SDS is software-defined storage, where resource management is abstracted from the underlying physical hardware.
SDC contains a software layer on top of the underlying physical infrastructure, allowing management and allocation of virtualized resources: processing power, storage and networking. This distinguishes it from traditional SAN and NAS storage systems.
Common features of SDS solutions include the ability to aggregate storage resources, scale to cluster servers, and manage services and storage pools through a single interface.
Software-defined storage is part of hyperconverged systems, which also include software-defined networking (SDN), software-defined infrastructure (SDI) and software-defined data centers (SDDC).
In vStack SDS it is an equally-defined storage layer that uses resource primitives from the cluster layer.