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posted by martyb on Sunday May 10 2015, @10:37PM   Printer-friendly
from the powerlessness dept.

An SSD stored without power can start to lose data in as little as a single week on the shelf, depending on several factors. When most drives storage were mechanical, there was little chance of data loss or corruption so quickly as long as the environment in the storage enclosure maintained reasonable thresholds. The same is not true for SSDs and the Joint Electron Device Engineering Council (JEDEC), which defines standards for the microelectronics industry including standards for SSDs, shows in a presentation that for every 5 degrees C (9 degrees F) rise in temperature beyond the optimal where the SSD is stored the data retention period is approximately halved.

In a presentation by Alvin Cox on JEDEC's website titled "JEDEC SSD Specifications Explained" [PDF warning], graphs on slide 27 show that for every 5 degrees C (9 degrees F) rise in temperature where the SSD is stored, the retention period is approximately halved. For example, if a client application SSD is stored at 25 degrees C (77 degrees F) it should last about 2 years on the shelf under optimal conditions. If that temperature goes up 5 degrees C, the storage standard drops to 1 year.

[...] When you receive a computer system for storage in legal hold, drive operating and ambient storage temperature are probably not the first things on tap to consider. You cannot control the materials that comprise the drive and the prior use of the drive. You can control the ambient temperature of the storage which will potentially aid in data retention. You can also ensure that power is supplied to the drives while in storage. More importantly, you can control how the actual data is retained.

[...] What started this look into SSDs? An imaging job of a laptop SSD left in storage for well over the 3-month minimum retention period quoted by the manufacturer of the drive before it was turned over to us. This drive had a large number of bad sectors identified during the imaging period. Not knowing the history, I did not consider the possibility of data loss due to the drive being in storage. Later, I learned that the drive was functioning well when it had been placed into storage. When returned to its owner a couple of months after the imaging, the system would not even recognize the drive as a valid boot device. Fortunately, the user data and files were preserved in the drive image that had been taken, thus there was no net loss.

Now imagine a situation in which an SSD was stored in legal hold where the data was no longer available for imaging, much less use in court. Ignorance of the technology is no excuse, and I am sure the opposing counsel would enjoy the opportunity to let the court know of the "negligent" evidence handling in the matter.

 
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  • (Score: 3, Informative) by Subsentient on Monday May 11 2015, @12:31AM

    by Subsentient (1111) Subscriber Badge on Monday May 11 2015, @12:31AM (#181267) Homepage Journal

    I was hesitant on SSDs for a number of reasons, including trouble with swap space, bad write speeds, and data retention. Looks like I was right.

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  • (Score: 2) by Grishnakh on Monday May 11 2015, @03:04AM

    by Grishnakh (2831) on Monday May 11 2015, @03:04AM (#181322)

    Yep, me too, for most of the same reasons, and also capacity (I like being able to store a bunch of movies and music on my laptop without spending an arm and a leg). I guess I'll stick with my spinning platters for now.

  • (Score: 1) by Bogsnoticus on Monday May 11 2015, @04:13AM

    by Bogsnoticus (3982) on Monday May 11 2015, @04:13AM (#181347)

    Given that SSD's have a limited write/read cycle on them, I go along and actively disable swap spaces, and have yet to see a perform decrease from it.

    Lifehacker has a handy guide to maximising your SSD lifespan here. [lifehacker.com]

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  • (Score: 2) by TheRaven on Monday May 11 2015, @08:04AM

    by TheRaven (270) on Monday May 11 2015, @08:04AM (#181396) Journal
    Bad write speeds? The SSD in my laptop can happily handle 300MB/s of sequential writes and 30-100MB/s of random writes. The one in the laptop it replaced was only slightly slower. Some of the newer ones are noticeably faster.
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    • (Score: 2) by tempest on Monday May 11 2015, @03:17PM

      by tempest (3050) on Monday May 11 2015, @03:17PM (#181492)

      I had a similar experience with an Intel (forgot the model) SSD. For intense heavy continuous writes it had about 1/3 less throughput than a WD Raptor. It's a special use case I happen to have, so I wouldn't dissuade a normal user from getting an SSD for that reason alone.

  • (Score: 2) by mtrycz on Monday May 11 2015, @08:12AM

    by mtrycz (60) on Monday May 11 2015, @08:12AM (#181399)

    I placed a modern SSD in my laptop, and switched the DVD-reader for an HHD caddy. I would use the DVD reader like once a year, probably.

    I expect my (modern) SSD to last some 10 years, before I switch it, according to my manufacturer. The problem is that there are actually no test cases for a 10y lifespan, (because the technology exists for less than that), but lab tests executing as much writes as "normal" use over 10years said it would last. Could be marketing of course.

    One problem with SSDs is taht, unlike HDDs, failure is binary and sudden. An HHD will give you signs of dieing with weeks of problems and degraded performance. An SSD is likely to ust fail. A weekly backup should do tho (if you store your data on the secondary HDD).

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    • (Score: 2) by TheRaven on Monday May 11 2015, @04:13PM

      by TheRaven (270) on Monday May 11 2015, @04:13PM (#181517) Journal

      An HHD will give you signs of dieing with weeks of problems and degraded performance

      If you're lucky. In my experience, that happens about half the time, the other half they just spontaneously fail. Google's numbers show that SMART errors indicate that a drive is about to fail, but lack of SMART errors don't indicate that it isn't.

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  • (Score: 2) by wantkitteh on Monday May 11 2015, @08:19AM

    by wantkitteh (3362) on Monday May 11 2015, @08:19AM (#181400) Homepage Journal

    Perhaps for your particular usage case - if you're compiling the Linux kernel on a low memory system stored in a non-air conditioned shipping container on the surface of a hot desert for six months, maybe you have a point. ;)