Software-defined storage: Making sense of the data storage technology
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There are a few soft spots in the arguments that so-called software-defined storage systems will somehow be able to erase the requirements of the underlying hardware.
You're now reading an SDC, software-defined column. Hey, why not? It seems that everything in IT is software defined these days, so a software-defined column doesn't seem so farfetched. And all this software-defined stuff showed up just in time -- poor old hardware has been shouldering the entire load all these years, so it's going to be a relief to let software take over.
Software-defined storage, software-defined networks, software-defined security … and software-defined software can't be too far off. If you believe all this software-defined hype, you'd think hardware has been ruling the data center on its own all this time. And you might think software was just invented.
The truth is that marketing is once again muddying the storage waters. Depending on how you look at it, there's no such thing as software-defined storage or storage has always been defined by software. The hype machine is running full tilt with this one; maybe the big data express has finally run out of steam? What started out as a how-to-beat-the-big-storage-vendors-and-save-tens-of-thousands-of-bucks gambit now has the entire storage market singing the software-defined anthem, even the big guys that this "movement" was supposed to challenge. Now it seems like every vendor out there has a product that will allow storage shops everywhere to throw off the shackles of hardware dominance.
So what's wrong with this picture? Simply that storage has always been about software. The hardware is just a box of tiny switches, gates and pipelines the software uses to identify data, move it around and finally stick on another piece of otherwise inanimate hardware that's little more than a magnetized platter.
But a growing cadre of vendors is pushing the idea that you don't need clunky old hardware, that you can create storage systems out of software. Now that would be the epitome of virtualization -- creating storage systems without actually using … er … storage.
They're not claiming you don't need some disks or flash chips to have a place to actually store your data. And they acknowledge that some computing power will be needed to give their software a home and kind of run things. And you'll probably want some kind of network interface unless you don't plan to have more than one app using your storage. And you'll need some cables, of course, and some power and cooling, and maybe a rack to hold all this stuff in place.
Hmmm … it looks like you'll need an awful lot of hardware to make this software-defined storage thing work.
I might be exaggerating a little here, and perhaps the vendors aren't really suggesting that their software will do away with the need for hardware. But remember that storage still means hardware, and that hardware will always need maintenance, supervision, and proper care and feeding. And that's going to take some time and require some specialized skills, no matter how virtualized the environment is or how distant the software makes the hardware appear. To think that a piece of software will somehow erase the requirements of the underlying hardware is, at best, an exercise in delusion.
There are a couple of other soft spots in the arguments we hear for so-called software-defined storage systems. First, they all seem to expect that we all have piles of disk drives and JBODs just sitting around waiting to be used. If we do, they're probably sitting in heaps because they're old, slow energy drainers with less capacity than your iPad.
The other loopy selling point is that you can cobble together your own sophisticated storage systems with these software products. There's no question it can be done, but who really wants to march into the corner office to tell the boss that the DIY science project is ready to host the company's critical apps?
Another key selling point seems to be the "advantage" of running your storage system off a virtual machine (VM). I'm not so sure that running your storage system on a VM is such a great advancement for shared storage. But that way, if your server iron quits, you'll lose all your VMs and your storage. At least you'd have a very efficient disaster.
Some vendors position their products as virtual or virtualized storage appliances, but how much they're actually virtualizing the storage might be a little questionable. And it's hardly new; companies like DataCore and Sanbolic have been doing host-based storage virtualization for years.
No matter how much we want software to help us not to worry about "things," when it comes to storage, the thing is the thing. So, how about some sanity-defined storage for a change?
About the author:
Rich Castagna is editorial director of TechTarget's Storage Media Group.