ASM DISK HEADER Backup and recovery in Oracle

Recently encountered a number of ASM data header problems caused disk GROUP can not be normal mount, the database is not working properly, has brought endless trouble, this time thinking, if I did the ASM data header backup How good ah, unfortunately there is no regret medicine, We recommend that you check your own ASM library, ASM HEADER has done a backup, if not please handle it in time. Here the test provides DD and kfed backup and restore ASM headers

Query ASM Related Information

Sql> select Group_number,name,state,total_mb,free_mb from V$asm_diskgroup;

Group_number NAME State TOTAL_MB FREE_MB

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

1 DATA Mounted 2046 1314

2 Xifenfei mounted 6141 4378

Sql> select Group_number,disk_number,path,state from V$asm_disk;

Group_number Disk_number PATH State

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

1 1/dev/oracleasm/disks/vol2 NORMAL

1 0/dev/oracleasm/disks/vol1 NORMAL

2 1/dev/oracleasm/disks/vol4 NORMAL

2 0/dev/oracleasm/disks/vol3 NORMAL

Find the ASM disk corresponding to the partition

[Grid@rac1 ~]$/etc/init.d/oracleasm querydisk-d VOL1

Disk "VOL1" is a valid ASM disk on device [8,33]

[Grid@rac1 ~]$ Ll/dev |grep 8|grep 33

Brw-r-----1 Root disk 8, APR 11:37 SDC1

[Grid@rac1 ~]$/etc/init.d/oracleasm querydisk-d VOL2

Disk "VOL2" is a valid ASM disk on device [8,34]

[Grid@rac1 ~]$ Ll/dev |grep 8|grep 34

Brw-r-----1 Root disk 8, APR 11:37 SDC2

[Grid@rac1 ~]$/etc/init.d/oracleasm querydisk-d VOL3

Disk "VOL3" is a valid ASM disk on device [8,17]

[Grid@rac1 ~]$ ll/dev |grep 8,|grep 17

Brw-r-----1 Root disk 8, APR 11:37 SDB1

[Grid@rac1 ~]$/etc/init.d/oracleasm querydisk-d VOL4

Disk "VOL4" is a valid ASM disk on device [8,18]

[Grid@rac1 ~]$ Ll/dev |grep 8,|grep 18

Brw-r-----1 Root disk 8, APR 11:37 SDB2

Back Up ASM header information (Backup Xifenfei disk group)

--DD Mode Backup

[Root@rac1 backup_asmheader]# dd if=/dev/sdb1 of=vol3header.dd bs=4096 count=1

1+0 Records in

1+0 Records out

4096 bytes (4.1 kB) copied, 0.000143581 seconds, 28.5 MB/s

[Root@rac1 backup_asmheader]# dd if=/dev/sdb2 of=vol4header.dd bs=4096 count=1

1+0 Records in

1+0 Records out

4096 bytes (4.1 kB) copied, 0.000147727 seconds, 27.7 MB/s

--kfed Mode Backup

[Grid@rac1 backup_asmheader]$ kfed read/dev/oracleasm/disks/vol3 text=vol3header.txt

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[Grid@rac1 backup_asmheader]$ more Vol3header.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:blk=0

kfbh.block.obj:2147483648; 0x008:disk=0

kfbh.check:198826195; 0x00c:0x0bd9d8d3

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:ORCLDISKVOL3; 0x000:length=12

Kfdhdb.driver.reserved[0]: 860639062; 0x008:0x334c4f56

KFDHDB.DRIVER.RESERVED[1]: 0; 0x00c:0x00000000