Unified storage -- sometimes called network unified storage or multiprotocol storage -- is a storage system that makes it possible to run and manage files and applications from a single device. A unified storage system simultaneously enables storage of file data and handles the block-based input/output (I/O) of enterprise applications. To this end, a multiprotocol storage system consolidates file- and block-based access in a single storage platform compared to traditional arrays that contain either one or the other.
A unified storage architecture uses file protocols such as Server Message Block (SMB) and Network File System (NFS), and block-based protocols such as Fibre Channel (FC) and Internet Small Computer System Interface (iSCSI) so users can access consolidated applications and storage.
Benefits and downsides of unified storage
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.
Benefits and challenges of unified storage
Unified storage systems generally cost the same and enjoy the same level of reliability as dedicated file or block storage systems. However, the actual management overhead depends on the full complement of features and functionality provided in the platform.
Because unified storage often limits the level of control in file- versus block-based I/O, this can potentially lead to reduced or variable storage performance. Block-based data tends to require higher I/O compared to file-level data, which is more random and takes a longer time to service requests. For these reasons, mission-critical applications should continue to be deployed on block-based storage systems and not on unified storage.
Major multiprotocol storage vendors and products
Unified storage is evolving to include the cloud and storage virtualization. For instance, cloud provider Nasuni Corp. offers unified file and data storage that combines on-premises systems with cloud storage, which works on object storage, with centralized access.
Other big vendors dominate the block and file unified storage architecture, such as NetApp's Unified Storage Infrastructure that is now cloud-integrated. EMC VNX unified storage is for mixed workloads in physical and virtual environments. The vendor also offers its EMC VMAX product for consolidated, mission-critical applications. Hitachi Data Systems has its Hitachi Unified Storage (HUS) series and HUS VM platforms that use the vendor's own virtualization technology to deploy traditional storage along with object-based storage. The IBM Storwize Unified system works with virtual servers and supports cloud and analytics applications.