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Flash Destroyer Tests Limit of Solid State Storage 229

An anonymous reader writes "We all know that flash and other types of solid state storage can only endure a limited number of write cycles. The open source Flash Destroyer prototype explores that limit by writing and verifying a solid state storage chip until it dies. The total write-verify cycle count is shown on a display — watch a live video feed and guess when the first chip will die. This project was inspired by the inevitable comments about flash longevity on every Slashdot SSD story. Design files and source are available at Google Code."
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Flash Destroyer Tests Limit of Solid State Storage

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  • for the guy (Score:3, Insightful)

    by phantomfive ( 622387 ) on Thursday May 27, 2010 @03:10PM (#32367452) Journal
    For the guy a couple days back who asked what kind of project can he do that would be useful to the world, here is a great example. Try something like this.
  • Re:live stream (Score:3, Insightful)

    by biryokumaru ( 822262 ) <> on Thursday May 27, 2010 @03:19PM (#32367600)

    They should have a bit torrent-like system for streams. Like, you just connect to the swarm and request a fairly recent image. Everyone keeps the past minute or so cached to send to new people in the swarm. Maybe a tiered system so that the people who have been connected longest are closest to the original stream.

    Let's say I connect to Joe and Mary, who're connected to the original server. They send me frames two or three frames behind the server. Jack connects, and he's getting a bit lagged images too, right with me. Now Sally connects and she's behind me and Jack, so Me, Jack, Joe and Mary all send her images. It's like a pyramid scheme for streaming video.

    Now Joe leaves. I've been around longer than Jack, so I move up in the tiers. I see a single frameskip, but now I'm connected directly to the source stream.

    The real purpose here is to relieve some of the pressure from the initial server. Maybe they've got 100/100, and I connect with my 20/5. Well, 5 isn't much compared to 100, but I'm pulling less than 1. Let's call it 1. Now the available bandwidth for streaming is 105 and I'm only using 1. With all them other folks connected up, the server might be only holding half the load. And higher bandwidths could get tiering priority, like, if I have 100/100, well, I get directly connected to the server pretty quick so I can redistribute the stream faster.

    Oh, that's right, video comes in streams, not images... well, okay, it's got some problems. But it seems like a good solution to a very, very common problem. Make things easier on Hulu and Youtube (cause we all know they need the help, right?) and such too. Maybe drastically reduce the barrier for entry into that field, at least.

    Just a thought.

  • by Rick Richardson ( 87058 ) on Thursday May 27, 2010 @03:21PM (#32367636) Homepage

    The display only goes to 9,999,999! I think that won't be enuf... should be 100M or 1G.

  • Re:Interesting! (Score:5, Insightful)

    by Smallpond ( 221300 ) on Thursday May 27, 2010 @03:30PM (#32367788) Homepage Journal

    Mechanical disks have lots of great failure modes. You can do seek tests until the arm breaks or voice coil fails, you can do write/read tests until you get enough bad sectors that they can't recover the data any more, or you can do start-stop of the drive motor until it dies. Another good one is to stop the motor for a while, then see if it starts up or has stiction (sic), but that test takes a long time. If the drive is not held rigidly enough, vibration will kill it, and it it isn't cooled properly, heat will kill it. Did I miss any?

  • by Edmund Blackadder ( 559735 ) on Thursday May 27, 2010 @03:32PM (#32367828)

    Most modern flash memories have their controllers check which blocks are dying or dead and re-route write and read requests to good blocks. So while your flash may seem to be working perfectly well, various blocks inside it may be dying and its storage size may be progressively decreasing.

    So I hope they are rewriting the entire flash in their test. Otherwise it is not representative.

  • Re:Interesting! (Score:4, Insightful)

    by msauve ( 701917 ) on Thursday May 27, 2010 @03:38PM (#32367918)

    since this test isn't on an actual, shipping solid state drive (SSD) product, the results will be discounted by a lot of critics.

    Assuming that the flash is of equivalent technology (e.g. SLC NAND, cell size, etc) to that used for SSD, then this would present a best case test, since it is exercising all cells equally.

    An SSD tries to do wear leveling (distribute writes evenly), but that can't done perfectly, as is done in this test.

  • Re:Interesting! (Score:5, Insightful)

    by Dancindan84 ( 1056246 ) on Thursday May 27, 2010 @03:40PM (#32367954)
    And honestly it's a pretty valid argument. This is definitely going to be informative, but I'm just as interested in how a particular SSD handles the flash blocks failing as when they fail. A SSD with flash that averages 1,000,000 writes before blocks start to fail but does it gracefully with little/no data loss could be better than one that averages 2,000,000 but goes out in a blaze of glory as soon as the first block fails.
  • Re:Interesting! (Score:5, Insightful)

    by Pharmboy ( 216950 ) on Thursday May 27, 2010 @03:46PM (#32368030) Journal

    Or connect the drive inside any computer running a Prescott P4 with 100% CPU utilization.

  • by fnj ( 64210 ) on Thursday May 27, 2010 @03:48PM (#32368066)

    Nonsense, it's completely representative of normal use. That's exactly the point. Until data loss occurs, or there are no more free blocks to use, the flash memory is objectively perfectly good.

  • Re:Die? (Score:3, Insightful)

    by fbjon ( 692006 ) on Thursday May 27, 2010 @03:54PM (#32368150) Homepage Journal
    It may be that the controller on the device just doesn't know what to do when something goes pear-shaped. To be sure, you should be accessing the raw NAND chip itself.
  • Re:Huh? (Score:5, Insightful)

    by Denis Lemire ( 27713 ) on Thursday May 27, 2010 @04:17PM (#32368480) Homepage

    Graceful as in data not related to your recent failed writes are still readable so they can be backed up and migrated to a new drive. Not sure why that concept is so difficult. I consider something dead as "completely unreadable, ALL your data has been destroyed - have a nice day."

    No longer reliable but still semi recoverable isn't quite "dead."

    Maybe I'm just using a stricter interpretation of the word dead than you are?

    Let's use a marker on a white board analogy. If I was storing all my data on a suitably large white board using a marker and I completely exhausted my marker's supply of ink, I'd be pissed if this resulted in a blank whiteboard, wouldn't you? On that same note, if I wiped a small section of my whiteboard with the intent of writing something new in that area and only then realized that my marker was no longer suitably supplied with ink and my write failed, I would find the blank void in that section alone acceptable.

    Does that clarify things?

  • Re:Interesting! (Score:4, Insightful)

    by BikeHelmet ( 1437881 ) on Thursday May 27, 2010 @04:58PM (#32369028) Journal

    I just hang around on the NCIX forums, and every day or two there's a person complaining about having to RMA their SSD because programs started crashing, and then finally they couldn't even boot it.

    I saw lots of people replying in threads, saying theirs were still working fine. I started asking everyone how long they had owned theirs. Most with working SSDs were in the 8-15 months range, and most with serious problems were in the 12-24 months range.

    I've noticed that SSD warranties from a lot of manufacturers have dropped from the original 5 years down to ~2. That's quite a drop. There must be a reason.

    I suspect a heavy disk user like myself would burn through one well before the warranty is up.

    Note: My sample is pretty small compared to the amount sold, but I do wonder how many die without the owners being vocal about it.

    I'm wondering if close to two years ago manufacturers flipped to cheaper NAND to get the prices down? Now prices are going back up, so maybe manufacturers realized their mistake? Even since January, SSD prices have gone up 20-30% on average. $89.99 SSDs are now $120+ []

  • by tepples ( 727027 ) <tepples AT gmail DOT com> on Thursday May 27, 2010 @06:06PM (#32369768) Homepage Journal

    The AC actually posited a worse case scenario, in that the whole disk was filled, and only one "spot" was repeatedly changed.

    There are two ways to handle this:

    • Reserve 5% to 7% of sectors to replace worn-out sectors. This conveniently happens to match the difference between 64 GB and 64 GiB. Some newer SSDs have "250 GB", which leaves over 9% of a 256 GiB module free for the controller to spread writes.
    • Move this unchanging data from less worn sectors to more worn sectors to free up the less worn sectors for more rapidly changing data.
  • Re:Interesting! (Score:2, Insightful)

    by mysidia ( 191772 ) on Thursday May 27, 2010 @06:24PM (#32369950)

    He said an oven not a nuclear fusion core.

    The response was a Prescott P4 at 100% CPU, not an SCC / 48-CORE Intel Many-Cores(TM) chip with all cores at continuous 100% utilization

Mausoleum: The final and funniest folly of the rich. -- Ambrose Bierce