information on SCSI Sense Key Error

ense Key Error Format

A SCSI sense key error is formatted as follows:

Sense Key = 0x1, Asc = 0x18, Ascq = 0x2

Sense Data Description = Recovered Data - Data Auto-Reallocated

Asc stands for Additional Sense Code

Ascq stands for Additional Sense Code Qualifiers

Sense Key = 0x1 Errors

All 0x1 sense key errors indicate that the command was completed successfully,

with some recovery action performed by the disk. When multiple recovered errors

occur, the last error that occurred is reported by the additional sense bytes. All 0x1

sense keys are soft errors and proactive replacement is normally not required.

TABLE 1 Sense Key = 0x1 Errors

Asc Ascq Error Message Description

0x3 0x0 Peripheral Device Write Fault

A soft recoverable error that is typically seen in transient environmental conditions, such as vibration or shock. This condition is corrected after another write to the same disk sector is completed (assuming that the environmental condition is not sustained).

0x9 0x0 Track Following

Error

A result of the disk head not following the data track on the disk media. This condition is normally corrected during the next write operation on the track.

0x9 0x1 Write Fault

Status During Read (Tracking

Servo Failure) Indicates that the disk servo failed to allocate the disk head to the correct data track before the write operation. The disk servo corrects this condition by reallocating the disk head to the correct data track.

0xc 0x1 Write Error

Recovered With Auto Reallocation Indicates that a write error occurred on the drive,

but it was recovered and data was reallocated. Normally, if the feedback signal from the drive write head is not strong, the drive reallocates the data to a spare sector.

0x15 0x1 Mechanical

Positioning Error A transient condition. The drive “knows” that the head is not where it is supposed to be, makes the proper adjustments, and reads or writes the data during the next rotation. The drive has logic to continuously resync itself.

0x17 0x1 Recovered Data With Retries

See 0x17/0x3.

0x17 0x2 Recovered Data With PositiveHead Offset See 0x17/0x3.

SCSI Sense Key Error Guide 3

0x17 0x3 Recovered Data

With Negative Head Offset

A result of a read exception condition. It indicates that the drive was able to recover the data using the normal number of retries.

0x17 0x8 Recovered Data

w/o ECC Recommend Rewrite

A result of a read exception condition. It indicates that the data was recovered but rewrite is recommended.

0x18 0x1 Recovered Data

Using ECC After Normal Retries

A read condition that indicates that the drive was able to recover the data using the normal number of retries.

0x18 0x2 Recovered Data

- Data Auto-Reallocated

A read condition that indicates that the drive was able to recover the data by reallocating the sector.

0x5d 0x0 Failure

Prediction Threshold Exceeded

Indicates that the drive reached its failure prediction threshold and it is necessary to replace the disk (after the data is transferred to a standby disk, if one is available).

TABLE 1 Sense Key = 0x1 Errors (Continued)

Asc Ascq Error Message Description

Sense Key = 0x2 Errors

All 0x2 sense key errors indicate that the drive is not in a ready state and cannot be

accessed.

TABLE 2 Sense Key = 0x2 Errors

Asc Ascq Error Message Description

0x4 0x1 Logical Unit

Not Ready, Becoming Ready Indicates that the drive is OK— it is in the process of spinning up, but it is not yet ready.

0x4 0x2 Logical Unit

Not Ready, Init. Cmd Required

Indicates that the drive is ready to go, but it is not spinning. Generally, the drive needs to be spun up.

0x4 0x3 Logical Unit

Not Ready, Manual Intervention is Required

Requires manual intervention—the recommended action is to reseat the drive

SCSI Sense Key Error Guide 5

Sense Key = 0x3 Errors

All 0x3 sense key errors indicate that the command terminated with an unrecovered

error condition.

TABLE 3 Sense Key = 0x3 Errors

Asc Ascq Error Message Description

0x11 0x0 Unrecovered Read Error

The RAID controller firmware, during a normal read or volumes verification operation, corrects the bad sector on the drive by reconstructing the data (assuming a RAID 1+0 or RAID 5 configuration) and writing it back to the drive.

The drive, in turn, writes the data to a spare sector. Ensure that the volume is scrubbed on a regular basis. If the volumes in the RAID device are configured as RAID0, then the data is lost and drive replacement is required.

0x11 0x1 Read Retries

Exhausted

0x11 0x2 Unrecovered error was detected during Data Read (BCRC error detected by SCSI)

0x11 0x4 Unrecovered

Read Error, Auto Reallocation Failed

0x16 0x0 Data Synchronization

Mark Missing Or Incorrect.This error requires a disk replacement, regardless of the RAID level. This condition is fatal, where the track is lost and the RAID device will disable the disk.

Sense Key = 0x4 Errors

All 0x4 sense key errors indicate that the disk drive detected an unrecoverable

hardware failure while performing the command or during a self-test. Replace a

drive when this type of error occurs.

TABLE 4 Sense Key = 0x4 Errors

Asc Ascq Error Message

0x15 0x1 Mechanical Positioning Error

0x15 0x2 Positioning Error Detected by Read of Media

0x32 0x0 Not Defect Spare Sectors Available

0x32 0x1 Defect List (G) Update Failure

0x3E 0x3 Logic Unit Failed Self-Test

0x3E 0x4 Logic Unit Unable to

update Self-Test Result Log

SCSI Sense Key Error Guide 7

Sense Key = 0x5 Errors

All 0x5 sense key errors are information errors. The 0x5 sense key is a host/RAID

controller interaction sense key. This key’s errors indicate that the RAID controller

received an illegal request from the host. In some cases, the host is sending out a

command, asking an individual drive to perform a read or write operation.

However, the problem is that no host can communicate directly to the individual

drives in a hardware RAID device. The host can only communicate with the RAID

controller. In this case, the RAID controller is returning an illegal request statement

back to the host, stating that it doesn't understand what the host is asking.

For 0x5 sense key errors, no corrective action is required to the disk. When you see

this error, send the sense key log to a specialist for help.

TABLE 5 Sense Key = 0x5 Errors

Asc Ascq Error Message

0x25 0x0 Logical Unit Number Not supported

0x26 0x97 Invalid Field Parameter – TMS Firmware Tag

0x26 0x99 Invalid Field Parameter - Firmware Tag

Sense Key = 0xb Errors

All 0xb sense key errors indicate that the disk drive aborted the command and that

the initiator may be able to recover by trying the command again.

TABLE 6 Sense Key = 0xb Errors

Asc Ascq Error Message Description

0x45 0x0 Select/Reselect failure

0x47 0x0 SCSI Parity Error

This error implies that a parity error condition occurred on the disk. This means that the disk has not received the FC packet correctly. The possibile causes of a parity error condition include:

1. The FC interface chip on one of the disks has gone bad, resulting in FC frames being

corrupted (for example, a frame size error).

2. An internal circuit on one of the drives has gone bad, resulting in the drive not being able to sendor receive FC frames correctly. In this situation, the drive receives data that does not match the parity bit. The data is rejected and

an error is generated.

3. Some other component on the FC loop is contributing to the noise on the loop, resulting in this error. It is difficult to identify the failing component when a 0x47/0x0 error is found, because any component on the FC loop might be the cause. Consult a specialist for help when this error is seen.

Note also that a 0x47/0x0 error may occur on the host side of an array—that is, any component on the FC loop on the host side may be causing the problem. In this situation, consult a specialist for help in identifying the failing component.