A storage node is typically a physical server with one or more hard-disk drives (HDDs) or solid-state drives (SDDs).
A storage node can also be a virtual machine or virtual LUN with access to one or more HDDs and/or SSDs. Virtual storage nodes have historically been less common due to the potential consequence of unpredictable performance and latency. The emergence of virtual storage area network (VSAN) technology has led to an increase in the use of virtual storage nodes.
A collection of storage nodes is often clustered together and managed through software as a single pool of storage. One of the main advantages of a system that uses multiple storage nodes is data availability in the event of a component failure. If an HDD or SDD or a storage node fails, the system is able to continue to deliver data from the working nodes.