Network-Attached Storage (NAS)

Your photos live on your laptop. Your documents on your desktop. Your videos on an external drive somewhere. Backups? Scattered or nonexistent. When you need something, you hunt across devices hoping to find the right version.

Network-Attached Storage solves this. A NAS is a dedicated storage device that connects to your network and becomes the single place where files live. Every computer sees it as just another folder—but the files actually reside on a centralized, protected, always-available device.

The Magic Trick

From your computer, NAS storage appears as a network drive or mounted folder. You open it, drag files in, save documents there. It feels like local storage. The magic is that five other people can do the same thing simultaneously, all seeing the same files, all changes syncing instantly.

This works through file-sharing protocols—SMB for Windows (also works on Mac and Linux), NFS for Unix/Linux systems. Your computer speaks these protocols natively. Connecting to a NAS requires no special software, just pointing your file browser at a network address.

What's Inside

A NAS device is essentially a small computer optimized for one job: serving files reliably.

Hard drives or SSDs store your data, usually configured in RAID arrays so a drive can fail without losing anything.

A specialized operating system handles file sharing, user permissions, and data protection. Synology's DSM, QNAP's QTS, and TrueNAS are examples—purpose-built for storage.

Network connections link the NAS to your network. Consumer units have gigabit Ethernet; business units often have 10-gigabit or multiple ports for redundancy.

Enough processing power to handle multiple simultaneous users, run backup jobs, and manage RAID operations.

RAID: Protection Against Hardware Failure

Most NAS devices configure drives in RAID (Redundant Array of Independent Disks). The idea: spread data across multiple drives so one can fail without catastrophe.

RAID 1 mirrors everything across two drives. If one dies, the other has a complete copy. Simple but uses half your capacity for redundancy.

RAID 5 needs three or more drives. Data is striped across all of them with parity information distributed throughout. One drive can fail; the array rebuilds from parity. Better capacity efficiency than mirroring.

RAID 6 is RAID 5 with double parity—survives two simultaneous drive failures. Requires four or more drives.

RAID 10 combines mirroring and striping. Fast and redundant, but expensive—you need at least four drives and lose half the capacity.

Here's the critical point: RAID protects against drive failure. It is not backup. If ransomware encrypts your files, RAID faithfully preserves the encrypted garbage on multiple drives. If you accidentally delete something, RAID ensures it's gone from all copies simultaneously. You still need real backups—separate from the NAS, ideally offsite.

What People Actually Use NAS For

Centralized file sharing. The marketing team stores assets in one place. Everyone accesses the same files. No more emailing attachments or wondering who has the latest version.

Media libraries. Movies, music, photos—all in one place, streamable to any device in the house. Plex, Jellyfin, and similar apps run directly on many NAS devices.

Backup destination. Instead of backing up each computer to its own external drive, everything backs up to the NAS. One location to protect, one place to restore from.

Surveillance storage. IP cameras record continuously. A NAS with enough capacity and the right software becomes a complete security system.

Personal cloud. Synology Drive, Nextcloud, and similar tools let you sync files across devices and access them remotely—like Dropbox, but you own the hardware and data.

Home vs. Business

Home NAS devices from Synology, QNAP, or Western Digital cost a few hundred dollars (plus drives). They're designed for non-experts: web-based setup, app stores for additional features, smartphone apps for remote access. A two-bay unit with a couple of 4TB drives handles most home needs.

Business NAS scales differently. More drive bays (8, 12, 24 or more). Redundant power supplies and network connections. Faster processors for more concurrent users. Enterprise features like snapshots, replication to disaster recovery sites, and integration with directory services for user management.

The underlying technology is the same. Business units just have more of everything and better support agreements.

The Network Bottleneck

NAS performance is limited by your network, not the drives inside. Gigabit Ethernet—still the most common in homes and small offices—maxes out around 125 MB/s. That's fine for documents and photos but slow for video editing or other large-file workflows.

10-gigabit Ethernet removes this bottleneck but requires compatible switches and network cards. It's increasingly common in business environments and starting to appear in high-end home setups.

SSDs in a NAS can be faster than hard drives, but if your network is the bottleneck, you won't see the benefit for normal file access. SSDs still help with random I/O and running applications directly on the NAS.

NAS vs. Cloud Storage

NAS: One-time hardware cost. Local network speeds. You control your data. Works without Internet. Add capacity by adding drives.

Cloud: No hardware to maintain. Accessible from anywhere. Built-in offsite protection. Someone else handles reliability.

The smart approach: use both. NAS for primary storage and local access. Cloud backup for offsite protection. Your files live on your NAS, but if your house floods, a copy exists in someone else's data center.

Security Matters

A NAS holds your data. Protect it accordingly.

User accounts and permissions control who sees what. Not everyone needs access to everything.

Encryption protects data if the physical device is stolen. Enable it during setup—adding encryption later usually means wiping and starting over.

Network isolation keeps the NAS on your trusted internal network. Exposing it directly to the Internet invites attacks. Remote access should go through VPN or the manufacturer's secure relay service.

Updates patch security vulnerabilities. NAS operating systems need updates just like any other software.

When NAS Isn't the Answer

NAS provides file-level storage. You access files through folders and filenames. This works for documents, media, backups—most things humans interact with directly.

Some applications need block-level storage—direct access to raw disk space. Databases, virtual machines, and other performance-sensitive workloads often perform better with SAN (Storage Area Network) or direct-attached storage. NAS can work for light virtualization and some databases, but it's not the ideal tool.

If you need multiple petabytes of storage or thousands of concurrent users, you've outgrown single-box NAS. Scale-out storage systems, object storage, or cloud solutions become necessary.

The Simple Version

NAS is a hard drive that lives on your network instead of inside your computer. Everyone can access it. Files live in one place instead of scattered everywhere. Drives can fail without losing data. It's the answer to "where should I keep my stuff?"

The complexity exists to make that simple experience reliable—RAID rebuilding, protocol translation, user management, data protection. But from your perspective as a user, it's just a folder that happens to be really well protected and available from any device.