Fujitsu MBA3073NC Computer Drive User Manual


 
2.1.5 Reliability
(1) Mean Time Between Failures (MTBF)
MTBF of the HDDs during its lifetime is 1,400,000 hours (operating: 24 hours/day, 7 days/week
average DE surface temperature: 50°C or less).
Continual or sustained operation at case DE surface temperature above 50°C may degrade product
reliability.
Note:
The MTBF is defined as:
Operating time (hours) at all field sites
MTBF=
The number of equipment failures from all field sites
Failure of the equipment means failure that requires repair, adjustments, or replacement.
Mishandling by the operator, failures due to bad environmental conditions, power trouble, host
system trouble, cable failures, or other failures not caused by the equipment are not considered.
(2) Mean Time to Repair (MTTR)
MTTR is the average time taken by a well-trained service mechanic to diagnose and repair an
HDD malfunction. The drive is designed for a MTTR of 30 minutes or less.
(3) Service life
The service life under suitable conditions and treatment is as follows.
The service life is depending on the environment temperature. Therefore, the user must design the
system cabinet so that the average DE surface temperature is as low as possible.
DE surface temperature: from 5°C to 40°C 5 years
DE surface temperature: from 41°C to 45°C 4.5 years
DE surface temperature: from 46°C to 50°C 4 years
DE surface temperature: from 51°C to 55°C 3.5 years
DE surface temperature: from 56°C to 60°C 3 years
DE surface temperature: more than 60°C, or less than 5°C No guarantee
(Keep the DE surface
temperature from 5°C to 60°C.)
Even if the HDD is used intermittently, the longest service life is 5 years.
The maximum storage period without turning the power on is six months.
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