Is Software-Defined Storage For Real Or A Lot Of Hot Air?

Caught in the crossfire are solution providers and customers who need to separate the hope for lower-cost, more flexible storage from the hype of yet another new IT term that changes meaning from vendor to vendor.

For smaller vendors looking to make their mark in the storage industry, the idea of defining storage services with software independent of the underlying hardware is appealing as it gives them an opportunity to even the playing field with their larger, more well-established competitors.

However, larger vendors that see the traditional close tie between hardware and software as a way to optimize storage services and performance even as they start opening up to the idea of some functionality moving to a software layer, have to carefully tread into the concept of software-defined storage or risk cannibalizing their existing product lines.

While there is no single industrywide definition for software-defined storage, it can be thought of as a software layer that provides storage services, including such functions as deduplication, replication, snapshots and thin provisioning, using industry-standard server hardware.

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Software-defined storage is not storage virtualization. Storage virtualization pools the capacity of multiple storage devices or arrays to make it appear as if it is sitting on a single device. Software-defined storage is not about separating capacity from a storage device, but instead is about separating the storage features, or services, from the hardware.


For Keith Norbie, until recently the vice president Nexus, the Minnetonka, Minn., office of Atlanta-based solution provider Stratos Management Systems, software-defined storage is a combination of trend and hype.

"The whole reason the term exists is to give storage the play the software-defined networking movement has," Norbie said. "The problem is, we already have software-defined storage, but we lack the ability to really define it."

What's missing is the kind of APIs that would make software-defined storage an integrated part of the software-defined data center, he said.

Norbie said to think of the software-defined data center as a Logitech Harmony remote which, when used with a home theater system, controls everything with the press of a button.

"In a way, that's how software-defined everything should be," he said. "One button to do all the automation. Today, no vendor has that technology that works with everything. ... We just lack all the controls for an extra management function. Storage is a component, networking is a component, compute is a component. We have control with compute and networking. Storage will be the hardest one."

Mike Carter, CEO of eGroup, a Mount Pleasant, S.C.-based solution provider, said the true manifestation of this new "software-defined storage" buzz is one in which the entire life cycle of a storage solution, which couples commodity or purpose-built hardware with the traditional storage operating system and data services such as snapshots and replication, is driven by a semi-sentient higher-level software broker and executor.

For instance, Carter said, in VMware’s case, it would include vCenter to automate the creation, provisioning and destruction of storage resources based on policy, performance envelope, duration and utility.

"Advancing storage solutions to this level of 'form follows function' where virtualization, automation, and ease of use do the heavy lifting for the storage layer, integrated heartily into the overall virtual data center framework, will be a key component of a true software-defined data center," he said.


Smaller storage vendors, especially startups, are quick to say that software-defined storage is already a reality.

Jerome Lecat, CEO of Scality, a San Francisco-based developer of scale-out storage technology, defined software-defined storage as a platform built from x86-based servers where all the intelligence and storage-specific capabilities are provided by software.

"With software-defined storage, the storage is not in an array," Lecat said. "It's in servers and disks. We're not using any arrays."

Lecat said the storage industry has been talking about software-defined storage for years even if the term was not yet used.

"We talked about this for three years," he said. "In 2011, I had to use long sentences to describe it. Now, I say 'SDS' and people get it."

Joe Arnold, CEO of San Francisco-based startup software-defined storage developer SwiftStack, also said the term makes it easier to describe what companies like his are doing.

"A year ago, we had trouble describing what we do," Arnold said. "We said we were decoupling our controller from the underlying hardware. Then we heard the term, and it clicked."

Software-defined storage is a way of looking at storage not from the disk or flash perspective, but rather in terms of what storage services are offered separate from the hardware, said Steve Houck, COO of DataCore Software, a Fort Lauderdale, Fla.-based developer of data management and protection software.

Storage used to be seen in terms of disk capacity, hardware and speeds, Houck said. "With software-defined storage, we look at it from the software layer and the value it presents on the hardware, he said. "It's very much about looking at storage from the device level or virtualization level."


While startups and smaller software-focused vendors say software-defined storage is a way to replace legacy storage hardware with commodity hardware, storage hardware vendors are not giving ground in terms of the value their hardware offers as storage functionality moves toward the software layer.

For storage giant EMC, the push is on to define its software-defined storage strategy while ensuring the company minimizes the potential impact on its existing storage technology business.

Amitabh Srivastava, president of advanced storage at EMC, said customers will be looking to cut management costs even as they look for increased storage automation, and will be seeking flexibility in vendor choice and how capacity is acquired.

"We have to pause and rethink how data is stored, and how it is managed," Srivastava said.

EMC's definition of software-defined storage includes capacity that is scalable across multiple geographies, and across commodity servers or on EMC or third-party arrays, the ability to virtualize all the underlying storage into pools, and open APIs so any vendor, partner or customer can build the controllers needed to access the underlying storage hardware, Srivastava said.

Because of EMC's storage software capabilities and its commodity x86 server-based hardware, the company has an advantage over software-defined storage startups that can provide only parts of the entire infrastructure, Srivastava said.

By making its APIs openly available, EMC can be at the center of the software-defined storage movement, he said. "Building a product is not enough," he said. "You need to build a community. ... We're opening up APIs so new services can be built by partners or customers."