Unified storage (sometimes termed network unified storage or NUS) is a storage system that makes it possible to run and manage files and applications from a single device. To this end, a unified storage system consolidates file-based and block-based access in a single storage platform and supports Fibre Channel SAN, IP-based SAN (iSCSI), and NAS (network attached storage).
A unified storage system simultaneously enables storage of file data and handles the block-based I/O (input/output) of enterprise applications. In actual practice, unified storage is often implemented in a NAS platform that is modified to add block-mode support. For example, Dell EMC offers the Celerra Universal IP/FC storage system which offers a unified storage architecture. Numerous other products based on Microsoft’s WUDSS (Windows Unified Data Storage Server) have been configured to support both block and file I/O.
One advantage of unified storage is reduced hardware requirements. Instead of separate storage platforms, like NAS for file-based storage and a RAID disk array for block-based storage, unified storage combines both modes in a single device. Alternatively, a single device could be deployed for either file or block storage as required.