Who's this for?
Left to right: QNAP TS-251, Synology DiskStation DS214, Western Digital MyCloud Mirror, Asustor AS-5002T, Synology BeyondCloud Mirror.
A NAS device is a small computer with an Internet connection, at least one hard drive bay, an operating system that's optimized for network storage. It's the best way to add terabytes of storage space to every computing device you own.
A NAS is great for people with large collections of movies, photos, and music: you can store all your media in one place and stream them to computers, speakers, phones and tablets, and your home theatre system. You can also use your NAS to backup your computers, or it can act as your own personal "cloud storage" with remote access and smartphone apps.
Most NAS can even act as email, database or VPN servers; BitTorrent boxes; website hosts; or as DVRs for surveillance cameras, while using about the same amount of energy as a couple of LED bulbs.
How we decided
We tested read and write performance by copying a 1.48GB file between each NAS and a Dell Latitude 3550 laptop, each connected to the same router via Ethernet.
Our ideal NAS has two hard drive bays. Dual-drive NAS devices support drive mirroring—the contents of one drive are copied to the other, so your data is safe even if a hard drive fails. It should also support hot-swapping—changing hard drives without turning off the NAS. It should have several USB ports, for backing up external drives to the NAS (and vice versa) as well as connecting printers or Wi-Fi dongles. Setup should be simple, and it should come with good mobile apps for media streaming and remote access.
We focused on NASes that cost less than $350 (diskless). Cheaper NASes have underpowered hardware, only one drive bay or operating systems that are complicated or half-baked. More expensive NAS are overkill for most home use.
The QNAP TS-251 is fast, powerful, and energy-efficient.
The QNAP TS-251 ($319 without hard drives) is fast: it can read and write data over the network at more than 100MB per second. Drive mirroring and hot swap work well, it's easy to setup and use, and it supports a plethora of third-party apps, like Plex and Wordpress. Its operating system, QTS, is novice-friendly but has enough power and detailed configurations for power users.
The TS-251 has a dual-core Intel Celeron processor and 1GB or 4GB of RAM (expandable up to 8GB). It has two USB 2.0 ports and two USB 3.0 ports, and is one of the few NAS we tested that has an HDMI port, so you can connect it to your home theater system and play movies and media directly to your TV.
We don't like that the TS-251's chassis and drive bays are a little cheap-feeling and flimsy; it's not quite powerful enough for reliable on-the-fly video transcoding through Plex Media Server, the most popular media-streaming app.
You can buy a TS-251 with hard drives included, but it's usually cheaper to buy drives separately. We like Western Digital Red drives, which are designed for home NAS use. Two 4TB drives will give you 4TB of total storage (because the drives are mirrored) and will cost around $320 on top of the cost of the NAS.
The Synology DS214 without its front cover. Its drive trays are more solid than the QNAP's, but this NAS has a less powerful CPU and no HDMI port.
If the TS-251 is unavailable, or too expensive, we recommend the $290 Synology DS214. It's almost as fast as our pick, though it has less RAM and a less powerful CPU. The DS214 lacks expandable memory and doesn't have an HDMI port. Synology's operating system is very similar to QNAP's and has essentially the same features, but QNAP has a bit better value for the price.
The basic, budget-friendly NAS
The Western Digital My Cloud Mirror could be called "a NAS for those who have never used a NAS."
If you don't need all the advanced features of a QNAP or Synology NAS, or want to save a few bucks, we recommend the Western Digital My Cloud Mirror. It does all the basic NAS stuff; it just lacks the more esoteric features like an email or web server, and surveillance cam video recording. It's also somewhat easier to use, and cheaper than either of our main picks: a My Cloud Mirror with two 2TB drives is $285; one with two 4TB drives is $440.
The QNAP TS-251 is the best home NAS for most people who need one. It's fast, it has powerful hardware and software, and you can connect it directly to your TV or media center via HDMI for fast media playback. Unlike most NAS, you can add RAM later so it'll stay speedy for years.
This guide may have been updated by The Wirecutter. To see the current recommendation, please go here.