Software-defined storage: Making sense of the data storage technology
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IT pros have been juggling hardware and software decisions for years, struggling to find the right balance between the two. It's a simple equation that can be hard to resolve: The hardware should enhance the software it hosts, and the software should be able to take advantage of all the features the hardware offers.
Ironically, storage vendors were the unlikely saviors, as they did the hardware-software tailoring to ensure both worked reasonably well together. But that service came at a price: dreaded vendor lock-in. The software ran great, the hardware hummed, but they only harmonized if you bought them from the same vendor.
That was nothing new, however, and most IT veterans had gotten over their fear of getting locked into a specific vendor many moons ago. Vendor lock-in? Just a fact of IT life.
Hardware-software tug of war continues
So along come software-defined storage products and software-defined just about everything else. Software-defined storage (SDS) has been positioned as the remedy for those tightly linked hardware-software combos -- the answer to vendor lock-in, chewing up and spitting out proprietary hardware to set data centers free along the way.
Expectations have been high for software-defined storage products. Decoupling storage software from specific hardware components should mean greater freedom and lower costs, right? In some cases, it has, but in others ...
Vox populi: The good and bad of SDS
A recent survey fielded by DataCore Software, an early entrant in the storage virtualization market that morphed into SDS, offers some insights into SDS buyers' expectations in the latest edition of its annual market survey.
Server virtualization is typically the first step toward a more broadly virtualized data center, but it can also expose new infrastructure weakness, according to DataCore's survey. Interestingly -- and contrary to the hyper-converged party line -- 31% of the survey's respondents said virtualizing applications required shared storage to ensure high availability. Similarly, 29% found application performance dropped after virtualization, and -- not surprisingly -- 29% also said figuring out the best storage setups for their apps became more difficult.
Still, users hold out a lot of hope for software-defined storage products. Fifty-five percent of DataCore's survey takers expected that SDS would make managing storage simpler; 53% said it might "future-proof" their infrastructures; 47% hoped it would extend the life of already installed storage resources. The lock-in issue surfaced in the survey, too, with 52% counting on software-defined storage products to help their shops avoid getting locked into a single vendor's products.
What's fascinating about those results is that some users seem to think their hardware won't age if everything lives in a software-controlled world.
SDS appliances: Irony or big iron?
Just about every traditional storage vendor and a whole slew of startups offer software-defined storage products. And most of them sell their software on -- you guessed it -- hardware that they've either built or certified themselves. So while the software might have been decoupled from the hardware, the two aren't exactly divorced. Hmm, sounds a little like vendor lock-in, doesn't it?
In addition, although software-defined storage products that are more SAN server than hyper-converged infrastructure (HCI) exist, most people equate software-defined with the latter. And, again, according to DataCore's survey, expectations for hyper-converged are high. Nearly half of respondents (48%) sought simplified management in HCI, while scale-out expansion (39%) and reduced hardware costs (35%) were also key considerations.
There's no question, successful HCI implementations far outnumber disappointments, and scalability and easier management are real. Cutting hardware costs could be a bit tougher to realize, however. SDS vendors may be shipping appliances based on cheapo white box servers with Fry's bargain-shelf components, but these are top-of-the-line, advanced server systems with top-notch parts. If the software is going to do its job right, it needs a solid platform on which to perform. And those high-end, certified, tested and preconfigured servers can end up on the expensive side compared to the phrase "commodity server" that often gets tossed around in HCI discussions.
Your apps define your storage
Lately, a lot of the focus about data center infrastructure has shifted from "storage" to a more data-centric model. But that's not really anything new to storage pros. Anybody who's been around controllers, hard disks and solid-state drives for a while knows storage isn't just a resting place for a bunch of bits, but matching storage to the explicit needs of an application is where the artistry emerges. So whether the answer is SAN, NAS, object or software-defined storage products, the bottom line is the care and feeding of company apps with the right type and amount of storage.
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