NAS

A NAS is essentially a small, power-efficient computer dedicated entirely to storing and serving files. It connects to your router via Ethernet (never Wi-Fi for primary use) and advertises shared folders over SMB (Windows file sharing), NFS (Linux/Unix), or AFP (legacy macOS). Any device on the LAN can mount these shares and read or write files as if they were local. Consumer NAS units from Synology, QNAP, and others run full Linux-based operating systems with app stores — supporting Plex media servers, Docker containers, backup software, and more.

NAS vs DAS vs SAN

These three storage architectures are often confused. NAS (Network-Attached Storage) is a file server that speaks file-level protocols over an IP network — you access it like a shared folder. DAS (Direct-Attached Storage) is a disk enclosure connected directly to one computer via USB, Thunderbolt, or SAS — only that machine sees it; it cannot be shared over a network without extra software. SAN (Storage Area Network) is a block storage fabric — typically fibre channel or iSCSI — that presents raw block devices to servers as if they were internal drives. SANs are enterprise infrastructure costing tens of thousands of dollars; NAS is the practical choice for homes and small businesses where file-level sharing over Ethernet is sufficient.

NAS hardware components

Entry-level NAS units like the Synology DS223 use an ARM SoC (low power, quiet, capable of 4K transcoding with hardware assist). Mid-range and prosumer units like the Synology DS923+ or QNAP TS-464 use Intel Celeron or AMD Ryzen x86 processors — necessary for running virtual machines, heavy Docker workloads, or CPU-based Plex transcoding. Drive bays (2, 4, 6, or 8) determine how many disks you can install; more bays allow higher RAID levels or larger raw capacity. RAM matters for ZFS-based systems like TrueNAS, which benefit from 8–32 GB for caching. Dual NIC models allow link aggregation (bonding two 1 GbE ports for 2 Gbps effective throughput) or connection to both a management and data network.

File protocols

SMB/CIFS is the dominant protocol for Windows and modern macOS — it is what Windows uses natively for \\server\share paths. All current NAS operating systems implement SMB 2/3, with SMB 3 adding encryption and multi-channel support. NFS (Network File System) is the standard for Linux clients and VMware ESXi datastores; it is faster and lighter-weight than SMB for Unix workloads. AFP (Apple Filing Protocol) was Apple's native protocol through macOS High Sierra; it is deprecated in current macOS releases, which now prefer SMB. Modern NAS units support all three simultaneously — Windows machines connect via SMB, Linux servers via NFS, and legacy Macs via AFP if needed.

RAID on NAS

RAID is the mechanism NAS units use to spread data across multiple drives for redundancy or performance. Each level makes a different trade-off between protection, capacity, and write performance:

RAID is not a backup. It protects against a drive failing mid-use but does nothing for accidental file deletion, ransomware encryption, or a physical disaster destroying the unit. Always keep at least one copy offsite — either cloud sync or a physically separate drive.

NAS use cases

• Plex media server: A NAS with a capable SoC or x86 CPU can transcode video streams for Plex clients that need a different codec or bitrate. The 4K HDR transcoding is CPU-intensive; hardware-accelerated NAS models handle it where software-only units cannot.
• Time Machine backup: macOS Time Machine can target an SMB share on a NAS, creating automated hourly backups of every Mac on the network without an attached USB drive.
• Docker container host: Mid-range NAS units running Synology DSM or QNAP QTS support Docker, letting you run Nextcloud, Home Assistant, AdGuard Home, or self-hosted services without a separate server.
• Cloud sync: NAS platforms include clients for Backblaze B2, Amazon S3, and other object storage services — automated offsite backup runs without intervention.

Network speed requirements

Connect your NAS via Gigabit Ethernet (1 GbE) at minimum — this provides ~112 MB/s, enough for HD media playback and large transfers for one or two users. For 4K streaming to multiple simultaneous clients, or fast backup windows that need to complete overnight, 2.5 GbE (280 MB/s) or 10 GbE (1,100 MB/s) avoids the link being the bottleneck. Most spinning hard drives sustain 150–200 MB/s sequentially, so 1 GbE is already the weakest link in many setups. SSD-cached or all-SSD NAS units can genuinely saturate a 10 GbE link. Use a wired connection — never Wi-Fi as the primary NAS link.

Popular NAS brands and platforms

Synology DS-series (DS223, DS923+, DS1823xs+) run DSM (DiskStation Manager) — widely praised for its polished UI and mature ecosystem of first-party apps. QNAP TS-series (TS-464, TS-873A) run QTS and offer more hardware flexibility, including PCIe expansion slots for 10 GbE or NVMe cards. TrueNAS Scale is a free, open-source ZFS-based platform for custom builds — ideal if you want enterprise-grade data integrity and are comfortable building your own hardware. TrueNAS Scale supports Kubernetes-based apps and SMB/NFS/iSCSI simultaneously.

Owning a NAS vs cloud storage: five-year cost

A 2-bay NAS with 2x 4 TB drives costs roughly $400–600 upfront. Over five years, electricity (~10–15 W idle) adds approximately $50. Total: ~$650 for 8 TB raw / 4 TB usable (RAID 1). By contrast, 4 TB of cloud storage on Google One costs ~$100/year ($500 over five years) with no hardware to manage. The NAS wins on long-term cost for larger capacities — 16 TB usable on a NAS costs roughly the same five-year total as ~$1,200 in cloud subscriptions. Cloud storage wins for offsite redundancy and zero maintenance.

Frequently Asked Questions

What can a NAS do that an external hard drive cannot?

A NAS is always-on and network-accessible — any device connects without a host PC. It supports RAID for redundancy, simultaneous multi-user access, media streaming via Plex, remote access, Docker apps, and automated backups. External drives require a connected computer to share files.

What network speed do I need for a NAS?

1 Gbps Ethernet is the minimum for comfortable use (~112 MB/s). For multiple simultaneous users or fast backup of large files, 2.5 GbE or 10 GbE is worth the upgrade. Spinning HDDs max out around 150–200 MB/s, so 1 GbE is often the bottleneck regardless.

What is RAID in a NAS?

RAID combines drives for redundancy. RAID 1 mirrors two drives; RAID 5 stripes with parity across 3+ drives (tolerates one failure); RAID 6 tolerates two. RAID is not a backup — it does not protect against deletion, ransomware, or physical disasters. Always keep a separate offsite copy.