Originally posted by: SystemAdmin

Hello Everyone,
I've a LPAR with 8 Hitachi disks, out of which only one disk is generating frequent SC_DISK_ERR4 DCB47997- DISK OPERATION ERROR disk operation errors in the host.

DCB47997 0221173013 T H hdisk6 DISK OPERATION ERROR
DCB47997 0221173013 T H hdisk6 DISK OPERATION ERROR
DCB47997 0221173013 T H hdisk6 DISK OPERATION ERROR
DCB47997 0221173013 T H hdisk6 DISK OPERATION ERROR
.
.
.
. output truncated

From SAN end, I dont see any errors/abnormalities. I mean to say, zoning is fine & LUN is presented properly to the LPAR. Also, the disk is not shared to any of other LPARs.
Could someone please help me in fixing this problem.????? What could be the possible reasons of these errors in only disk, not in any other.

Thanks,
Rakesh
#AIX-Forum

Originally posted by: dukessd

Posting the whole error might give us a better start.
#AIX-Forum

Originally posted by: SystemAdmin

Hello Duke,
Please find the whole error description. would this be enough???? :)

LABEL: SC_DISK_ERR4
IDENTIFIER: DCB47997

Date/Time: Thu Feb 21 17:31:21 CUT 2013
Sequence Number: 190411
Machine Id: 00C3DAFE4C00
Node Id: Host1
Class: H
Type: TEMP
WPAR: Global
Resource Name: hdisk6
Resource Class: disk
Resource Type: Hitachi
Location: U788C.001.AAA8266-P1-C14-C2-T1-W50060E801603171F-L0

VPD:
Manufacturer................HITACHI
Machine Type and Model......OPEN-V
Part Number.................
ROS Level and ID............37303033
Serial Number...............50 10317
EC Level....................
FRU Number..................
Device Specific.(Z0)........00000332EF000002
Device Specific.(Z1)........6186 5H ....
Device Specific.(Z2)..........aa
Device Specific.(Z3).........
Device Specific.(Z4).........Nq.
Device Specific.(Z5)........
Device Specific.(Z6)........

Description
DISK OPERATION ERROR

Probable Causes
MEDIA
DASD DEVICE

User Causes
MEDIA DEFECTIVE

Recommended Actions
FOR REMOVABLE MEDIA, CHANGE MEDIA AND RETRY
PERFORM PROBLEM DETERMINATION PROCEDURES

Failure Causes
MEDIA
DISK DRIVE

Recommended Actions
FOR REMOVABLE MEDIA, CHANGE MEDIA AND RETRY
PERFORM PROBLEM DETERMINATION PROCEDURES

Detail Data
PATH ID
2
SENSE DATA
0A00 2800 0000 0980 0002 0004 0000 0000 0000 0000 0000 0000 0200 0300 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0014 26F4 0004 3F00 0000 0000 0000 0000 0000 0000 0000 0005 0000
0000 0035 001D

Thanks,
#AIX-Forum

Originally posted by: dukessd

The following redbook can help you understand these errors.

http://publib.boulder.ibm.com/systems/hardware_docs/pdf/234329.pdf

Page 89 shows how to understand some of the sense data, obviously in the one you posted there is a problem with path 2, are the others the same path or other paths?

The sense data shows:
VV = 02: Indicates that the Adapter Status field (AA) is valid
AA = 03: Command Timeout. This indicates that the SCSI command did not
complete within the allowed time. This usually indicates a hardware
problem related to the SCSI transport layer

This suggests AIX sent a command to hdisk6 but the command timed out.

If there are no errors to indicate a transport problem, fca_err / fcs_err / fcp_err / fscsi_err, then this is likely an end device problem and you need to take it up with Hitachi.

There are also a few APARs relating to this type of error, for instance:
http://www-01.ibm.com/support/docview.wss?uid=isg1IZ92300

HTH
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