Certain VMkernel messages related to storage might contain SCSI Sense codes.
When you analyze ESXi host's /var/log/vmkernel log files, you encounter events or error messages that contain SCSI Sense codes.
Example: Interpreting SCSI Sense Codes
2011-04-04T21:07:30.257Z cpu2:2050)ScsiDeviceIO: 2315: Cmd(0x4124003edb00) 0x12, CmdSN 0x51 to dev "naa.600508XXXXXXXXXXXXX" failed H:0x0 D:0x2 P:0x0 Valid sense data: 0x5 0x25 0x0In this example, SCSI Sense codes are represented by two fields, H:0x0 D:0x2 P:0x0 and 0x5 0x25 0x0.
The first field, H:0x0 D:0x2 P:0x0, is a combination of SCSI Status codes for the three components in your storage environment, the host, the device, and the plug-in. The SCSI Status code is used to determine the success or failure of a SCSI command. To interpret each SCSI Status code, see the http://www.t10.org/lists/2status.htm.
The second field in a typical SCSI error message provides more detailed information about the error. It is a combination of Sense Key (sense), Additional Sense Code (asc), and Additional Sense Code Qualifier (ascq) parameters.
For example, the 0x5 0x25 0x0 field from the above error message can be represented as sense=5 asc=25 ascq=0.
To interpret Sense Keys, see http://www.t10.org/lists/2sensekey.htm.
To determine the meaning of the Additional Sense Code (asc) and Additional Sense Code Qualifier (ascq), use the two codes together. See http://www.t10.org/lists/2asc.htm for details.
You should get the following interpretation for the 0x5 0x25 0x0 field:
sense=5 (ILLEGAL REQUEST), ASC=25 ASCQ=0 (LOGICAL UNIT NOT SUPPORTED)