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The mysteriously disappearing drive: Are power outages killing your SSDs?


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The mysteriously disappearing drive: Are power outages killing your SSDs?




SSDs offer enormous benefits over traditional spinning discs. They’re up to an order of magnitude faster in certain operations, weigh less, and consume less power under load. They’ve become increasingly popular with enthusiasts and mainstream customers alike — but a report from the 11th Usenix Conference on File and Storage Technologies (FAST 13), given early this year, suggests most models have a fundamental problem with sudden power loss. While the paper came out in mid-February, I only recently came across it, after a reader asked if I’d look into a rather puzzling recovery program recommended by Crucial for its M4 SSD line.
Crucial recommends that M4 owners whose drives suddenly vanish simply let the drive sit for some 40-60 minutes with the SATA connector disconnected, but the power cable still connected. The company recommends that laptop owners let their systems sit in the BIOS screen, and there’s no word if this is also better for the desktop drives as well. USB 3.0 enclosures are considered sub-optimal. Baffled, I began to poke at this further, then stumbled across the aforementioned report from early this year.



 Researchers working with the University of Ohio rounded up 15 different SSDs from five different vendors, as well as a brace of HDDs, and put them through a series of tests designed to measure how they responded to sudden power failures. No vendors are identified, but the drives in question incorporate both MLC and SLC. Some (the SLC versions) are explicitly enterprise drives. Some include supercapacitors, which are designed to mitigate catastrophic power failure.

The results were not encouraging. (More...)


Read the complete story at: http://www.extremetech.com/computing/169124-the-mysteriously-disappearing-drive-are-power-outages-killing-your-ssds



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Based upon that article, a large electrolytic capacitor can solve that problem.  Since the SSD draws little power, the capacitor's charge will sustain the power during the last critical internal functions after a loss of power.  The question would be how long is that time period and what capacity in Farads would be needed to sustain the activity during that time frame.  Sure a UPS would mitigate that but that's true for the entire system and not just because one has a SSD.

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Having a UPS would be handy, only if the user checks the UPS from time to time, I have seen folks that have had them for 10 years and never replaced the batteries, so when the power went, the UPS did not leave the computer on, basically it was just a power strip then....

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UPS have AGM type batteries in them, which are very good and last roughly 5 years. One needs to have a maintenance plan for those, just like the ones in alarm systems and smoke detectors. Just so we don't forget. As far as a UPS goes, it's pretty easy to tell when the battery is fried because your computer will have shut down after a short electrical event (it should remain On). I guess many will overlook that though. I would think that even a dead battery would *filter* voltage spikes.

I have a Crucial M4 and a UPS, so I feel a little better now..

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hmmm ...

a small "sub supply" (provided by a lithium primary or rechargeable battery) that is used to "back up" just the SSDs .

think battery , diode steering and isolation unit that plugs in series between the sata power connector and the ssd or an "adapter" type that transitions between the old style molex connector and converts to sata .

lessee here ... two lithium cells in series is 6 volts ... with a .7 volt drop across the isolation diode it would leave 5.3 volts ... right in the ballpark for 5 volt tolerance .

the charging circuit for rechargeable lithium or NiCd cells would be more complicated but could run of of the 12 volt buss .

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