Network attached storage (NAS) is a dedicated storage device connected to a network that provides shared file access to multiple users and devices. A NAS holds one or more hard drives, runs a lightweight operating system, and connects to the network through Ethernet, so any authorized device reaches its files over standard sharing protocols. Synology and QNAP are the two most recognized NAS manufacturers.
This article defines network attached storage, explains how a NAS works, lists its common uses, describes RAID for redundancy, compares a NAS with an external drive and with cloud storage, and identifies the main NAS brands. A comparison table sets NAS against direct-attached storage and cloud storage.
Each section states one part of the topic and connects it to the shared, network-connected storage at the center of the definition. The result is a complete account of what network attached storage is, how a NAS provides file access, and when a NAS suits a home or office better than other storage options.
What Is Network Attached Storage (NAS)?
Network attached storage (NAS) is a dedicated storage device connected to a network that provides shared file-level access to multiple users and devices. A NAS combines drives, a processor, and a storage operating system in one unit that attaches to the network through Ethernet, so files become available to every authorized device. The defining traits of network attached storage are listed below:
- A dedicated device serves storage as its only function, separate from any single computer.
- A network connection through Ethernet makes the storage reachable to many devices at once.
- File-level access shares folders and files over protocols such as SMB and NFS.
- Multiple drive bays hold several hard drives that combine into one shared storage pool.
A NAS connects to the local network and receives an address, often assigned by the DHCP server on the router. Combining several drives into one protected volume depends on the redundancy methods in the guide to RAID levels.
How Does a NAS Work?
A NAS works by running a storage operating system that manages its drives and shares files over the network using protocols such as SMB and NFS. A NAS receives file requests over Ethernet, reads or writes the data on its drives, and returns the result to the requesting device. The way a NAS works is described below:
- Hard drives in the NAS bays store the data and combine into one or more volumes.
- A storage operating system manages the drives, user accounts, and file permissions.
- An Ethernet connection links the NAS to the network so devices reach the shared files.
- File-sharing protocols such as SMB for Windows and NFS for Linux deliver file-level access.
A NAS uses file-level protocols, so devices request whole files and folders rather than raw disk blocks, which distinguishes a NAS from block-level storage. The NAS communicates over the transport and addressing layers explained in the overview of TCP/IP, the same suite that carries all network traffic.
What Are the Uses of a NAS?
A NAS serves four main uses: centralized file sharing, automated backups, media streaming, and surveillance recording. A NAS gives a home or office one shared storage point that many devices reach, replacing scattered drives and manual transfers. The common uses of a NAS are listed below:
- File sharing gives multiple users one shared location for documents, photos, and projects.
- Backups collect copies from computers and phones on a schedule for recovery after data loss.
- Media streaming serves video, music, and photos to televisions, phones, and computers.
- Surveillance recording stores footage from IP cameras continuously on the network drive.
A NAS centralizes data that would otherwise spread across separate computers, so a single backup and update routine covers the whole household or office. The media and backup roles depend on the drive capacity inside the NAS, which determines how much footage, video, and archive data the device holds.
How Does RAID Provide Redundancy in a NAS?
RAID provides redundancy in a NAS by combining multiple drives so the array survives a drive failure without losing data. A RAID configuration spreads or mirrors data across drives, so one failed drive does not end access to the stored files. The RAID levels common in a NAS are listed below:
- RAID 1 mirrors data across two drives, so either drive holds a complete copy.
- RAID 5 spreads data and parity across three or more drives, surviving one drive failure.
- RAID 6 adds a second parity block, surviving two simultaneous drive failures.
- RAID 10 combines mirroring and striping across four or more drives for speed and redundancy.
RAID protects against drive failure but does not replace a backup, since RAID does not guard against file deletion, theft, or site damage. The trade-offs between capacity, speed, and fault tolerance for each level appear in the guide to RAID levels.
How Does a NAS Differ From an External Drive?
A NAS connects to the network and serves many devices at once, while an external drive connects to one computer through USB and serves only that computer. A NAS works independently of any single machine, whereas an external drive depends on the computer it plugs into. The differences between a NAS and an external drive are listed below:
- A NAS connects to the network and serves every authorized device at once.
- An external drive connects to one computer through USB and serves only that machine.
- A NAS runs continuously and supports scheduled backups and remote access.
- An external drive costs less and offers simple single-computer storage without a network.
An external drive that plugs into one computer through USB suits single-machine storage, as the guide to adding storage to a PC describes. A NAS suits households and offices that need shared access from many devices at the same time, which a single external drive cannot provide.
How Does a NAS Compare to Cloud Storage?
A NAS keeps data on a device the owner controls on the local network, while cloud storage keeps data on a provider’s remote servers reached over the internet. A NAS gives local speed and one-time hardware cost, whereas cloud storage gives offsite access for a recurring subscription. The differences between a NAS and cloud storage are listed below:
- A NAS stores data locally on hardware the owner controls, with no recurring storage fee.
- Cloud storage stores data on remote servers, reached anywhere with an internet connection.
- A NAS delivers local network speed, limited only by the drives and the local link.
- Cloud storage handles offsite redundancy and hardware maintenance through the provider.
A NAS and cloud storage often work together, since a NAS can back up its data to a cloud service for offsite protection. The way remote services connect storage and applications across the internet appears in the overview of cloud networking, which complements the local storage a NAS provides.
Which Brands Make NAS Devices?
Synology and QNAP are the two leading NAS manufacturers, with Western Digital, Asustor, and TerraMaster also producing network storage devices. A NAS brand supplies both the hardware and the storage operating system, which shapes the features and management of the device. The main NAS brands are listed below:
- Synology produces NAS units running its DiskStation Manager operating system.
- QNAP produces NAS units running its QTS operating system with virtualization features.
- Western Digital produces the My Cloud line of network storage for home users.
- Asustor and TerraMaster produce NAS units across home and small-office price ranges.
Synology and QNAP supply the operating systems that manage drives, users, and apps, which sets them apart in features for backups, media, and surveillance. A NAS buyer matches the number of drive bays and the processor to the intended use, since media streaming and surveillance demand more processing than basic file sharing.
NAS vs DAS vs Cloud Comparison Table
| Attribute | NAS | External Drive (DAS) | Cloud Storage |
|---|---|---|---|
| Connection | Network (Ethernet) | Direct (USB) | Internet |
| Access | Many devices at once | One computer | Anywhere online |
| Cost model | One-time hardware | One-time hardware | Recurring subscription |
| Speed | Local network speed | Local USB speed | Internet speed |
| Redundancy | RAID across drives | Single drive | Provider-managed |
| Best use | Shared home or office storage | Single-PC storage | Offsite access and backup |
How Do You Choose a NAS?
A NAS is chosen by matching the number of drive bays, the processor, the memory, and the network speed to the intended workload and capacity. A NAS specification determines how many drives the unit holds and how much processing it brings, which sets the storage size and the tasks the device handles. The factors that guide a NAS choice are listed below:
- Drive bays set the maximum capacity and the RAID levels the NAS supports, from two to many bays.
- The processor and memory determine whether the NAS handles media transcoding and many users.
- The network ports set the throughput, with gigabit Ethernet standard and multi-gigabit on higher models.
- The drive type matches NAS-rated hard drives for capacity or solid-state drives for speed.
A NAS for file sharing and backups runs well on a two-bay unit with a basic processor, while media streaming and surveillance need more bays and processing power. The NAS receives its network address from the DHCP server on the router, and its drives combine under the redundancy levels in the guide to RAID levels.
Key Takeaways
- Network attached storage (NAS) is a dedicated device that shares files over a network.
- A NAS works by running a storage operating system that shares files over SMB and NFS.
- Common uses include file sharing, backups, media streaming, and surveillance recording.
- RAID combines drives so a NAS survives a drive failure, but RAID is not a backup.
- A NAS serves many devices, while an external drive serves only one computer.
- Synology and QNAP are the two leading NAS manufacturers.
What is NAS in simple terms?
NAS, or network attached storage, is a dedicated storage device connected to a network that provides shared file access to multiple users and devices. A NAS holds drives and shares files over Ethernet.
How does a NAS work?
A NAS runs a storage operating system that manages its drives and shares files over the network using protocols such as SMB and NFS. Devices request files over Ethernet, and the NAS reads or writes them.
What is a NAS used for?
A NAS serves four main uses: centralized file sharing, automated backups, media streaming to devices, and surveillance recording from IP cameras. It gives a home or office one shared storage point.
Is a NAS better than cloud storage?
A NAS stores data locally with no recurring fee and local network speed, while cloud storage offers offsite access for a subscription. Many setups use a NAS and back it up to the cloud together.
Does a NAS need RAID?
A NAS does not require RAID, but RAID combines drives so the array survives a drive failure. RAID protects against hardware failure, yet it does not replace a backup against deletion or theft.
Which brands make NAS devices?
Synology and QNAP are the two leading NAS manufacturers. Western Digital, Asustor, and TerraMaster also produce NAS devices, each supplying its own storage operating system and management software.
Last Thoughts on Network Attached Storage
Network attached storage is a dedicated device connected to a network that provides shared file-level access to multiple users and devices. A NAS runs a storage operating system, shares files over SMB and NFS, and serves file sharing, backups, media streaming, and surveillance from one central point. RAID combines drives so the array survives a drive failure, a NAS serves many devices where an external drive serves one, and a NAS stores data locally where cloud storage keeps it offsite.
Synology and QNAP lead the market. Readers can continue with the guide to RAID levels, the guide to adding storage to a PC, the overview of cloud networking, or the guide to how networks work.
