Wipe out and reuse ASM disk header !
Grid installation fails due to issues to execute root.sh scripts on both nodes
It is always a challenge,if the installation get failed at half of progress and there is no other option that we have to reinstall grid because of ignorance of failed prerequisites
[root@rac1 grid]# /apps01/home/12.1.0/grid/bin/kfod status=TRUE asm_diskstring='/dev/oracleasm/asm*' disks=all dscvgroup=TRUE
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ORACLE_SID ORACLE_HOME
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+ASM1 /apps01/home/12.1.0/grid
[root@rac1 grid]# /apps01/home/12.1.0/grid/bin/kfod status=TRUE asm_diskstring='/dev/oracleasm/disks/*' disks=all dscvgroup=TRUE
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Disk Size Header Path Disk Group User Group
================================================================================
1: 12284 Mb CANDIDATE /dev/oracleasm/disks/DATA # oracle oinstall
2: 12284 Mb CANDIDATE /dev/oracleasm/disks/FRA # oracle oinstall
3: 6142 Mb MEMBER /dev/oracleasm/disks/OCR OCR oracle oinstall
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ORACLE_SID ORACLE_HOME
================================================================================
+ASM1 /apps01/home/12.1.0/grid
Read the disk header to check the validity of the disk
[root@rac1 grid]# /apps01/home/12.1.0/grid/bin/kfed read /dev/oracleasm/disks/OCR AUNUM=0 BLKNUM=0
kfbh.endian: 1 ; 0x000: 0x01
kfbh.hard: 130 ; 0x001: 0x82
kfbh.type: 1 ; 0x002: KFBTYP_DISKHEAD <<<<====
clear the asm disk header using dd
[root@rac1 grid]# dd if=/dev/zero of=/dev/oracleasm/disks/DATA bs=8192 count=128 00
12800+0 records in
12800+0 records out
104857600 bytes (105 MB) copied, 3.36437 s, 31.2 MB/s
[root@rac1 grid]# dd if=/dev/zero of=/dev/oracleasm/disks/FRA bs=8192 count=1280 0
12800+0 records in
12800+0 records out
104857600 bytes (105 MB) copied, 2.39119 s, 43.9 MB/s
[root@rac1 grid]# dd if=/dev/zero of=/dev/oracleasm/disks/OCR bs=8192 count=1280 0
12800+0 records in
12800+0 records out
104857600 bytes (105 MB) copied, 0.0719423 s, 1.5 GB/s
Query the disks if their headers are marked
[root@rac1 grid]# oracleasm querydisk DATA
Disk "DATA" defines an unmarked device
[root@rac1 grid]# oracleasm querydisk FRA
Disk "FRA" defines an unmarked device
[root@rac1 grid]# oracleasm querydisk OCR
Disk "OCR" defines an unmarked device
Read the header and the KFBTYP should be invalid !
[root@rac1 grid]# /apps01/home/12.1.0/grid/bin/kfed read /dev/oracleasm/disks/OCR AUNUM=0 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: 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
000000000 00000000 00000000 00000000 00000000 [................]
Repeat 255 times
KFED-00322: file not found; arguments: [kfbtTraverseBlock] [Invalid OSM block type] [] [0]
The asm disk headers are cleared.Now we are good to reuse the asm disks for new installation of grid