What is network-attached storage?

Network-attached storage (NAS) is a file-dedicated storage device that makes data continuously available for employees to collaborate effectively over a network. Any computer network has interconnected server machines and client machines that send requests to the servers. NAS devices are specialized servers that handle only data storage and file-sharing requests. They provide fast, secure, and reliable storage services to private networks.

Why are NAS devices important?

Enterprise and small businesses in many industries choose NAS solutions because they offer effective, scalable, and low-cost storage. Compared to other servers, NAS file servers give faster data access and are easier to configure and manage. They can support various business applications, including private email systems, accounting databases, payroll, video recording and editing, data logging, and business analytics.

Some benefits of NAS include:

On-premises data centers for organizations

An on-premises data center uses cloud computing resources from an organization's own datacenter. It could be owned or leased but is controlled wholly by the organization and not a third-party. An on-premises data center is sometimes called a "private cloud." You can use NAS appliances to deploy an on-premises data center for private cloud storage in your organization.

Flexible local storage solutions for small businesses

NAS systems can be customized based on the size and requirements of the organization.

What is network-attached storage used for?

Organizations use NAS solutions to perform a number of tasks including:

  • File storage and sharing
  • Create active data archives or for data backup and disaster recovery
  • Host virtual desktop infrastructure
  • Test and develop web-based and server-side web applications
  • Stream media files and torrents
  • Store images and videos that require frequent access
  • Create an internal printing repository

For example, a media company creates many images every day. However, the company cannot stream this data to the cloud constantly because of network latency. Instead, it uses a high-end NAS device to store the photos. Any employee can access and edit these photos over the company network.

What are the components of a NAS device?

NAS devices are typically made up of several components like:

Physical storage drives

NAS devices can contain from two to five hard drives, which gives them high-volume storage capacity. Multiple physical drives are arranged logically as redundant storage containers (RAID). RAID is a virtualization technology that combines multiple physical storage components into one or more logical units. This helps back up data and improve performance.

Central processing unit (CPU)

NAS devices have a CPU that provides computing intelligence and power to manage the file system. The CPU reads and writes data to process and serve files, manage multiple users, and integrate with the cloud if desired.

Operating system

An operating system is a software interface between the storage device hardware and its user. Although complex network-attached storage devices come with their own operating systems, some simpler devices may not have one.

Networking interface

The NAS unit connects to the network by using the networking interface. The network connection can be an ethernet cable or Wi-Fi. Many NAS devices also have USB ports for charging or to connect other devices to the NAS device.

What is the basic storage principle of NAS devices?

NAS is a file storage system. There are three main storage methodologies:

File storage

In cloud file storage, you can store data in files, organize files into folders, and place them under a hierarchy of directories and subdirectories. It is a popular and familiar storage technique.

Block storage

Block storage breaks a file into smaller chunks (or blocks) and stores each block separately under a unique address. The computer can store blocks anywhere on the device. The server's operating system uses the unique address to reassemble the blocks into the file. This is faster than looking through hierarchies to access a file.

Object storage

Objects are discrete units of data that are stored without a hierarchy or structure. Each object includes the data, descriptive information about the data (metadata), and a unique identifying number. Using this information, system software can find and access the object.

File vs. block vs. object storage

Each storage type can be used in different ways. For example, file storage for local file sharing, or database and business applications, and block storage for high-performance applications. On the other hand, you can use object storage to store unstructured data like email, videos, image files, web pages, and sensor data produced by the Internet of Things (IoT).

How does NAS work?

NAS systems combine hardware and software with protocols (or rules) to support file sharing over the network. By following these protocols, any computer can seamlessly access files from the NAS device as if the files were stored on the computer itself.

Communication protocols

Networks can run multiple data transfer protocols, but most networks have internet protocol (IP) and transmission control protocol (TCP). IP is the part that obtains the address to send file data. After that, TCP delivers the data by combining it into packets and sending the packets through the network.

File formatting protocols

Machines in a computer network can have different underlying operating systems, like Windows, Linux, or Unix. All of them want to access the NAS file storage in their native file format. Therefore, NAS file systems format the data before sending it to the network. The formatting protocols for file serving include:

Network file systems (NFS)

Linux and UNIX systems use this protocol. NFS works on any hardware, OS, or network architecture.

Server message blocks (SMB)

Microsoft Windows machines use this protocol.

Apple filing protocol (AFP)

This is a proprietary protocol for Apple devices running macOS.

What are the different types of NAS devices?

NAS vendors manufacture NAS as:

Computer-based NAS

Some NAS devices are purpose-built computers with processors and operating systems. Although it may technically be possible to run other software on a NAS unit, a computer-based NAS is not designed to be a general-purpose server. For example, NAS units usually do not have a keyboard or display and are controlled and configured over the network.

Embedded system NAS

A full-featured operating system is not needed on a NAS device, so some NAS vendors embed a lightweight operating system directly in the hardware.

Integrated chip-based NAS

The lowest level NAS device uses an integrated microchip processor. It manages file server functions directly in the chip, with no operating system. These NAS devices are less common.

How does NAS compare to other storage network architectures?

NAS is one of the three main storage architectures. The other two are storage area networks (SAN) and direct-attached storage (DAS):

Storage area networks

A storage area network (SAN) provides block storage to networked devices. Each block is formatted with different protocols. For example, one block can be formatted for NFS, and another can be formatted for AFP.


The main difference between NAS and SAN is the way client machines view the storage device. To clients, NAS works as a file system and SAN works as the operating system. NAS handles individual file requests, but SAN manages requests for contiguous blocks of data. NAS and SAN also use different underlying protocols and technologies.

SAN is more flexible for users, but it can cost more to set up and manage.

Direct-attached storage

Direct-attached storage (DAS) is storage that can be directly attached to a single computer. The most common example of DAS is a cable-connected external hard drive. For another computer to access files on that drive, the cable must be removed from the original computer and attached to the new one.


DAS was the precursor to NAS. DAS performs better than NAS, especially for software programs that require more computing. However, being directly attached, it does not lend itself well to sharing and is complex to manage.

What are the limitations of NAS?

NAS is limited by its inability to deliver performance at scale.

Difficult to scale

Network-attached storage relies on hard disk drives (HDDs) to serve data. Unfortunately, if too many users send file requests at the same time, it can overwhelm the NAS system.

No service guarantees

NAS can’t offer any storage service guarantees. Users could have problems like data lag, missing data, and lost data. NAS is not reliable enough to use for mission-critical operations.

How can users overcome NAS limitations?

You can overcome NAS limitations by adding more NAS devices to the network, integrating with SAN, or replacing NAS devices with cloud storage. Let's explore the options below:

Add more NAS devices

To increase storage capacity, you can either scale up or scale out NAS architecture. Scaling up means using storage controller software to manage multiple physical drives on the same NAS server. Scaling out means using a common software communication interface called API to manage multiple NAS servers. By scaling out, organizations can make space for billions of files. However, it is costly to configure, code, and manage.

Unified storage

Despite their differences, SAN and NAS are not mutually exclusive. You can combine them to form a SAN-NAS hybrid, which gives you both file-level and block-level protocols from the same system. You can also run NAS on top of a SAN system to get filesystem services. You can find devices with hybrid SAN/NAS components in the market.

Cloud storage

You can augment or replace physical NAS by using cloud-based file storage. A cloud gateway at the edge of a company's data center network moves application data between local storage and the public cloud. A cloud provider manages and operates the data storage as a service.

Benefits of cloud storage

You can access storage on demand with just-in-time capacity and costs, eliminating the need to buy and manage your own data storage infrastructure. Cloud storage gives you agility, global scale, and durability with any time, anywhere data access.

How can AWS help with storage solutions?

Get access to free Cloud Storage by opening an AWS Account today!

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