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标题:使用asm disk header 自动备份信息恢复异常asm disk header
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.]
通过参考kamus的Where is the backup of ASM disk header block,发现从10.2.0.5开始的asm确实存在自动备份asm disk header功能.有了这个功能对于那些不备份asm disk header的同学,提供了一层保证,也增加了asm的安全性.
对于10.2.0.5.0以及以后版本,不管au size是多少,asm disk header自动备份存储的位置是第2个au的倒数第2个block.
计算方法:AU中包含的block num[AU_SIZE/block_size]*2-2[因为从第一个块从0计数],通过该方法计算结论为:
1M AU在510
2M AU在1022
4M AU在2046
8M AU在4094
16M AU在8190
32M AU在16382
64M AU在32766
1.对比备份asm disk header
SQL> select * from v$version; BANNER ---------------------------------------------------------------- Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - Prod PL/SQL Release 10.2.0.5.0 - Production CORE 10.2.0.5.0 Production TNS for Linux: Version 10.2.0.5.0 - Production NLSRTL Version 10.2.0.5.0 - Production SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') "xifenfei.com" from dual; xifenfei.com ------------------- 2012-06-17 09:41:19 SQL> select group_number,DISK_NUMBER,PATH,HEADER_STATUS 2 from v$asm_disk where group_number<>0; GROUP_NUMBER DISK_NUMBER PATH HEADER_STATU ------------ ----------- --------------- ------------ 1 1 /dev/raw/raw2 MEMBER 1 0 /dev/raw/raw1 MEMBER SQL> select group_number,name,BLOCK_SIZE,ALLOCATION_UNIT_SIZE from v$asm_diskgroup; GROUP_NUMBER NAME BLOCK_SIZE ALLOCATION_UNIT_SIZE ------------ ------------------------------ ---------- -------------------- 1 DATA 4096 1048576 rac1-> kfed read /dev/raw/raw1 blknum=510|>/tmp/xifenfei.510 rac1-> kfed read /dev/raw/raw1 blknum=0|>/tmp/xifenfei.0 rac1-> ll /tmp/xifenfei* -rw-r--r-- 1 oracle oinstall 6606 Jun 14 04:11 /tmp/xifenfei.0 -rw-r--r-- 1 oracle oinstall 6606 Jun 14 04:12 /tmp/xifenfei.510 rac1-> diff /tmp/xifenfei.510 /tmp/xifenfei.0 --通过对比发现两者无不同记录返回,证明他们记录内容完全相同
2.尝试破坏asm disk header
rac1-> dd if=/dev/zero of=/dev/raw/raw1 bs=4096 count=1 1+0 records in 1+0 records out rac1-> kfed read /dev/raw/raw1 blknum=0 kfbh.endian: 0 ; 0x000: 0x00 kfbh.hard: 0 ; 0x001: 0x00 kfbh.type: 0 ; 0x002: KFBTYP_INVALID kfbh.datfmt: 0 ; 0x003: 0x00 kfbh.block.blk: 0 ; 0x004: T=0 NUMB=0x0 kfbh.block.obj: 0 ; 0x008: TYPE=0x0 NUMB=0x0 kfbh.check: 0 ; 0x00c: 0x00000000 kfbh.fcn.base: 0 ; 0x010: 0x00000000 kfbh.fcn.wrap: 0 ; 0x014: 0x00000000 kfbh.spare1: 0 ; 0x018: 0x00000000 kfbh.spare2: 0 ; 0x01c: 0x00000000 SQL> select group_number,DISK_NUMBER,PATH,HEADER_STATUS 2 from v$asm_disk where group_number<>0; GROUP_NUMBER DISK_NUMBER PATH HEADER_STATU ------------ ----------- --------------- ------------ 1 1 /dev/raw/raw2 MEMBER 1 0 /dev/raw/raw1 CANDIDATE SQL> alter diskgroup data dismount; Diskgroup altered. SQL> alter diskgroup data mount; alter diskgroup data mount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15063: ASM discovered an insufficient number of disks for diskgroup "DATA"
3.使用kfed repair修改损坏asm disk header
rac1-> kfed repair '/dev/raw/raw1' rac1-> kfed read /dev/raw/raw1 blknum=0 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: 883602253 ; 0x00c: 0x34aab34d kfbh.fcn.base: 0 ; 0x010: 0x00000000 kfbh.fcn.wrap: 0 ; 0x014: 0x00000000 kfbh.spare1: 0 ; 0x018: 0x00000000 kfbh.spare2: 0 ; 0x01c: 0x00000000 ………… SQL> alter diskgroup data mount; Diskgroup altered.
4.使用kfed merge恢复asm disk header
rac1-> dd if=/dev/zero of=/dev/raw/raw1 bs=4096 count=1 1+0 records in 1+0 records out rac1-> kfed read /dev/raw/raw1 blknum=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: 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 SQL> alter diskgroup data dismount; Diskgroup altered. SQL> alter diskgroup data mount; alter diskgroup data mount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15063: ASM discovered an insufficient number of disks for diskgroup "DATA" rac1-> kfed merge /dev/raw/raw1 /tmp/xifenfei.510 SQL> alter diskgroup data mount; Diskgroup altered.
通过试验证明在10.2.0.5及其以后版本中,对于备份的asm disk header我们可以通过使用kfed repair和kfed merge来恢复.
10.2.0.1 asm 中无此项备份
编译kfed程序