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There are, to be sure, both pros and cons to software defined storage. Among the benefits of SDS, it can bring flexibility, openness, and also lower costs. However, software defined storage's distributed nature can be challenging for new operators and complexity can creep in.
Pros and Cons of SDS: the Pros
There is no doubt that software defined storage (SDS) has gained serious traction in recent years. Since its introduction less than a decade ago it has steadily overcome technical hurdles and grown in market share. Its attractiveness, after all, stems from the promise it holds.
“One of the big benefits of software defined storage is the flexibility it offers, including the ability to configure and deploy storage systems your way such as the type of hardware, or on virtual, container or cloud platforms,” said Greg Schulz,” Greg Schulz, Senior Advisory Analyst Server StorageIO, and author of "Software Defined Data Infrastructure Essentials."
This means IT can utilize existing hardware rather than having to buy a whole new set of hardware to add functionality. This not only extends the life of existing storage assets, it also helps to avoid hardware lock-in and lowers the total cost of ownership compared with other types of storage. But there are many more advantages to software defined storage such as future proofing of IT assets, far greater scalability, improved performance and overall agility.
“Software-defined storage is all about flexibility, openness, and cost: users have the flexibility to select industry standard x86 server and disk hardware and programmatically define a menu of storage services for tenants to consume,” said Irshad Raihan, Senior Manager, Red Hat Storage Marketing. “These services should be self-service, provide a variety of interfaces (block, file and object), and cater to a range of performance, durability, and availability requirements.”
This is made possible by the decoupling of software from the underlying hardware. For a long time, this was not something traditional storage users could enjoy. The storage services provided were fixed to the hardware infrastructure. Raihan noted that SDS users typically save money by virtue of their ability to select the hardware they need, when they need it, and from whom. The ability to remain open with vendor selection also means a lifecycle that is free from proprietary control and an ecosystem that is broader. Proprietary vendors, startups and the open source community compete on an even playing field based purely on functionality.
“In addition, users can implement rolling upgrades for storage without application downtime or disruption to the business,” said Raihan.
Pros and Cons of SDS: the Cons
But all is not rosy when it comes to SDS. There are advantages and disadvantages to software defined storage. Among the challenges of SDS are integration headaches, the need to take care of an additional layer of software, and having to shift to an SDS culture within the organization. Storage managers gain familiarity with the traditional way of setting up an infrastructure. Inevitably, changing the way they do things is going to cause some confusion.
Schulz cautions that some SDS solutions remain dependent on specific types of hardware. Interoperability, too, can be an issue. Despite being touted, as hardware-independent, some SDS platforms require hardware taken from the hardware compatibility lists (HCL) of certain vendors.
SDS still requires hardware somewhere from someone not only to support the storage functions but also to run the SDS software stack or storage application,” he said. “There is also a common theme of using cheap, low-cost hardware to run your SDS software stack, however be careful that you do not create a low performing storage solution as a by-product. Watch out for trying to cut costs so much that you compromise and cut service levels or availability.”
Those enamored with the do-it-yourself aspect of SDS should consider how much time they really want to spend tinkering with and optimizing their environments. By leveraging a pre-engineered and pre-integrated solution, they can often save time in service and support.
On a similar theme, Raihan worries about the roll out of SDS when IT departments are asked to do a lot more with a lot less. With fewer storage veterans around, and the presence of more IT generalists, the challenges of SDS can sometimes outweigh the benefits.
“Most SDS systems are distributed, and distributed systems can sometimes be more challenging for new operators,” said Raihan. “A single localized system can be easier to operate, but a federation of localized systems is often indistinguishable from a distributed system.”
Complexity tends to creep in along with scale. As a consequence, more skilled operators are generally necessary as SDS becomes more pervasive. Take the case of hyperscale cloud providers: they generally have extraordinarily talented people delivering high efficiency in terms of humans per petabyte. This means that with the power, sophistication, and flexibility enabled by SDS, there comes a responsibility to understand what it can do and how.
At Red Hat, for example, the company emphasizes training and consulting for people implementing its storage in an SDS environment. That way, the inevitable teething problems can be smoothed out along the way.
“We encourage formal knowledge transfer via one of training courses for the staff that will be using Red Hat Storage long-term, as well as assistance from consulting services to ensure architectural needs are met and projects are kicked off properly,” said Raihan.
Software Defined Storage: The Pros Outweigh the Cons
Any new software implementation project is going to run into issues. SDS should be looked upon, then, as a software rollout. Expect bugs to crop up, updates to be required and integration challenges to occur. That is the way it has always been in the software world. SDS is really no different –except it may open the door in the long term to the key advantages of software defined storage: flexibility, agility, hardware independence, tighter integration, scalability, higher performance and lower costs.
In conclusion, then, there are both pros and cons involved in implementing software defined storage. But for many, SDS benefits outweigh the inevitable challenges.