What is Network Attached Storage (NAS)? | IBM

Network attached storage (NAS) is a centralized, file server, which allows multiple users to store and share files over a TCP/IP network via Wifi or an Ethernet cable. It is also commonly known as a NAS box, NAS unit, NAS server, or NAS head. These devices rely on a few components to operate, such as hard drives, network protocols, and a lightweight operating system (OS). 

• Hard drives or hard disk drives (HDDs): HDDs provide storage capacity for a NAS unit as well as an easy way to scale. As more data storage is needed, additional hard disks can be added to meet the system demand, earning it the name “scale-out” NAS. More modern systems leverage flash storage in combination with HDDs or as a standalone configuration. The use case for the NAS device usually determines the type of HDD used. For example, sharing large media files, such as streaming video, across an organization requires more resources than a file system for a single user at home. 

• Network Protocols: TCP/IP protocols –i.e. Transmission Control Protocol (TCP) and Internet Protocol (IP)—are used for data transfer, but the network protocols for data sharing can vary based on the type of client. For example, a Windows client will typically have a server message block (SMB) protocol while a Linux or UNIX client will have a network file system (NFS) protocol. 

• Operating System: While standard operating systems can handle thousands of requests, the NAS OS restricts the system to two types of requests, data storage and file sharing. 

While NAS technology has been around for a few decades, it has recently seen a resurgence in its adoption. According to a recent IDC survey (link resides outside IBM), 44% of survey respondents run less than 40% of their apps and workloads on all-flash arrays, but this number is expected to grow due to increasing storage demands.  This need is primarily driven by the growth of unstructured data and the acceleration of business transformation and cloud migration efforts as a result of the COVID-19 pandemic. As businesses also seek to leverage emerging technologies, such as AI, machine learning, and edge computing, these workloads will need to be stored together to facilitate insights and learning. Finally, NAS systems are also commonly used to support cloud storage providers, acting as a data backup, archiving, and disaster recovery system.