Reliability; Reliability Specifications; Error Rates - Western Digital Re EX800M Technical Reference Manual

EX800M
4.0 R
ELIABILITY
4.1

Reliability Specifications

The following reliability specifications assume correct host/drive operational interface, including all
interface timings, power supply voltages, environmental requirements and drive mounting constraints.
You can enhance the reliability of the WD hard drive by ensuring that the drive receives adequate
cooling. Section 2.5.3 Temperature Measurement on page 14 provides temperature measurements and
other information that may be used to enhance the service life of the drive. Recommended airflow
information is provided in Section 2.5.4 Cooling on page 15. The drive shall achieve the MTBF as
specified below when operated in an environment that ensures the HDAs base temperatures specified
in Section 2.5.3 Temperature Measurement on page 14 are not exceeded. Continual or sustained
operation at base temperatures above the values shown in Section 2.5.3 Temperature Measurement on
page 14 may degrade product reliability. The drive incorporates industry standard Self Monitoring,
Analysis and Reporting Technology (SMART).
MTBF is based on the following assumptions:
Average POH
Average Power-on
Cycles
Temperature
Power Voltages
Cooling
Workload
Drive Warranty
Serviceable Life
Demonstrated MTBF
Predicted AFR
Preventive
Maintenance
4.2

Error Rates

The error rates stated in this specification assume the following:
The drive is operated per the DC power specified.
The drive has been formatted with the FORMAT UNIT command.
Errors previously detected as caused by media defects are excluded from further error rate
computations.
Random error distribution
2679-771339-A05
8760 Hours/Year (Power on Hours)
Up to 5,000 cycles/year (10,000 cycles/year when the hard drive spindle is stopped
prior to power removal)
The allowable continuous or sustained HDA base temperature for the rated MTBF is
40°C. The maximum allowable HDA base temperature is 60°C (140°F). Operation of
the drive at the maximum base temperature is intended for short time periods only.
Continuous operation at the elevated temperatures will reduce product reliability and
void product warranty.
As defined in Section 2.4.4 Input Voltage Requirements on page 10.
Systems will provide adequate cooling to ensure the base temperatures are not
exceeded
Seen by the system as the total amount of data read from or written to the drive;
workload should not exceed an annualized total of 550 TB/year. System data
transferred in excess of this workload can lead to accelerated failure rates and impact
product reliability.
5 years
5 years minimum, assuming 8760 hours/year or less
1,200,000 hours. MTBF data is demonstrated using actual drives populated into the
RDT chambers for specified period.
0.73% AFR (target)
None Required
RELEASED 8/13/13

Reliability

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