Since there are different interpretations of Software-Defined Storage (SDS), let’s make sure we speak one language and stick to one definition. So, SDS is a way in which software, rather than hardware, defines storage characteristics like performance, availability, and resiliency. Such programs are independent of the physical storage devices, which allows eliminating their limitations. The main goal of SDS is to provide you with a centralized management and efficient utilization of storage resources and the ability to meet specific data requirements.
Now, just to avoid any possible confusion, SDS is not storage virtualization. While some vendors utilize storage virtualization as a part of their SDS offerings, these two terms are not the same. To make it clear: storage virtualization means separating storage capacity from multiple storage devices and presenting it as a unified virtual storage pool. On the other hand, Software-Defined Storage separates the storage capabilities and services from the storage hardware. With that being said, SDS solutions may include storage virtualization, however, it is not a strict law.
Since the appearance of the first tapes and disk drives, IT infrastructure features, such as performance, availability, and resiliency were highly dependent on its physical components. Basically, if you needed more IOPS, you had to add more disks; if you needed lower latency, you had to get faster disks, SSDs, for example. However, there certainly is a limit to how many more disks you can buy and how many more physical controllers you will need for keeping proper system operation. Furthermore, with traditional storage infrastructure, it becomes a challenging task to assign resources to applications based on their specific requirements, hence under- or over-utilization of specific storage resources often occurs. Additionally, managing IT infrastructures consisting of multiple hardware pieces is quite a challenging task for any IT team, not to mention possible interoperability problems.
With Software-Defined Storage, you can start utilizing what you already have much more efficiently instead of buying more disks, as it separates storage characteristics from the underlying hardware infrastructure and delegates them to the software layer. SDS saves expenses on purchasing additional hardware since better performance, data availability, and resiliency are all provided by programs. With SDS, you can manage your heterogeneous storage infrastructure from a single pane of glass and provide your applications with necessary storage and performance requirements.
First of all, Software-Defined Storage provides abstraction of storage characteristics from the underlying hardware. This means that SDS solutions can run on commodity server hardware with x86 processors, enabling cost savings over traditional storage area network (SAN) and network-attached storage (NAS) systems, which tightly couple software and hardware.
With SDS, storage management becomes unified and much easier as all storage resources are pooled together and orchestrated at the OS or Hypervisor layer with the help of virtual storage controllers running on every cluster node. Ultimately, you can provide your applications with all the necessary resources, including compute, memory, storage, and networking, via a single management interface.
By separating the storage hardware from the software layer, Software-Defined Storage allows companies to purchase different storage hardware pieces from various vendors. Thus, SDS breaks the spell of vendor lock-in and eliminates such issues as under- or over-utilization of storage resources and interoperability problems.
One of the greatest benefits of SDS is that it provides your current storage infrastructure with features which were previously unavailable. These include deduplication, replication, snapshotting, server-side caching, and log-structuring across a wide range of server hardware components. To say more, SDS makes your IT infrastructure more flexible. It allows the system to both scale up by simply throwing in more capacity to the existing storage nodes, or to scale out by adding new nodes with their own storage, RAM, and CPUs to increase both capacity and performance.
Probably, the number one scenario where you need Software-Defined Storage is High Availability for mission-critical data. In case of one of your servers goes down, SDS architecture allows shifting load and data automatically to another available node. For example, StarWind Virtual SAN mirrors internal storage resources between hypervisor servers, creating a highly available storage pool and allowing your data to remain available even in case something happens to the node where it was stored.
Another use case for SDS is non-disruptive data migration. By deploying an SDS solution in your environment, you can then use it to virtualize storage volumes on existing and new storage arrays and swiftly migrate data between them. Thus, your applications continue running while remaining unaware that data migration occurs.
As you know, cloud storage becomes more and more popular as it offers a reliable and cost-efficient way for storing your data. That’s where SDS comes in handy. In addition to providing flexible scaling options (scale up/scale out), it can expand your storage infrastructure to the cloud delivering even higher cost-efficiency and DR capabilities.
