Zeroed ASM blocks
(Doc ID 1997517.1)
Last updated on DECEMBER 23, 2019
Applies to:
Oracle Database - Enterprise Edition - Version 11.2.0.2 to 12.1.0.2 [Release 11.2 to 12.1]Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.
Symptoms
1. ASM reports one or several corrupted blocks in the alert log file, laong with the error ORA-15196:
WARNING: cache read a corrupt block: group=1(<DISKGROUP>) dsk=0 blk=1 disk=0 (<DISK>) incarn=3916383599 au=0 blk=1 count=1
Errors in file <trace file>
ORA-15196: invalid ASM block header [kfc.c:26076] [endian_kfbh] [2147483648] [1] [0 != 1]
NOTE: a corrupted block from group CRSDG was dumped to <trace file>
2. AMDU reports metadata corrupted blocks in the file report.txt:
Allocated AU's: 253711
Free AU's: 145649
AU's read for dump: 15
Block images saved: 1273
Map lines written: 15
Heartbeats seen: 0
Corrupt metadata blocks: 768 ------> HERE
Corrupt AT blocks: 2 ------> HERE
3. kfed reveals the blocks, several of them are zeroes:
$kfed read <disk1> aunum=0 blknum=1
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
2B98D2EFF400 00000000 00000000 00000000 00000000 [................]
Repeat 255 times
$kfed read <disk2> aunum=0 blknum=2
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
2B2D30FBB400 00000000 00000000 00000000 00000000 [................]
Repeat 255 times
$kfed read <disk3> aunum=0 blknum=3
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
2B9D91687400 00000000 00000000 00000000 00000000 [................]
Repeat 255 times
The output shown above was collected from different disks, which belong to different diskgroups. Development found blocks 1,2,3 and 4 were all zeroes.
Cause
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In this Document
| Symptoms |
| Cause |
| Solution |