What Is a Network Attached Storage (NAS)?

What is a Network attached storage (NAS)?


A network-attached storage (NAS) device is a data storage device that connects to and is accessed through a network, instead of connecting directly to a computer. NAS devices contain a processor and operating system so it can run applications and provide the intelligence needed for files to be easily shared by authorized people.

The beauty of a NAS device is that it can be easily accessed by multiple people, multiple computers, mobile devices, or even remotely (if set up properly).

  • Directly to your computer.This is what most of us do at home when we need more storage than our computer or laptop holds. Most often, you’d use a USB cable to connect a hard drive or SSD to your computer’s USB port.

    Mac users might use Thunderbolt cables and ports. There are ways to share access to that hard drive with others, but usually, the hard drive is used exclusively by the computer it’s attached to. You might hear this referred to as direct-attached storage (DAS).

  • Via a network. We’re referring to your local network at your business or in your home, which might be a hard-wired ethernet network or a WiFi-enabled network.

    As mentioned above, storage devices connected to networks are called network-attached storage, or NAS, devices. NAS devices are configured for access via permissions to users on an internal network, though you can usually set up access to your NAS devices via the internet, should you choose to do so.

    While Cloud storage in the Wide Area Network (WAN) could be argued as the third method to connect computers and information as highlighted below, for sake of this discussion, we’ll confine ourselves to a local network other than this brief note.

  • Cloud storage. Azure, Amazon Web Services, iCloud, and many others are forms of network-attached storage, but for sake of discussion, we’ll confine ourselves to a local network.

    Most people opt for attaching storage to their own networks when they care about keeping costs fixed or predictable, if they want the ability to access their data and files during internet outages, or if they’re concerned about privacy and data security.

How a NAS device works


Your computer will read data from and write (store data) to DAS devices faster than network devices. Depending on the size of your files and what you’re trying to do, you may notice a difference.

Editing large photos or videos, working with complex design documents, or transferring very large files are examples when using DAS is generally advantageous.

While NAS read/write performance isn’t as fast as DAS external storage, NAS devices are more sophisticated than DAS.

To support the variety of ways people want to use network-attached storage, NAS devices have several components integrated into their architectures:

  • Storage. Usually, with hard disk drives, the primary function of a NAS device is to store your files. The most popular NAS devices for home office, small business, or enterprise workgroup contain two to five hard drives. While multiple hard drives clearly provide more capacity than a single hard drive, they can also provide redundancy and faster file access and storage times. NAS devices typically use a special NAS category of 3.5-inch hard drives that stand up to the requirements of a device that is constantly running.

  • Networking. This is how the NAS device is connected to your computer(s). The network attachment can be via ethernet cable (hardwired) or Wi-Fi. While many NAS devices contain USB ports, these ports are not used to connect the NAS device to your computer—these USB ports are for connecting other devices to your NAS device, whether for charging, for backing up the NAS device, or for otherwise transferring data.

  • Computer**/**CPU. NAS devices contain a CPU of some kind since it takes computing intelligence and power to manage the filesystem, read and write operations, run applications, process multimedia files (such as video), manage multiple users, and integrate with the cloud if desired.

  • Operating System. While it may not seem to the average user that there’s an operating system that manages the storage device, NAS devices have to have an OS on them to take care of the tasks that would otherwise be managed by a computer for DAS devices. The operating system is also needed to run the wide variety of applications available on NAS devices:

  • Business applications, such as CRM and ERP

  • Multimedia transcoding and serving

  • Productivity tools such as email, documents, spreadsheets, etc.

  • Collaboration and file-sharing applications

  • Private/public cloud integration

  • Web servers

  • Software development


  • seagate.com/fr/fr/tech-insights/what-is-nas-master-ti/

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