Network-attached storage is a dedicated disk storage subsystem residing on a local-area network (LAN) that provides access to entire files using the CIFS (Windows) or NFS (Unix) protocols. NAS impacts LAN traffic and is generally seen as a solution for smaller businesses or remote offices that want to access whole files.
A storage area network (SAN) addresses essentially the same challenge as a network-attached storage system—allowing server access to a shared pool of data storage.
Network-attached storage (NAS), storage-area networks (SANs), and unified storage provide storage capacity not directly attached to servers but use different protocols for data.
Unified storage, also known as multiprotocol storage, is a single data storage system that supports both file and block access. The subsystem can support NAS (file-based access) as well as iSCSI and Fiber Channel (block-based access) storage protocols simultaneously.
Network-attached storage (NAS), storage-area networks (SANs), and unified storage (a combination of NAS and SAN approaches) have a common element: they provide data storage capacity that isn’t directly attached to servers. They pool storage on arrays of drives that are accessed by and independent of servers.
NAS, SAN, and unified storage differ depending on the network structure that servers and data storage use to connect to each other, as well as on the networking protocols each technology uses to deliver and receive data.
