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How Power Failures Corrupt Flash SSD Data

Posted by Soulskill on from the not-so-solid-state dept.

An anonymous reader writes "Flash SSDs are non-volatile, right? So how could power failures screw with your data? Several ways, according to a ZDNet post that summarizes a paper (PDF) presented at last month's FAST 13 conference. Researchers from Ohio State and HP Labs researchers tested 15 SSDs using an automated power fault injection testbed and found that 13 lost data. 'Bit corruption hit 3 devices; 3 had shorn writes; 8 had serializability errors; one device lost 1/3 of its data; and 1 SSD bricked. The low-end hard drive had some unserializable writes, while the high-end drive had no power fault failures. The 2 SSDs that had no failures? Both were MLC 2012 model years with a mid-range ($1.17/GB) price.'"

3 of 204 comments (clear)

  1. build in some power storage by X0563511 · · Score: 5, Insightful

    Seriously... slap in some basic power circuitry and some caps - enough that the drive can finish the cycle it is on and do whatever it needs to do to power off safely.

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    For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
    1. Re:build in some power storage by v1 · · Score: 5, Insightful

      space is at an extreme premium in those drives. There's a reason they feel so heavy/dense. Given the quilting layout of the chips, adding a single cap would prevent several memory chips from fitting. So you may as well then fill that remaining space with more caps. But you will reduce capacity, and that's what sells SSDs.

      There's already a substantial amount of circuitry in them, far from "basic". It's essentially a CPU. I'd be interested to see some numbers as to average power drain during idle, read, and write.

      The ones that did the best during the power blips probably did have caps and a bit more in their power system to handle it though. It certainly does surprise me that the mid-range, not the high-end, were the best performers in this test.

      --
      I work for the Department of Redundancy Department.
  2. Re:We encountered something like this by yurtinus · · Score: 5, Insightful

    Likely as part of an embedded system - monitoring or control software. Systems where you just flip the power switch on when you need them and off when you're done, so an UPS wouldn't apply.

    I'm not saying their implementation was right, just saying that you can't imply from his post that it was wrong :P

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    +1 Disagree