What is Software-Defined Storage?

11-05-2021 |   |  By Robin Mitchell

The concept of software-defined stuff is becoming increasingly popular with software-defined cars and software-defined networking making the news. However, another term that is beginning to rise is software-defined storage, but what exactly is it?

What is Software-Defined Storage?

After coming across the term for the first time, actually finding out what software-defined storage was not trivial, and it appears that the term “software-defined storage” is a bit of a marketing buzz word similar to IoT. When the term IoT came out, it left me confused as it sounded like a new paradigm of programming and device that somehow existed in their own bubble, but the truth was that IoT devices were simply, wait for it, internet-connected devices.

Depending on where you research, Software-Defined Storage, or SDS, will be described as a scalable solution that enables platforms to utilise open-source software and off-the-shelf hardware to create a storage solution that can save money and enable software systems to interact with storage intelligently. Now, for the real definition of SDS!

Software-Defined storage, simply put, is a storage solution that provides advanced storage mechanisms, but these mechanisms are defined in software. Another way to think of it is replacing drive controllers with software. For example, RAID controllers allow for drives to be used in different configurations, but an SDS would remove the RAID controller, and implement this function in software instead.

What advantages does SDS have?

So, it is clear that SDS is something that must be important because there are major players such as IBM who are investing in SDS, but what advantages does SDS provide? The first advantage offered by SDS is that by removing dedicated hardware controllers there is no need for purchasing of specialised hardware. This means that a RAID drive system can be constructed from off-the-shelf parts which can be a more cost-effective solution.

The second advantage presented by SDS is that by removing the need for dedicated hardware controllers, systems can be more easily expanded. For example, a RAID drive whose purpose is to backup data can only work with so many drives. If more storage is needed, then a new RAID system may be required, including the cost for a new case, disks, and RAID controller. Furthermore, the software is still needed to tie the two separate RAID drives together. HOWEVER, an SDS can work with as many drives that can fit on a network, and the software controls the way these drives are handled.

The second advantage carries onto the third advantage of SDS; reconfigurability. A drive system controlled in software instead of hardware can be configured in many different ways, and these can be upgraded over time. If a RAID controller is found to contain a bug or limitation, simply using a new RAID controller may not be an option. 

The fourth advantage of SDS is the ability for targeted storage. Storage varies in technology and size greatly, with hard disks being ideal for storing large files that are often accessed while tape drives are ideal for large backups. However, the result of these different abilities is varying costs, and as such, trying to manage data storage depending on cost is complex. An SDS would instead be able to automatically route data to store it on the most economic system depending on its access rate and type.

Who is involved with Software-Defined storage?

A range of different service is developing SDS systems provides in the IT and computing field. IBM is one contender that provides SDS solutions for a wide range of different applications including AI, big data, and servers. IBM has delivered SDS solutions and services to multiple clients with The University of Queensland and Coventry Building Society being two examples. 

Dell is another company that offers SDS solutions for clients with the use of their Dell EMC ECS. According to Dell, the EX range is scalable storage racks that integrate hardware and software with bays usable with SSDs and HDDs. Furthermore, the use of such racks can enable the use of SSDs as metadata cache that is required frequently while using HDDs for storage of larger files that are less frequently accessed.

The SDS industry is still in its infancy, and the advantages of SDS are still to be realised. However, the ability to replace the hardware with software does present real advantages. The question now is if this concept can be transported to the consumer sector and find its way into everyday computing devices.

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By Robin Mitchell

Robin Mitchell is an electronic engineer who has been involved in electronics since the age of 13. After completing a BEng at the University of Warwick, Robin moved into the field of online content creation developing articles, news pieces, and projects aimed at professionals and makers alike. Currently, Robin runs a small electronics business, MitchElectronics, which produces educational kits and resources.

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