back to article Software defined? No no no, it's poorly defined storage (and why Primary Data is different)

"Software-defined storage" is something end users love, and the industry is going precisely in that direction. The only problem I have with it is that, as happens with other buzzwords, the term is being over-abused, and generalization leads to confusion. I know that I'm not the first to raise this problem, but now that real …

  1. Mr.Nobody

    Good luck with getting people to refer to something with words that actually describe it

    I have been ranting about the misuse of the acronym SAN to anyone who would listen, and obviously that went nowhere.

    Storage Area Network - if everyone started referring to Fiber/iscsi Switches as the SAN I probably wouldn't have blinked, but it just took a bunch of marketing morons somewhere to think Storage Array = SAN and that was that. Now its fing using everywhere - SAN SAN SAN SAN. Makes me want to start fires....

    1. Anonymous Coward
      Anonymous Coward

      Re: Good luck with getting people to refer to something with words that actually describe it

      Glad I'm not the only one who thinks this. The quick and easy way to discredit yourself as someone who has any knowledge of storage is to refer to a storage system as a Storage Area Network. The network's the bit you use to string it all together you moron. Ditto "arrays". Made sense when your system consisted of a single array but when it has many, or none at all, then you're not making much sense. That one's maybe excusable for the oldies who are stuck in their ways though.

      As for "software-defined", yes it's meaningless marketing bullshit, a bandwagon on which most of the big vendors have wasted a lot of money by applying their term to everything they produce which runs software (i.e. all of it). Storage systems have used standard Intel CPUs for years, as they're more than capable, with a standard Linux or BSD kernel, of running the number-crunching functions that could at one time only be achieved using ASICs, firmware and low-level assembler routines.

      What the "software-defined" morons are getting at is the ability to use off-the-shelf hardware. But then again, most vendors are already doing that, even if it's servers that they produce themselves. Why do they do this? Because they have access to the development teams who produce those servers and can iron out bugs so that the end user doesn't have to. If you buy a piece of storage software and choose any old kit, you're doing the testing and qualification yourself. Nothing wrong with that, as long as you take it into account, and architect your entire solution to expect the worst to happen. And you make sure you have a skilled in-house team who will be available in the middle of the night / their birthday / Christmas day to fix it, and have the ability to do so. Oh, and you can hang on to them if they decide they want to be paid more.

      Of course, a cloud computing provider, for example, will probably have such skills in-house and storage software is probably worth considering. Someone running, say, a large retailer, a council, or a financial institution is more likely to want to spend some cash getting a vendor in who will provide them 365 day 24 hour support so that their organisation doesn't go tits up in the event of an obscure bug rearing its ugly head.

      Then you need to consider, once you have this all set up, how are you going to scale this out and up in future. Because you're going to be doing it yourself or you're going to be forking out for someone else to do it. And they're going to want to be paid.

  2. JeffyPoooh


    Even little USB sticks have migrated from ASIC based controllers to ARM processor based controllers. The IC (or embedded) between the Flash Memory and the USB pins. This is related to the news about the malware hidden in the controller, not in the flash and thus invisible.

    So yeah, software is everywhere.

  3. Terry Cloth
    Thumb Up

    Thanks for the clarification

    As someone whose main interest in ``software-defined'' is radio (and whose network comprises two or three computers and an ADSL modem), I've always been fuzzy on SDN, and now SDS. Your explanation shows that it's just another layer of indirection. Thanks for making it as clear as I need it to get on with my life.

    1. Anonymous Coward
      Anonymous Coward

      Re: Thanks for the clarification

      The lowest level piece of storage that anyone accesses, including the vendors, is the disk drive. In its basic form you give the disk drive an address and the amount of data you want to read or write. The disk drive itself decides which platter/head etc. to use.

      Anything on top of that is a layer of abstraction, or virtualisation if you prefer, whether you're combining multiple devices into a single addressable space (block virtualisation), or creating an object-addressable layer, or file system (files are just objects, with specific metadata such as inodes or file names).

      This abstraction is performed using a combination of hardware and software and always will.

      Software-defined doesn't mean that everything is just done in the software, as its crappy name implies. It just means that that's the bit you're buying from the storage vendor. You buy the hardware elsewhere, but you still have to buy it You can buy a copy of Windows but you still need to get a computer to run it on.

      As for the author's claim that software-defined separates the data from the code which decides where it's going, I don't buy it. Storage systems all separate data from the logic that controls it. If they didn't, this would be a huge security risk, as administrators would be able to access customer data. If you take a memory dump on a storage system you don't get a copy of the cache. They're very much separated.

  4. Pascal Monett Silver badge

    Server-based storage ?

    Um, I know I don't know anything about this part of the industry, but since when has storage not been server-based ?

    I guess it's just the marketing term.

    1. Mr. Twinkee

      Re: Server-based storage ?

      When has storage not been server-based?! Well there are dedicated arrays, JBODs and JBOF storage that have no operating system for users, no on-board compute for processing applications, so there have been and are a lot of non-server-based storage products out there.

  5. Anonymous Coward
    Anonymous Coward

    A couple of months ago, I had an interview with a large gaming company. One of the questions was about SDS. The first words out of my mouth was ViPER, at which point I was interrupted and told I was wrong, he then went on at great length to describe server based storage. This was the same company that think a 10 year old array is cutting edge SDS tech. I couldn't get off the phone quick enough. Pity though, the job was close to home. :(

    1. Nuff Said

      "I was interrupted and told I was wrong"

      He had a point though, since it's spelt ViPR.

  6. Anonymous Coward
    Anonymous Coward

    It makes one wonder how these TLAs get started. Wouldn't Host Managed Storage (HMS) and Storage Managed Storage (SMS) be more intuitive? We all sort of get what is meant by Host and Storage. Or replace Host with Server, oh that wouldn't work!

  7. Anonymous Coward
    Anonymous Coward

    100% Software Defined Storage

    Two True Software Defined Storage vendors (100% SW solution):



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