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For someone who seeks an external hard drive as reliable as possible, where size is not an issue and cloud backup is not an option: would a desktop external hard drive be less fallible than a portable external hard drive?
There must some drastic hardware or setup differences, because they vary so much. For example, a 2TB desktop external hard drive, usually a 3.5-inch, is over 2 pounds, yet its portable counterpart, usually a 2.5-inch, is merely half a pound! ?If the storage pieces are exactly the same size and weight (they might not even be), then the spacing of parts must be different. In that case, wouldn’t the smaller hard drives be more prone to overheat? There must be other issues too.
So I would like to know how they are built, how they are different, and in turn, which one has a lower chance of failure.
edit: Please share your knowledge and thoughts, as there is no consensus yet. edit#2: Solid state drives right now are too expensive for me.
Answer: A low quality consumer grade 2.5″ drive will be less reliable than an enterprise 3.5″ drive, but if we assume all else equal, is there a reliability advantage in a particular form factor?
In Next Generation Mobile Hard Disk Drives (2006, Fujitsu), Fujitsu says this:
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2.5 HDDs have lower power and offer improved MTBF and life.
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All hard disk drives are susceptible to damage by excessive heat. Mobile hard disk ?drives tend to be operated in a high temperature, low airflow environment and are ?therefore perceived to have lower reliability. If mobile hard disk drives were operated in ?an enterprise environment with constant temperature, then the demonstrated MTBF ?would prove to be an improvement over the mobile specification.
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Testing has shown the largest contributor to the life of a hard disk drive is the operating ?temperature. Heat from the application environment and sense current exacerbates ?electron migration in small semiconductors. ?… ?Through a few important design changes, hard disk drive suppliers have created 2.5 ?hard disk drives that operate 24×7 at a DE surface temperature of 55 C.
In the end, Fujitsu claims that the 2.5″ form factor is objectively more reliable, all else being equal. Principal contributors to the claims are the lesser mass and the extra engineering that goes into making 2.5″ drives survive the more harsh conditions of mobile use (specifically, temperature and shock/vibration).
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Summary ?Small form factor hard disk drives offer the advantage of lower power, higher capacity ?and higher performance per cubic volume when compared to 3.5 hard disk drives as ?well as more than adequate reliability and life when operated in a controlled environment ?with temperatures below 55 C.
Since all else rarely is equal, looking at MTBF and duty cycle ratings will give you a stronger impression of a given drive’s relative reliability against another. For example, looking across the 2.5 and 3.5 enterprise (24×7) drives at HGST, we see that many of the 2.5″ models have an MTBF of 2M hours, while the 3.5″ drives come in at 1.4 to 1.6M.
This question is possibly identical to the ServerFault question Is there a reliability difference between 2.5 and 3.5 HDDs?