Product specifications

Infortrend
9-6
for disk drives. When S.M.A.R.T. is enabled, the drive monitors
predetermined disk drive attributes that are susceptible to
degradation over time.
If a failure is likely to occur, S.M.A.R.T. makes a status report
available so that the host can prompt the user to backup data from
the failing drive. However, not all failures can be predicted.
S.M.A.R.T. predictions are limited to the attributes the drive can
monitor which are selected by the device manufacturer based on the
attribute’s ability to contribute to predict degrading or fault
conditions.
Although attributes are drive specific, a variety of typical
characteristics can be identified:
• Head flying height
• Data throughput performance
• Spin-up time
• Re-allocated sector count
• Seek error rate
• Seek time performance
• Spin try recount
• Drive calibration retry count
Drives with reliability prediction capability only indicate whether
the drive is “good” or “failing.” In a SCSI environment, the failure
decision occurs on the disk drive and the host notifies the user for
action. The SCSI specification provides a sense bit to be flagged if
the disk drive determines that a reliability issue exists. The system
then alerts the user/system administrator.
B. Infortrend's Implementations with S.M.A.R.T.
Infortrend uses the ANSI-SCSI Informational Exception Control
(IEC) document X3T10/94-190 standard.
There are four selections related to the S.M.A.R.T. functions in
firmware:
Disabled
Disables S.M.A.R.T.-related functions
Detect Only:
When the S.M.A.R.T. function is enabled, the controller will send a
command to enable all drives' S.M.A.R.T. function, if a drive
predicts a problem, the controller will report the problem in an
event log.