A network-attached storage filer (NAS filer) is a file server with massive storage capacity; the devices are designed for backup, archiving and sharing Ethernet connectivity. NAS filers are also known as storage file servers, storage-area network (SAN) filers or storage filers.
NAS filers add scalable, expandable storage for file-serving purposes in data sharing, cloud applications, Internet and enterprise networks, Fibre Channel (FC) SANs and Ethernet local-area networks (LANs).
As SAN/NAS convergence has progressed, devices have gained flexibility and capabilities. Examples include FC SANs with NAS devices plugged into them to enable block storage and file storage, and full NAS gateways with Fibre, SCSI and iSCSI communication (and prices up to a hundred thousand dollars). FC over Ethernet (FCoE), which encapsulates SCSI and block commands into IP packets for transmission over an Ethernet connection, make it possible for SANs to operate within a LAN.