A lot has been said regarding “what is software-defined storage” (SDS). It has become an overused buzzword. Naturally, a lot of software-defined storage vendors try to use it for marketing and PR purposes and announce their existing or slightly modified offerings as “software-defined”.

Some vendors have been especially blunt by trying to trick the customer to buy the complete opposite of SDS, but in shiny marketing “SDS wrap”. Fortunately, most customers don’t do it.

So let’s dive into it: what is software-defined storage:

• SDS is building a storage system from standard hardware (servers), with all storage functionality delivered by intelligent storage software. The hardware used should be coming from a particular vendor, i.e. the components used should be interchangeable and widely available on the market. Still, there are best practices when building SDS systems and components are carefully selected for the task, although they are all standard CPUs, RAM, NICs, HBAs, HDDs, SSDs, switches, etc.
• The total solution must provide the full functionality with just software and must not be dependent on an external specialized storage system. The whole intelligence comes from the storage software.
• Autonomy and redundancy on a system level – a distributed storage system, which aggregates the capacity and performance of the standard hardware.  
  

And since some vendors are doing “marketing-defined storage”, let’s cover what Software Defined Storage IS NOT:

• “Orchestration”, “storage virtualization”, etc. – if you need another layer of legacy technology underneath – do NOT use SDS.
• Software-managed is not Software-defined – two SAN boxes managed by a piece of software.
• Integration and ecosystem support – connecting your SAN to VMware, OpenStack, etc. don’t make it “software-defined”.
• Silver bullet – SDS will not solve all of your problems.

There is a wide misconception that any hardware will work with software-defined systems. While this is true to some extent, like anything in life, there are “dos” and “don’ts”. In practice, Software-defined technologies are sensitive to hardware, configurations, firmware versions, etc. Thus customers should abide by the recommendations and best practice guides of their SDS vendor of choice.

Why would anyone care – what are the challenges which SDS solves?

There are a couple of master trends that ultimately drive the switch to SDS software:

• Exponentially growing data – data is growing, so fast that the current storage solutions cannot keep up with it – their design is rigid and does not have the flexibility and scalability needed or this scalability comes at a prohibitive cost.
• Competition and pricing pressures – businesses are always on the hunt for innovations, which will reduce their cost of business and SDS provides significant cost advantages. We’ll get back to this later on.
• New business reality – because of pervasive adoption of internet and mobile technologies business demands have changed dramatically over the past few years – skyrocketing amounts of data, social and local, big data, real-time analytics, increasing speed and availability demands.
• Advance in technology – commodity servers became powerful enough to replace specialized devices (like storage arrays, switches and others). Powerful multi-core processors – parallel computing, networks with sufficient bandwidth, advance in software – recent research on distributed systems and related technologies.
• Increasing complexity –the above is leading to systems that become increasingly more complex, the margin for error becoming narrower and the consequences of potential failures or more severe
• Storage became the bottleneck – “Over the past 20 years, microprocessor technology—which plays a key role in data storage efficiency and function—has enabled CPU performance to nearly double every 18 months. Put in another way, CPU performance has increased 16,800 times between 1988 and 2008, but HDD performance has increased just 11 times.” [3]

You’ve noticed that the above master trends presented several considerate challenges. And what is software-defined storage – it is a sensible solution to address these challenges.

Why use SDS?

1. It is a better technology in terms of scalability, flexibility, performance, reliability, business agility.
2. It Reduces cost across the entire IT stack – and this is TCO – Total Cost of Ownership, not just storage.
3. To simplify things all the way – from buying hardware and installation through migration, support and ongoing maintenance to upgrades of the storage system.

Market developments and practical advice on buying SDS

The good news is there are a few very good SDS products that deliver excellent performance, reliability and considerable cost reductions (70-80% and in some cases even more).

As a new technology SDS was initially picked up by the so-called “innovators” and “early adopters”. These are usually companies who understand technology and IT is their main line of business. These companies are the first to adopt SDS, because they have the skills (technical personnel) and understand the benefits but also the majority of their budget is on IT, thus the cost reductions are sizable and immediate. To list a few sectors in this domain – cloud service providers, xaaS companies, hosting companies, managed service providers, IT companies, etc.

The next wave in SDS adoption is wider adoption by enterprise non-IT businesses, who have sizable IT – Banks, Insurance companies, Telecoms, Pharma, Automotive, etc. These companies are less tech-savvy and more risk-averse but add scale to the market growth of SDS. We are already seeing adoption in this domain. The last companies to adopt SDS would be the smaller businesses as they do not have the resource nor the knowledge, although we are seeing this market segment is best suited for hyper-converged solutions, rather than SDx solutions.

Another consideration is choosing the right tool for the right task – there are countless of storage use cases and needs, and customers should define their case and need very well before going on the market – so they need a block, an object of file storage? How much (raw, usable, logical)? How much performance will they need, in quantitative measure – TB, IOPS, MB/s, etc. Mind that there is no “one size fits all” and no single solution can deliver on all requirements.

For example, solutions which deliver “unified storage” (block, file, and object, in one solution) usually are not excelling in either. Although this is a pity, it is a fact of life – and to illustrate it with an analogy: a truck which is also a sports car does not make either a proper truck nor a proper sports car. This means that although software-defined storage solutions can reduce the complexity in the data center, larger customers might need more than one solution for different workloads.

More good news: there are excellent SDS solutions for most cases, however customers might have to research which are the best alternatives for their case.

If you have any questions feel free to contact us at info@storpool.slm.dev