In-Depth

Clearing the Storage Confusion

The blurring lines of storage and the industry terms used can leave enterprises evaluating their next storage buy puzzled. Here's a look at three phrases you need to know.

• By Scott D. Lowe
• 04/23/2014

I've said before that I think that storage is a pretty exciting space right now, but that excitement comes at a cost. Specifically, with so much opportunity in the market comes the potential to seriously confuse buyers about what is available and how it all works. Personally, I've seen some of this confusion at client sites and it gets worse every time a vendor decides to remarket themselves using the latest entry in Buzzword Bingo.

So I'm going to attempt to provide some guidance about what three common terms mean and how you can use them to help improve your next storage purchase:

Software-Defined Storage
Simply put, software-defined storage (SDS) is that which doesn't require hardware. If you're asking yourself exactly where you'll save your stuff if there's no hardware, that's a really good question! With most companies selling their wares under the SDS name, there are one of two paths that are chosen:

• The SDS vendor bundles hardware with their solution. In these cases, the hardware is usually commodity gear aimed toward keeping costs reasonable. The hardware itself is pretty much interchangeable with other hardware. The SDS vendor's software simply sits atop this hardware and manages the storage environment.
• Customers "bring their own storage" to the software. In these cases, the customer buys just the software and they add their own hardware to the mix. The hardware must be supported, so most vendors that choose this path provide some kind of compatibility list that can help narrow down the selection.

Software-defined storage is just one element of the emerging broader software defined data center. How do you tell if a solution is software-based? If the software element can stand alone and be applied to any reasonable hardware combination, it's software-based.  If there are custom-engineered chips and specialty hardware required, it's not software-based.

Hyperconverged Storage/Server
However, on the way to SDS, some vendors kind of sidetracked and discovered that they could create an entirely new class of infrastructure in the modern data center. There are the vendors sell solutions often referred to as hyperconverged, natively converged or server SAN solutions. In short, they take the SAN and existing virtualization hosts out of the data center and replace them with appliances that handle both the compute and the storage functions. So, inside this highly converged appliance lie all of an organization's virtual machines as well as the company's data. These solutions almost always require at least three such nodes in order to achieve data protection goals.

These solutions are almost always scale out in nature (maybe link to my previous scale out vs. scale up post?) and are an emerging way for companies to construct their data centers.  Rather than rely on complex legacy servers and storage, the vendors in this space embrace the simplicity of their all-in-one solution.

Hybrid Storage
In the old days, hard disks were the only way to reasonably store data. Today, with the rise of flash storage, new opportunities have arisen. Hybrid storage is one of these opportunities.  In a hybrid storage system, vendors provide a mix of flash storage and hard drives so that customers get both performance and capacity needs met. The flash storage addresses speed while the hard disks address capacity. By buying hybrid, you don't need to go to the expense of all flash, but you don't have to suffer with just hard drives, either. There are a number of startups in the hybrid space and tier-one storage vendors are now providing their own hybrid solutions to meet market demand.