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5.2.1
Annualized Failure Rate (AFR) and Mean Time Between Failure (MTBF)
The production disk drive shall achieve an annualized failure-rate of 0.44% (MTBF of 2,000,000 hours) over a 5 year service life when
used in Enterprise Storage field conditions as limited by the following:
• 8760 power-on hours per year.
• HDA temperature as reported by the drive <= 50C
• Ambient wet bulb temp <= 26°C
• The AFR (MTBF) is a population statistic not relevant to individual units.
• ANSI/ISA S71.04-2013 G2 classification levels and dust contamination to ISO 14644-1 Class 8 standards (as measured at the device)
The MTBF specification for the drive assumes the operating environment is designed to maintain nominal drive temperature and humidity.
The rated MTBF is based upon a sustained drive temperature of up to 122°F (50°C) and wet bulb temperature up to 78.8°F (26°C).
Occasional excursions in operating conditions between the rated MTBF conditions and the maximum drive operating conditions may occur
without significant impact to the rated MTBF. However continual or sustained operation beyond the rated MTBF conditions will degrade the
drive MTBF and reduce product reliability.
5.2.2
Preventive maintenance
No routine scheduled preventive maintenance is required.
5.2.3
Hot plugging the drive
When a disk is powered on by switching the power or hot plugged, the drive runs a self test before attempting to communicate on its'
interfaces. When the self test completes successfully, the drive initiates a Link Reset starting with OOB. An attached device should
respond to the link reset. If the link reset attempt fails, or any time the drive looses sync, the drive initiated link reset. The drive will initiate
link reset once per second but alternates between port A and B. Therefore each port will attempt a link reset once per 2 seconds assuming
both ports are out of sync.
If the self-test fails, the drive does not respond to link reset on the failing port.
Note.
It is the responsibility of the systems integrator to assure that no temperature, energy, voltage hazard, shorting of PCBA to
ground, or ESD potential hazard is presented during the hot connect/disconnect operation. Discharge the static electricity
from the drive carrier prior to inserting it into the system.
Caution.
The drive motor must come to a complete stop prior to changing the plane of operation. This time is required to insure data
integrity.
5.2.4
S.M.A.R.T.
S.M.A.R.T. is an acronym for Self-Monitoring Analysis and Reporting Technology. This technology is intended to recognize conditions that
indicate imminent drive failure and is designed to provide sufficient warning of a failure to allow an application to back up the data before an
actual failure occurs.
Note.
The drive's firmware monitors specific attributes for degradation over time but can't predict instantaneous drive failures.
Each monitored attribute has been selected to monitor a specific set of failure conditions in the operating performance of the drive and the
thresholds are optimized to minimize "false" and "failed" predictions.
Controlling S.M.A.R.T.
The operating mode of S.M.A.R.T. is controlled by the DEXCPT and PERF bits on the Informational Exceptions Control mode page (1Ch).
Use the DEXCPT bit to enable or disable the S.M.A.R.T. feature. Setting the DEXCPT bit disables all S.M.A.R.T. functions. When enabled,
S.M.A.R.T. collects on-line data as the drive performs normal read and write operations. When the PERF bit is set, the drive is considered
to be in "On-line Mode Only" and will not perform off-line functions.
Applications can measure off-line attributes and force the drive to save the data by using the Rezero Unit command. Forcing S.M.A.R.T.
resets the timer so that the next scheduled interrupt is in one hour.
Applications can interrogate the drive through the host to determine the time remaining before the next scheduled measurement and data
logging process occurs. To accomplish this, issue a Log Sense command to log page 0x3E. This allows applications to control when
S.M.A.R.T. interruptions occur. Forcing S.M.A.R.T. with the RTZ command resets the timer.
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