What is NAS storage and how it works?

Network-attached storage, or NAS, is a storage device that is connected directly to a network, rather than to a single computer. NAS provides centralized data storage and retrieval for multiple users and devices on a network. Some key features of NAS include:

What is NAS?

NAS, or network-attached storage, is a dedicated file storage device that enables multiple users on a local area network (LAN) to store and retrieve data from a centralized location. Simply put, a NAS device is a computer that is dedicated solely to file sharing. NAS systems contain one or more hard drives that are arranged in a RAID (redundant array of independent disks) configuration for protection against drive failure. NAS devices connect directly to a network, rather than to a specific computer. They enable authorized network users to access and share files in a central location.

NAS systems are appliances made for file sharing that do not provide any other computing functions. They run an operating system specifically optimized for file sharing, and they do not run other applications that would tax the system’s resources and reduce performance. This distinguishes NAS devices from general purpose file servers, which perform other computing functions besides file storage and sharing.

With dedicated hardware and software, NAS devices are engineered to provide fast file access and sharing capabilities for home and business users. NAS enables multiple computers, tablets, smartphones and other devices on a network to access files and storage capacity on a central, shared storage system. Users can access files on the NAS just like on a local drive. NAS systems also streamline storage management and backup tasks for IT administrators.

Benefits of NAS

NAS offers several benefits that make it a popular choice for file sharing and data storage in homes and organizations:

  • Centralized storage – Rather than saving files to individual devices, NAS enables central storage of files in one place. This makes it easy to organize and access data.
  • Shared storage – NAS allows multiple users and devices to access the same files simultaneously.
  • Flexibility – NAS can be accessed on the local network and remotely via the internet depending on the configuration.
  • Scalability – Additional NAS storage capacity can easily be added as needs grow by expanding the RAID array.
  • Continuous access – NAS continues to operate and provide file access even if an individual computer is powered off.
  • Backups – Automated backup of computers and other devices to the NAS protects against data loss.
  • RAID protection – The RAID array on most NAS devices provides protection against drive failure and continuous access to data.

These capabilities make NAS ideal for supporting multiple computers and users that need to store, backup, protect, and share files on a home or office network.

How NAS Works

NAS devices contain the operating system and storage management software, as well as the hard disk drives for storage capacity. This enables them to function independently, without the need for a separate computer to control the storage. Here are the key components of a NAS system:

  • Operating system – This specialized OS manages the file sharing and storage. Many NAS devices run a Linux-based OS optimized for storage.
  • Network interface – This allows the NAS to connect to the local network via Ethernet, WiFi, or both.
  • Processor – The CPU carries out the storage management and sharing tasks. Low-power processors allow quiet, cool operation.
  • RAM – Memory supports the processes running on the NAS. More RAM provides better performance.
  • Storage drives – Hard disk drives provide the data storage capacity. NAS supports multiple drives and RAID configurations.

With these built-in computing components, NAS can operate independently to serve files over the network. When a user on the network wants to access files, the NAS operating system handles authenticating the user and retrieving the requested files from the storage drives to transfer over the network connection.

Common NAS Features and Protocols

In addition to the basic functionality of centralized file storage and sharing, NAS devices also provide many convenience and security features for users. Some commonly supported NAS capabilities include:

  • Automated backups – Back up files from networked devices to the NAS on a schedule.
  • Remote access – Access files over the internet when away from the local network.
  • Link aggregation – Combine Ethernet ports for faster data transfers.
  • Cloud support – Sync or backup NAS data to cloud storage services.
  • Data encryption – Encrypt data on the NAS to prevent unauthorized access.
  • Snapshot replication – Make point-in-time copies of data for backup purposes.
  • Virtual drives – Create separate storage volumes with or without RAID.

NAS devices support standard network file sharing protocols that enable seamless integration and access on a network. The main protocols include:

  • SMB/CIFS – Allows NAS access from Windows PCs and devices.
  • AFP – Used for NAS access from Mac computers.
  • NFS – For NAS access from Linux/UNIX systems.
  • FTP – Enables file transfers between NAS and remote systems.
  • HTTP/HTTPS – For NAS administration and configuration via web apps.

Types of NAS Systems

There are several categories of NAS systems tailored for different use cases:


Small office and home office (SOHO) NAS devices have 1-4 drive bays and lower computing power suited for basic home and small business file sharing needs. They typically support key protocols like SMB, AFP, FTP. Capacities from 2 TB to 60 TB+ are available for home and SOHO NAS devices.

Rackmount NAS

Rackmount NAS systems can pack 10 or more high capacity hard drives in a chassis designed to install in a standard data center equipment rack. Expandable and redundant, rackmount systems offer enterprise-grade performance and availability for business-critical data. Capacities scale from tens of terabytes up to petabytes.

All-Flash NAS

All-flash NAS replaces hard disk drives entirely with high performance solid state drives. Extremely fast access makes all-flash NAS ideal for applications needing ultra-low latency like video editing. However, the cost per terabyte remains high for all-flash storage.

NAS Type Typical Drive Bays RAM Suited For
Home/SOHO NAS 1-4 1-4 GB Personal and small business file sharing
Rackmount NAS 10-100+ 32-512 GB Enterprise networks and data centers
All-Flash NAS 10-24 64-512 GB Demanding applications needing ultra-low latency

Scale-Out NAS

Also known as clustered NAS, scale-out systems interconnect multiple NAS devices to create a unified storage pool. This allows performance and capacity to easily scale by adding more nodes. Dynamic data movement optimizes resources across the cluster. Scale-out NAS can grow to multi-petabyte capacity.

NAS vs. Direct-Attached Storage

Direct-attached storage refers to internal hard drives installed inside a computer, or external USB drives plugged directly into one computer. The main differences between DAS and NAS include:

Direct-Attached Storage Network-Attached Storage
Internal or external disk connected to a computer Standalone appliance connected to a network
Data only accessible by the connected computer Data accessible by multiple computers on the network
Managed by the computer’s operating system A dedicated OS manages the NAS
Limited to storage capacity of the computer Scalable capacity by adding NAS drives
Data isolated and difficult to share Centralized data easy to access and share

The limited capacity and accessibility of DAS makes it best suited for individual users. For centralized, shareable data storage, NAS is a superior choice.


Storage area networks (SANs) also provide shared storage resources for multiple computers. But whereas NAS devices connect directly to the local area network, SANs operate on a dedicated storage network. This key difference leads to several other distinctions:

Network-Attached Storage Storage Area Network
Shares files over Ethernet LAN Shares data blocks over Fibre Channel SAN
Each device is identified by IP address Devices access SAN using WWPN identifiers
Better suited for file services like shared folders Ideal for block-based storage like databases
File-level access, storage management Block-level access, makes storage appear local
Lower cost, complexity Provides high performance, availability

NAS solutions excel at general file storage and sharing. SANs are designed to support real-time critical applications, databases, email servers and virtualized workloads at scale. Many organizations deploy both technologies to obtain centralized storage for diverse uses.

Setting Up a NAS

Setting up a NAS device involves three main steps:

  1. Connect the NAS to the network – Use Ethernet cables to connect the NAS network ports to routers, switches, or hubs on the LAN.
  2. Configure the NAS – Run the setup wizard, create storage volumes, enable services like FTP, servers, etc. Most NAS devices provide a web interface for configuration.
  3. Map NAS shares to users – Create user accounts and set permissions on folders. Map shared folders as network drives for seamless access.

That’s it! Once the shares are defined, users can access files on the NAS similarly to a regular folder on their computer. Administrative tasks include occasional software updates, user management, and storage capacity expansion as needed.

Major NAS Vendors and Options

Many companies offer NAS solutions to fit a variety of needs and budgets. Here are some of the major vendors and product lines:

  • QNAP – Offers NAS for home and business with capacities up to 1,000 TB. Options include Turbo NAS, TVS-x80, TS-x77XU, and scale-out QuTS hero series.
  • Synology – DiskStation and RackStation NAS with up to 60 bays for SOHO, enterprise networks. Runs Disk OS.
  • Asustor – Home and office NAS like Lockerstor with ADM OS. High-end options like AS6510T for larger networks.
  • WD – My Cloud and My Cloud Pro consumer and small business NAS devices. Models available up to 32 TB.
  • Netgear – ReadyNAS line includes desktop and rackmount. Runs ReadyNAS OS.
  • Drobo – Simplified NAS devices for SMB and home users. B800fs and B810n flagship models.

NAS options are also available from Dell, HPE, Lenovo, Buffalo, Seagate, Open-E, Zyxel, Thecus, TerraMaster and more. Both ready-made appliances and DIY servers built on standard hardware are options.

Best Practices for NAS Deployment

Follow these guidelines when architecting and managing a NAS environment for optimal performance, protection and return on investment:

  • Choose NAS capabilities that match your workload needs and growth requirements.
  • Allocate 1.5x estimated storage capacity for room to grow.
  • Use RAID 6, RAID 10 or erasure coding for redundancy against drive failure.
  • Configure automated backups from computers to NAS storage.
  • Place NAS on a UPS to avoid data corruption during power failures.
  • Isolate NAS traffic on a separate virtual LAN if possible.
  • Manage user access with permissions, quotas to avoid monopolizing capacity.
  • Monitor NAS performance – CPU usage, network throughput, disk utilization.

Taking the time to architect your NAS deployment for reliability, security and scalability will maximize the value you achieve.

The Future of NAS

NAS technology will continue evolving to power next-generation data infrastructures. Emerging trends in NAS capabilities include:

  • Higher speed networks – 25GbE, 40GbE, 100GbE support allows NAS to leverage high bandwidth networks.
  • NVMe-oF support – Enables flash SSD arrays to connect over Ethernet and Fibre Channel.
  • AI integration – Assists with predictive storage management, anomaly detection, cybersecurity.
  • Hybrid cloud support – Seamlessly manage and migrate data between NAS and public cloud storage.
  • Erasure coding – More storage efficient alternative to RAID for large-scale NAS environments.

By incorporating cutting edge technologies like NVMe flash, AI, and multi-gigabit networking, NAS continues to evolve as a versatile networked storage platform for the hybrid cloud era.


NAS enables organizations to achieve the benefits of high capacity consolidated storage combined with ease of sharing across networks. With capabilities that span from compact home NAS devices up to enterprise SAN alternatives, the technology provides flexible solutions for any use case that benefits from centralized, shared files. Purpose-built NAS operating systems and hardware tightly integrate storage resources and networking connectivity to deliver efficient, scalable networked data storage for the modern business.