Intel RAID Controllers Alert Code Decoding White Paper

Decoding Intel® RAID Sense Code Messages Intel® RAID Controllers: SAS Software Stack

Revision 1.0

1. Decoding Intel® RAID Sense Code Messages

1.1 Purpose

This document reviews unexpected sense codes returned by SAS/SATA RAID devices attached

to an Intel

RAID Controller using the SAS software stack. This document does not describe all

error types or messages generated by these RAID Controllers.

1.2 RAID Logs

The RAID controller error events are logged as they occur. The type of RAID controller

determines where and when the events are logged, and the RAID application determines what

portion of the log entries can be viewed.

 Intel

SAS/SATA Hardware based RAID Controllers (solutions utilizing an I/O processor)

persistently log error events in an NVRAM log. Events are logged from the point of

power on, including out-of-band events (events that occur when the operating system is

not yet loaded or is not operational). Text for these logged errors can be viewed in RAID

BIOS Console or RAID Web Console2; or the text can be extracted using the command

line utility.

 Intel

SAS/SATA Software based RAID Controllers (solutions that do not utilize an I/O

processor) log error events only in the RAID Web Console2 log, and do not have

NVRAM available to persistently save error messages. Events are only logged when the

RAID Web Console2 application is running within the operating system. These error

events can be viewed only in RAID Web Console2.

1.3 RAID Log Events

Logged events include status change events, informational messages and error messages.

Unexpected Sense Codes are error messages that are generated when a device attached to a

RAID controller encounters an error and responds with a device based error message. These

messages are based on the industry standard T10 technical committee SCSI ASC/ASCQ

assignments (refer to http://www.t10.org/lists/asc-num.txt

for more information). A copy of this

reference list is in Appendix A.

The sequence of events that can lead to an unexpected sense code error message is listed

below.

1. The host adapter issues a command and receives a status update.

2. The RAID controller will issue a REQUEST SENSE command to the device if the status

is other than GOOD (00h). Usually the error status inquiry is CHECK CONDITION (02h).

3. The REQUEST SENSE response from the device is the unexpected sense code and

consists of the Command Data Block (CDB) issued by the host device and the Sense

data from the target device.

4. The CDB contains the command sent to the device. The sense data contains the error

message sent from the device and includes up to 255 bytes of information. The first 17

bytes are mandatory and all other bytes are optional additional sense bytes. The first 17

bytes contain the Error Code, Sense Key, the Additional Sense Code and the Additional