Network-Attached Storage (NAS) is simply shared storage connected to a network. NAS devices can store and share data for multiple heterogeneous computers, regardless of the architecture or operating system (Linux, Mac, Unix, Windows). NAS devices let you store and access files from a central, secure location, regardless if you are on the same network locally or remotely over the internet using a variety of file-based protocols, AFP (Mac), NCP (NetWare), NFS (Linux/Unix), SMB/CIFS (Windows). NAS servers simply act as a shared volume for backup up and sharing files across a network, and can be used to share other peripheral resources, such as an archive library, IP cameras, multi-media, printers and more. The simplicity, ease of installation, configuration, management and operational features are the main attractions for traditional NAS.

Three key factors of every NAS core component, the magnetic/hard disk drive (HDD), is selecting the correct drive type (SSD/SAS/SATA) for your application, the number of drives and reliability of that drive in relation to the anticipated application workload, and the inherent security features.

Traditional NAS servers are comprised of one or two controllers, a preset amount of cpu/memory/drive-slots, and have a fixed storage capacity, or known as scale-out NAS. Once storage capacity has been maximized, you must purchase another separately managed NAS system to increase capacity and performance. Scale-out NAS systems can expand to store many petabytes of data by simply adding clustered storage nodes, typically x86-based servers that are administered as a single system through a global namespace or distributed filesystem.

The evolving features and capabilities of NAS servers has been driven by the ever-accelerating growth of unstructured data, continued IT virtualization and extended file services to meet both Cloud computing and mobility client demand. Scalable NAS subsystems continue to evolve to meet the latest accessibility, capacity and management needs. Many organizations are adopting a mixed/hybrid approach to meet their storage needs to leverage the combined benefits of cloud storage and NAS to enable continued local control and possession of their data (NAS), while providing consistent data access from any location (cloud). The quickly fading boundaries between personal computing and the workplace require NAS systems to be easily yet securely accessible from a plethora of devices. Scalability, accessibility and manageability are the key areas that next-generation NAS solutions will be measured.  Salient features of next-generation NAS include:

Scale-out Architecture > Ability to proportionately scale performance and capacity as nodes are added with simplified management as a single storage pool

Single Management pane > Real-time status monitoring and actionable analytics for automated, rules-based event response

High-availability > Ability to sustain multiple, concurrent failures with self-healing characteristics

End-point Support > Improved integration and support of mobile/tablet devices for simplified/secure data access

Cloud Support > Ability to add Cloud as an additional storage tier for scalability

Object Storage Features > REST protocol/metadata support for NAS-based Cloud storage

Automated Tiering > Ability to automatically relocate data for increased performance, lower TCO and scalability

Representative State Transfer > REST is a stateless protocol enabling client access to server-side data via HTTP

NFSv4 > Support for clustered/scalable parallel access to files distributed across multiple nodes (pNFS)

HADOOP FS Support > Support for HDFS, a JAVA-based distributed, scalable, portable file system