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Never Underestimate the Bandwidth of a Suburban Filled With MicroSD Cards

Posted by timothy on from the eggs-in-one-basket dept.

toygeek writes "If you've been in IT long enough, you're bound to have heard the phrase 'Never underestimate the bandwidth of a station wagon filled with backup tapes.' These days moving data has become so much easier; We've surpassed baud rates and are into Gbps fiber on the backbones, and even in some homes. So, what's the modern equivalent to this, and what does it take to make the OC fiber connections cringe? Follow along as we theoretically stuff MicroSD cards into a Chevy Suburban and see what happens, and take sneakernet to a whole new level."

13 of 208 comments (clear)

  1. This is pointless by Anonymous Coward · · Score: 5, Informative

    The original saying was coined in a time where reading from a tape *was considerably faster* than reading over a network. Hence, transferring data via sneakernet was quicker, inclusive of the read-write times.

    Now, with multi-gigabit pipes making up the networks, data can be written, pushed, and read again, all at much higher bitrates than reading any storage medium. It's the read-write to physical medium that are the bottleneck with the sneakernet now.

    1. Re:This is pointless by mooingyak · · Score: 4, Informative

      Now, with multi-gigabit pipes making up the networks, data can be written, pushed, and read again, all at much higher bitrates than reading any storage medium. It's the read-write to physical medium that are the bottleneck with the sneakernet now.

      TFA says that they have 19 million SD cards. If each one is a mid-range 6 megabyte per second speed and we access them all in parallel, that gives 912 terabit per second potential max bandwidth, which almost certainly exceeds any network you're thinking about.

      19M card readers (or slots or whatever) probably isn't even necessary.. I'm sure working in rotation you'd have a steady stream of cards whose data was fully read before other cards are even unpacked. I believe the optimal number of card readers would be (time to read) / (time to unpack).

      --
      William of Ockham had no beard. The most likely explanation is that it was chewed off by squirrels every morning.
    2. Re:This is pointless by Zero__Kelvin · · Score: 2, Informative

      "That would take far more time than the actual trip itself, but we're not counting it because the original saying "Never Underestimate the Bandwidth of a Station Wagon Filled with Backup Tapes" didn't count it either."

      The AC actually had something to say. That is rare and should be encouraged, not discouraged. He specifically pointed out why it wasn't considered ("The original saying was coined in a time where reading from a tape *was considerably faster* than reading over a network. Hence, transferring data via sneakernet was quicker, inclusive of the read-write times.", assuming it wasn't considered, which is a poor assumption backed by zero evidence, clearly made to try to lend credibility to a worthless idea and point.

      --
      Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
    3. Re:This is pointless by icebike · · Score: 5, Informative

      Well, actually not a poor assumption, considering that TFA also indicates that much data is 398,772 3TB hard drives and, moving that much data onto or off of that many drives isn't something that even Google can do in the time period measured. They discounted read-and write times on both media types.

      (Although they make no allowance for handling). Its a fun mind game, but as usual a pointless exercise.
      The Microsd cards will cost you $855 million dollars, and probably consume the entire production of 64gb cards for a year.

      --
      Sig Battery depleted. Reverting to safe mode.
    4. Re:This is pointless by bored · · Score: 4, Informative

      That is true for something like SD, but modern tape drives can do well over 500MB/sec in compressed streaming mode, and have native uncompressed capacities of 8.5TB.

      That means that even with a midrange tape library with 56 drives, your talking a read/write bandwidth of 27GB/sec (aka 1/3 Tbit/sec). Tape bandwidth scales linearly with the number of drives in the library, and things like the the SL8500 from STK can support up to 640 drives.

      It still faster if you have a PB of data you need shipped from NY to LA to write it to tape, put it on a plane and read it back in LA. Plus, it all fits nicely into a big suitcase. Furthermore, even for smaller amounts of data (say 10-20TB a day) the cost of a tape drive and an next day delivery is going to be significantly less than the Gbit/sec or so of bandwidth required to ship a similar amount of data in most places in the US.

    5. Re:This is pointless by blackraven14250 · · Score: 1, Informative

      It was probably chosen for data density per volume.

  2. Common sense almost prevails by jlf278 · · Score: 5, Informative

    From the article: "A MicroSD card is only .1 cubic inches, so if all things were equal you could stuff 100 64gb cards into a cubic inch of space! But, that does not seem realistic. In fact it doesn't even seem remotely possible." Perhaps that's because 1 cubic inch = 10 * 0.1 cubic inches and not 100 * 0.1 cubic inches.

    1. Re:Common sense almost prevails by jlf278 · · Score: 3, Informative

      ah, their mistake was the MicroSD card is only 0.01 cubic inches.

  3. XKCD by Anonymous Coward · · Score: 5, Informative

    http://what-if.xkcd.com/31/
    That is all

  4. This old chest nut again by kannibal_klown · · Score: 4, Informative

    Great, you've managed to transfer X terrabytes of data across state lines. I salute you.

    Now... go find this list of files that I need. Also that collection of data that our servers need to process. What, that's going to take you HOW long?

    Yes might be quicker to send the data from point A to point B by just shipping disks... but only for archiving purposes. If you actually need to access the data, then you still have that last mile (or 10') of having to load that data into a system or network.

    Now, if you were shipping a truck load of servers, or maybe a car full of NAS devices that you could just plug into a network and be done with it... then it's not too bad. Then you can start electronically searching the data within minutes, index it, use it for your data-store, whatever.

    But just a car load of disks for non-archival purposes... you're asking for a headache.

  5. They forgot something by davydagger · · Score: 1, Informative

    they forgot the time it takes to transfer data onto the SD cards, remove them, and fill the truck. add another 24 hours

  6. Petabyte tablet by Ken_g6 · · Score: 3, Informative

    In 3001: The Final Odyssey, Arthur C. Clarke wrote about a petabyte tablet as though it were the ultimate storage medium, something humanity finally arrived at after a millennium. In the book it was enough to store the contents of a human brain!

    16,000 or so microSD cards could store a petabyte in roughly a 1-foot by 1-foot by 2-inch space, probably leaving enough room to wire them up as well. Of course, it would cost nearly a million bucks, not counting the hardware necessary to wire it up to be accessed. But, still, I find that very impressive.

    --
    (T>t && O(n)--) == sqrt(666)
  7. Re:Jet full of CDs by F34nor · · Score: 1, Informative

    The real fucking quote is...

    Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway. —Tanenbaum, Andrew S. (1989)