Knowledge Base

Note: This document is only for informational purposes. It does not reflect an issue with any VMware product.

SCSI status codes recorded in the ESX logs indicates I/O has failed with a given status. This condition may be temporary, transient, benign or fatal for any given workload depending on the status received. The meaning of the status should be determined by consulting the T10 standards documentation. Some SCSI status codes, when received by an ESX host, prompt path failover. For more information, see SCSI events that can trigger ESX server to fail a LUN over to another path (1003433)

Isolate the SCSI events, and focus on the hexadeximal values:

0/8 0x0 0x0 0x0
H:0x8 D:0x0 P:0x0 Possible sense data: 0x0 0x0 0x0

Use the legend and links below to decipher the status of the host and devices during the SCSI event:

• SCSI Host Codes
  
  These codes potentially come from the firmware on a host adapter or from one of several hosts that an adapter driver controls. The 'host_status' field has the following values whose #defines mimic those which are only visible within the kernel (with the "SG_ERR_" removed from the front of each define). A copy of these defines can be found in sg_err.h (see Appendix A):
  
  SG_ERR_DID_OK [0x00] NO error
  
  SG_ERR_DID_NO_CONNECT [0x01] Couldn't connect before timeout period
  
  SG_ERR_DID_BUS_BUSY [0x02] BUS stayed busy through time out period
  
  SG_ERR_DID_TIME_OUT [0x03] TIMED OUT for other reason (often this an unexpected device selection timeout)
  
  SG_ERR_DID_BAD_TARGET [0x04] BAD target, device not responding?
  
  SG_ERR_DID_ABORT [0x05] Told to abort for some other reason.
  
  SG_ERR_DID_PARITY [0x06] Parity error. Older SCSI parallel buses have a parity bit for error detection. This probably indicates a cable or termination problem.
  
  SG_ERR_DID_ERROR [0x07] Internal error detected in the host adapter.
  
  SG_ERR_DID_RESET [0x08] The SCSI bus (or this device) has been reset. Any SCSI device on a SCSI bus is capable of instigating a reset.
  
  SG_ERR_DID_BAD_INTR [0x09] Got an interrupt we weren't expecting
  
  SG_ERR_DID_PASSTHROUGH [0x0a] Force command past mid-layer
  
  SG_ERR_DID_SOFT_ERROR [0x0b] The low level driver wants a retry
  
  For more information, see http://tldp.org/HOWTO/SCSI-Generic-HOWTO/x291.html.
  
  For additional information on SCSI host codes refer to Understanding SCSI host-side NMP errors/conditions in ESX 4.x (1029039)
  
  
  
• SCSI Device/Status Codes
  
  SCSI Status codes appear in the Status byte returned when processing of a command completes. The Code values are assigned by the T10 committee. The information on this page was accurate as of 20 August 2007. Do not be concerned if this date looks old. The Status code assignments change very infrequently. For more information on Status codes consult the latest revision of SAM-x.
  
  Code Name
  
  00h GOOD
  
  02h CHECK CONDITION
  
  04h CONDITION MET
  
  08h BUSY
  
  18h RESERVATION CONFLICT
  
  28h TASK SET FULL
  
  30h ACA ACTIVE
  
  40h TASK ABORTED
  
  
  For more information, see http://www.t10.org/lists/2status.htm.
  Note: Hexadecimal numbers in the T10 documentation use the NNNh notation, whereas SCSI status codes logged to the ESX host use the equivalent 0xNNN notation, i.e. 0x2 == 02h.
  
  For additional information on SCSI device codes refer to Understanding SCSI device/target NMP errors/conditions in ESX/ESXi 4.x and ESXi 5.0 (1030381)
  
  
  
• SCSI Sense Keys
  
  SCSI Sense Keys appear in the Sense Data available when a command returns with a CHECK CONDITION status. The sense key contains all the information necessary to understand why the command has failed.
  
  
  Code Name
  
  0h NO SENSE
  
  1h RECOVERED ERROR
  
  2h NOT READY
  
  3h MEDIUM ERROR
  
  4h HARDWARE ERROR
  
  5h ILLEGAL REQUEST
  
  6h UNIT ATTENTION
  
  7h DATA PROTECT
  
  8h BLANK CHECK
  
  9h VENDOR SPECIFIC
  
  Ah COPY ABORTED
  
  Bh ABORTED COMMAND
  
  Dh VOLUME OVERFLOW
  
  Eh MISCOMPARE
  
  
  For more information, see http://www.t10.org/lists/2sensekey.htm.
  
  Note: Hexadeximal numbers in the T10 documentation use the NNNh notation, whereas SCSI status codes logged to the ESX host use the equivalent 0xNNN notation, i.e. 0x2 == 02h
  
  
  
• SCSI Additional Sense Data
  
  SCSI Additional Sense Data takes the form of two value encoded bytes in the sense data, typically returned by the REQUEST SENSE command. The additional sense code (ASC) byte indicates information about the error exception reported in the sense key field. The additional sense code qualifier (ASCQ) indicates detailed information related to the additional sense code. See the clause describing the REQUEST SENSE command in the SCSI Primary Commands - 3 (SPC-3) draft standard for more information about sense data."
  
  |-> ASC value (in hexadecimal)
  
  ||
  
  || |-> ASCQ value (in hexadecimal)
  
  || ||
  
  || || |-> Codes identifying devices that may use the ASC/ASCQ pair
  
  || || |-> value. (See list of device code letters below.)
  
  || || |
  
  || || | | |-> Error or exception indicated by the
  
  || || | | |-> ASC/ASCQ pair value.
  
  || || |------------| |------------------------------------------|
  
  04/00 DTLPWROMAEBKVF LOGICAL UNIT NOT READY, CAUSE NOT REPORTABLE
  
  04/01 DTLPWROMAEBKVF LOGICAL UNIT IS IN PROCESS OF BECOMING READY
  
  04/02 DTLPWROMAEBKVF LOGICAL UNIT NOT READY, INITIALIZING COMMAND REQUIRED
  
  04/03 DTLPWROMAEBKVF LOGICAL UNIT NOT READY, MANUAL INTERVENTION REQUIRED
  
  
  For more information, see http://www.t10.org/lists/2asc.htm.
  
  
  Note: The above link was correct as of January 04, 2011. If you find a link is broken, provide feedback and a VMware employee will the link.
  
  

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