A Microsoft software-defined storage architecture for Windows 10 and Windows Server, starting with Windows Server 2012 R2. Storage Spaces are virtual storage drives that are created after two or more drives are grouped together as a storage pool. They offer protection from drive failure and make it easier to add storage when required.
Storage Spaces can be configured like RAID arrays. For example, Simple Spaces uses two drives to increase performance (RAID 0), and Mirror Spaces uses two drives for data redundancy (RAID 1). Parity Spaces uses three drives for speed as well as protection against a drive failure (RAID 3). See RAID
Storage Spaces Direct (S2D)
Starting with Windows Server 2016, Storage Spaces Direct extends storage pools from only one server to a cluster of two to 16 servers. Each server in the cluster has its own storage but the entire storage pool is available to all of them. See software-defined storage