ORA-27063: number of bytes read/written is incorrect

Applies to:

Oracle Database - Enterprise Edition - Version 8.1.6.0 to 11.2.0.0 [Release 8.1.6 to 11.2]
Information in this document applies to any platform.
***Checked for relevance on 07-Oct-2011***

Symptoms

Database may crash due to I/O errors depending on the file that reports the error, such as the controlfile.

Alert log may report messages like these:

ORA-00206: error in writing (block 3, # blocks 1) of control file
ORA-00202: control file: '/u04/oradata/symprd/control03.ctl'
ORA-27063: number of bytes read/written is incorrect
SVR4 Error: 5: I/O error
Additional information: -1
Additional information: 16384

 OR

ORA-00345: redo log write error block 24041 count 2
ORA-00312: online log 5 thread 1: '/oradata/bjfhcat/redo05.log'
ORA-27063: number of bytes read/written is incorrect
IBM AIX RISC System/6000 Error: 5: I/O error
Additional information: -1
Additional information: 1024

OR

ORA-01114: IO error writing block to file 3021 (block # 72721)
ORA-27063: skgfospo: number of bytes read/written is incorrect
SVR4 Error: 5: I/O error
Additional information: -1
Additional information: 258048

OR

Errors in file /oracle/product/diag/asm/+asm/+ASM1/trace/+ASM1_ora_21814.trc:
ORA-27063: number of bytes read/written is incorrect
SVR4 Error: 5: I/O error
Additional information: -1
Additional information: 1048576
WARNING: Write Failed. group:2 disk:6 AU:262074 offset:0 size:1048576
Errors in file /oracle/product/diag/asm/+asm/+ASM1/trace/+ASM1_ora_21814.trc:
ORA-27063: number of bytes read/written is incorrect
SVR4 Error: 5: I/O error
Additional information: -1
Additional information: 1048576

OR

ORA-01115: IO error reading block from file 397 (block # 8633)
ORA-01110: data file 397: '/u04/flexpm/traffic_medium26.dbf'
ORA-27063: number of bytes read/written is incorrect
SVR4 Error: 5: I/O error
Additional information: -1
Additional information: 16384

OR

ORA-27063: number of bytes read/written is incorrect
SVR4 Error: 5: I/O error
Additional information: -1
Additional information: 1048576
WARNING: Write Failed. group:2 disk:1 AU:646 offset:0 size:1048576
path:/dev/rdsk/c10t60060E8005BCE5000000BCE500000243d0s0
incarnation:0xf0f46246 asynchronous result:'I/O error'
subsys:System iop:0xffffffff78841f40 bufp:0xffffffff774bf000 osderr:0x0 osderr1:0x0
ORA-15080: synchronous I/O operation to a disk failed
WARNING: failed to write mirror side 1 of virtual extent 32 logical extent 0 of file 2390 in group 2 on disk 1 allocation unit 646
*** yyyy-mm-dd hh24:mi:ss.sss 4320 krsh.c
ARC5: Encountered disk I/O error 19502

 

Cause

This is due to a problem with the I/O subsystem.

Issues of this nature are common when there is a problem in the I/O subsystem.
This can include, but is not limited to:

• A bad sector on disk
• An I/O card that is starting to fail
• A bad array cable
• An interruption in network connectivity, in the case of NFS mounts
• Could also be caused by a OS level bug.
• etc.

Review the OS Messages file as this will almost certainly reflect errors (for example  Error for Command: write(10) )

Solution

Open a ticket with the disk hardware vendor to

• run diagnostics on the disk where the problematic file resides and
• investigate / resolve the cause of the I/O error

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