000000

kfdhdb.ub4spare[44]: 0 ; 0x1ac: 0x00000000

kfdhdb.ub4spare[45]: 0 ; 0x1b0: 0x00000000

kfdhdb.ub4spare[46]: 0 ; 0x1b4: 0x00000000

kfdhdb.ub4spare[47]: 0 ; 0x1b8: 0x00000000

kfdhdb.ub4spare[48]: 0 ; 0x1bc: 0x00000000

kfdhdb.ub4spare[49]: 0 ; 0x1c0: 0x00000000

kfdhdb.ub4spare[50]: 0 ; 0x1c4: 0x00000000

kfdhdb.ub4spare[51]: 0 ; 0x1c8: 0x00000000

kfdhdb.ub4spare[52]: 0 ; 0x1cc: 0x00000000

kfdhdb.ub4spare[53]: 0 ; 0x1d0: 0x00000000

kfdhdb.acdb.aba.seq: 0 ; 0x1d4: 0x00000000

kfdhdb.acdb.aba.blk: 0 ; 0x1d8: 0x00000000

kfdhdb.acdb.ents: 0 ; 0x1dc: 0x0000

kfdhdb.acdb.ub2spare: 0 ; 0x1de: 0x0000

從上面讀出的內容，我們可以獲取以下資訊:

dsknum 磁碟號

grptyp 磁碟所屬型別EXTERNAL REDUNDANCY,主要有以下三種型別

NORMAL REDUNDANCY - Two-way mirroring, requiring two failure groups.
HIGH REDUNDANCY - Three-way mirroring, requiring three failure groups.
EXTERNAL REDUNDANCY - No mirroring for disks that are already protected using hardware mirroring or RAID.

ddrsts 磁碟頭狀態

dskname 在asm中磁碟名

grpname 磁碟組名

fgname failure group name

crestmp.hi asm磁碟組建立時間

mntstmp.hi asm磁碟組mount時間

blksize 磁碟頭塊大小 4096

ausize 條帶化大小 4M

dsksize 磁碟大小

f1b1locn  File Directory blk 1 AU num

         Beginging for file directory

3.2 Md_backup備份

[grid@rac1 amdu_2010_07_08_15_15_18]$ asmcmd md_backup /home/grid/asmbk -G 'TESTDG'

Disk group metadata to be backed up: TESTDG

Current alias directory path: rac-cluster/OCRFILE

Current alias directory path: rac-cluster

Current alias directory path: rac-cluster/ASMPARAMETERFILE

3.3 模擬磁碟頭資訊丟失

[grid@rac1 ~]$ dd if=/dev/zero f=/dev/raw/raw1 bs=4096 count=1

1+0 records in

1+0 records out

4096 bytes (4.1 kB) copied, 0.016114 seconds, 254 kB/s

[grid@rac1 ~]$ kfed read /dev/raw/raw1

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: T=0 NUMB=0x0

kfbh.block.obj: 0 ; 0x008: TYPE=0x0 NUMB=0x0

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

ERROR!!!, failed to get the oracore error message

這時磁碟組testdg下/dev/raw/raw1磁碟頭資訊丟失，不能正常讀取。

SQL> alter diskgroup testdg dismount;

Diskgroup altered.

SQL> alter diskgroup testdg mount;

alter diskgroup testdg mount

*

ERROR at line 1:

ORA-15032: not all alterations performed

ORA-15017: diskgroup "TESTDG" cannot be mounted

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

"TESTDG"

可以看到testdg不能正常提供對外訪問。

3.4 md_restore命令恢復磁碟組後設資料

3.4.1 所有節點把testdg 服務offline

Srvctl stop diskgroup –g testdg

否則恢復時會報ORA-15030錯誤

[grid@rac1 ~]$ asmcmd md_restore /home/grid/asmbk.txt --silent -G 'testdg'

Current Diskgroup metadata being restored: TESTDG

ASMCMD-09352: CREATE DISKGROUP failed

ORA-15018: diskgroup cannot be created

ORA-15030: diskgroup name "TESTDG" is in use by another diskgroup (DBD ERROR: OCIStmtExecute)

3.4.2 恢復磁碟組後設資料庫

[grid@rac1 ~]$ asmcmd md_restore /home/grid/asmbk --silent -G 'testdg'

Current Diskgroup metadata being restored: TESTDG

Diskgroup TESTDG created!

System template ONLINELOG modified!

System template AUTOBACKUP modified!

System template ASMPARAMETERFILE modified!

System template OCRFILE modified!

System template ASM_STALE modified!

System template OCRBACKUP modified!

System template PARAMETERFILE modified!

System template ASMPARAMETERBAKFILE modified!

System template FLASHFILE modified!

System template XTRANSPORT modified!

System template DATAGUARDCONFIG modified!

System template TEMPFILE modified!

System template ARCHIVELOG modified!

System template CONTROLFILE modified!

System template DUMPSET modified!

System template BACKUPSET modified!

System template FLASHBACK modified!

System template DATAFILE modified!

System template CHANGETRACKING modified!

[grid@rac1 ~]$

3.4.3 所有節點包testdg服務online

[grid@rac1 ~]$ srvctl start diskgroup -g testdg

[grid@rac1 ~]$ sqlplus "/as sysasm"

SQL*Plus: Release 11.2.0.1.0 Production on Thu Jul 8 16:43:53 2010