Software Defined Storage (SDS) abstracts the storage software from the storage hardware. It sounds great on paper and looks great on the whiteboard but in execution it fails to impress. Storage Switzerland finds that the large majority of customers still buy their storage systems as an integrated system, not as two separate components, despite the intrinsic advantages that SDS seems to deliver. We find the state of SDS so bad that many SDS vendors are running away from the term, which we also think is a mistake.
Vendors Are Using SDS
Vendors who provide turnkey systems use an SDS model for software development so they can quickly move to new hardware platforms; they just don’t pass that flexibility on to existing customers. It makes sense that when a customer gets started with a new storage infrastructure, they’d want a turnkey system for a seamless deployment and to reduce finger pointing in case something goes wrong. After a few years of successful operation, it seems that most customers would appreciate the flexibility of moving to different hardware, either for a price advantage or to move to a hardware platform, that is more quickly embracing a new hardware technology. Most vendors don’t provide that flexibility though.
Why Don’t Customers Want SDS?
The primary reason that most customers don’t embrace SDS is there is a perceived complexity to SDS adoption. Some of this perception is justified. Many SDS vendors very carefully curate the hardware they support. Part of this curation is to ensure a quality customer experience and part is to make sure that the hardware is powerful enough to drive the software. While in theory SDS claims “any hardware”, it is seldom the case. There are, however, a handful of SDS solutions that can support a wide range of hardware options and even some carefully curated SDS solutions that offer still more flexibility than most vendor provided SDS solutions.
If the thought of buying hardware and software from different vendors seems to daunting, then most SDS vendors do have the option of delivering a turnkey solution to their customers. The advantage is that customers can then intermix other hardware solutions as the need arises. The advantage that SDS provides is the license isn’t tied to the hardware. With most vendor solutions, upgrading to new, more capable hardware also means buying new software since the licenses aren’t portable. With SDS, the software license is typically portable between hardware platforms.
Another reason that customers tend to avoid SDS is that there is a perception that SDS solutions don’t offer the same feature set available in solutions from enterprise storage vendors. There was some truth to this perception, especially in the early days of SDS but today’s SDS solutions offer very complete solutions and, in many cases, offer more capabilities than their counter parts. For example, they can easily migrate data between different storage systems and some can tier data between storage systems. Additionally, many of them leverage their software roots to run in the cloud, meaning that they can leverage the cloud as a replication DR target or migrate workloads into the cloud for cloud bursting or migration.
Why You Want SDS
We’ve alluded in the above section, to some of the reasons you want SDS. First, is hardware flexibility. It does not mean that the organization should start buying the cheapest hardware it can find but it will typically find that stand-alone server or storage hardware, without the software, to be dramatically less expensive than turnkey solutions from major vendors. Again, that software license is portable between hardware, so the moment the next generation of PCIe or NVMe comes out, the organization can immediately move to it.
Another reason to embrace SDS goes beyond saving money. SDS provides capabilities that turnkey vendors are highly unlikely to provide. The ability to migrate data easily between systems, snapshot to other systems and burst to the cloud are just a few examples.
A final reason, not discussed yet, is the compatibility with a subscription model bringing to the on-premises data center the same business model as the cloud. The challenge for turnkey vendors is because they are so locked into their hardware bundles it is difficult for them to deliver a true subscription model. SDS vendors can easily provide a subscription model and organizations can now find hardware vendors that also will provide hardware on a more operating expenses (OPEX) basis. In our opinion, it makes sense to buy the hardware the organization knows it needs, and subscribe to the SDS solution of their choice but then have the flexibility to change out or upgrade hardware as it makes sense.
The state of SDS is shaky. Organizations have not adopted it for a variety of reasons but SDS vendors have addressed most of those reasons. Today, SDS provides organizations with an easy startup cycle thanks to turnkey agreements plus long-term flexibility as their confidence in the selection increases. SDS, also, in many cases, provides better features than turnkey solutions while also opening up new possibilities in terms of a business model.