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.