Software-defined storage (SDS) is an approach to data storage in which the programming that controls storage-related tasks is decoupled from the physical storage hardware.
SDS places the emphasis on storage-related services rather than storage hardware. It is part of a larger industry trend that includes software-defined networking (SDN). As is the case with SDN, the goal of software-defined storage is to provide administrators with flexible management capabilities through programming. Without the constraints of a physical system, a storage resource can be used more efficiently and its administration can be simplified through automated policy-based management. Potentially, a single software interface could be used to manage a shared storage pool that runs on commodity hardware.
The software-defined storage market is evolving and many storage marketers are still trying to figure out how to associate their products with the label. Although the term is causing some confusion, the consensus seems to be that in order to be considered part of the SDS market, the vendor must provide software that allows the customer to allocate and share storage assets across all workloads, whether storage is virtualized or not.