In this age of high-resolution smartphone pictures and near-constant video shooting, the storage space in your PCs and mobile devices fills up in a flash. Need a place for it all? Consider a good network-attached storage (NAS) device. It connects to your home or office network so that you (and other users you designate) can access your files from mobile devices and PCs. We've tested the top options in PC Labs, evaluating them for everything from file transfer speeds to the apps available for NAS customization. Our top picks for most people are the Synology BeeStation (for a single-drive solution with a prepopulated hard drive) and the QNAP TS-233 (for a two-bay enclosure). Check out all of our NAS recommendations and learn more about how to find the best model in our detailed buying guide below.
Overview
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![Synology BeeStation]()
Best Single-Drive NAS Device for Most PeopleSynology BeeStation
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![QNAP TS-233]()
Best Two-Bay NAS Device for Most PeopleQNAP TS-233
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![Asustor Drivestor 2 Gen2 AS1202T]()
Best Budget NAS DeviceAsustor Drivestor 2 Gen2 AS1202T
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![Asustor Lockerstor 2 Gen2+ (AS6702T v2)]()
Best Two-Bay NAS Device for Power UsersAsustor Lockerstor 2 Gen2+ (AS6702T v2)
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![Asustor Lockerstor 4 Gen 3 (AS6804T)]()
Best Four-Bay NAS Device for Power UsersAsustor Lockerstor 4 Gen 3 (AS6804T)
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![Synology DiskStation DS1525+]()
Best Five-Bay NAS Device for Power UsersSynology DiskStation DS1525+
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![LatticeWork Amber X]()
Best Single-SSD NAS DeviceLatticeWork Amber X
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![TerraMaster F8 SSD Plus]()
Best Multi-SSD NAS DeviceTerraMaster F8 SSD Plus
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![Zettlab D4 AI NAS]()
Best AI-Augmented NAS DeviceZettlab D4 AI NAS
You Can Trust Our Reviews
Deeper Dive: Our Top Tested Picks
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![Synology BeeStation]()
Best Single-Drive NAS Device for Most PeopleSynology BeeStation
Pros & Cons
Why We Picked It
Designed for use as a personal cloud storage device, Synology’s BeeStation makes it easy to access your photos, videos, and other personal files from anywhere. Unlike other Synology network-attached storage (NAS) devices, the BeeStation does not offer RAID protection, nor does it have an app library to complement it. Instead, it makes it easy to automatically back up your data and share it with other users without paying monthly cloud subscription fees. Unlike most other NAS devices, which require you to buy your own hard drives or SSDs, the BeeStation comes prepopulated with storage.
Who It's For
People who don't want to pay subscription fees: This is a good option for those who want to stop paying for a cloud subscription to access their personal data.
Newbies: The BeeStation's strengths for people new to NAS devices are its simplicity and value. If those are not your priorities, consider spending just a few dollars more to get true NAS functionality—including RAID protection, multi-gig LAN, and a catalog of apps.
Specs & Configurations
Connection Type 1GbE Connection Type USB 3.2 Connection Type USB-C External USB Hard Disk Expansion Hard Disk Configuration Fixed Single Network Medium Wired Number of Bays 1 Rack-mount or Standalone Standalone RAID Level None Remote Access UPnP Capable Wired Network Speed 10/100/1000 Learn More Synology BeeStation Review -
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![QNAP TS-233]()
Best Two-Bay NAS Device for Most PeopleQNAP TS-233
Pros & Cons
Why We Picked It
The TS-233 packs some nice features into its stylish white enclosure, including two hot-swappable drive bays, a quad-core CPU, and a pair of USB ports for connecting external drives. Installation is easy, and the NAS turned in respectable file transfer scores during testing. Moreover, it offers a nice selection of QNAP-branded and third-party apps that turn the TS-233 into a multifunction server.
Who It's For
Style-conscious home users: Most NAS drives are black, so the TS-233's white enclosure is a welcome change, and might be ideal for people whose design tastes run on the bright side.
People who want control and customization: You can download apps from the QNAP App Store, which has dozens of QNAP and third-party apps that let you use the NAS as a multimedia server, a surveillance station for security cameras, a backup server, and more.
Specs & Configurations
Bay Size 2.5 and 3.5-inch Connection Type Ethernet Connection Type USB 2.0 Connection Type USB 3.0 External USB Hard Disk Expansion Hard Disk Configuration RAID Media Server Network Medium Wired Number of Bays 2 Printer Server Rack-mount or Standalone Standalone RAID Level JBOD RAID Level RAID 0 RAID Level RAID 1 RAID Level single Remote Access UPnP Capable Wired Network Speed 10/100/1000 Learn More QNAP TS-233 Review -
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![Asustor Drivestor 2 Gen2 AS1202T]()
Best Budget NAS DeviceAsustor Drivestor 2 Gen2 AS1202T
Pros & Cons
Why We Picked It
An entry-level backup and storage solution for home use, the Asustor Drivestor 2 Gen2 AS1202T is a reasonably priced two-bay NAS drive that offers multi-gig LAN connectivity, three 5Gbps USB ports, and more than 150 productivity and multimedia apps in its store. It’s a solid performer, and is easy to install and manage thanks to a tool-free enclosure and Asustor’s user-friendly ADM operating system. An HDMI port would be welcome, but at this price, it’s hard to complain.
Who It’s For
Budget-conscious home users: At less than $200, the AS1202T is an affordable two-bay NAS designed for anyone who prefers to store data in their own personal cloud rather than pay for a subscription-based cloud service.
Newbies: This NAS is easy to manage using the Windows-like ADM operating system, making it ideal for beginners who are unlikely to miss the multiple LAN and HDMI ports that you get with more expensive NAS devices.
Specs & Configurations
Bay Size 3.5-inch Connection Type 2.5GbE Connection Type USB 3.2 (3) External USB Hard Disk Expansion Hard Disk Configuration RAID 1 Media Server Network Medium Wired Number of Bays 2 Printer Server Rack-mount or Standalone Standalone RAID Level JBOD RAID Level RAID 0 RAID Level RAID 1 RAID Level single Remote Access UPnP Capable Wired Network Speed 10/100/1000/2.5GbE Learn More Asustor Drivestor 2 Gen2 AS1202T Review -
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Credit: Joseph Maldonado
![Asustor Lockerstor 2 Gen2+ (AS6702T v2)]()
Best Two-Bay NAS Device for Power UsersAsustor Lockerstor 2 Gen2+ (AS6702T v2)
Pros & Cons
Why We Picked It
The Asustor AS6702T v2 uses high-speed components—including a solid state drive (SSD) cache—to deliver outstanding performance. This two-bay NAS features four M.2 slots for installing NVMe SSDs; M.2 slots are becoming more common, but many drives that offer them just have two. It's rare to see four on a consumer-oriented drive. By adding high-speed SSD modules in these slots, you can cache and accelerate data access for content creation and other labor-intensive tasks. Link aggregation and 4K video transcoding are also supported.
Who It's For
People with a lot of data to back up: If you’re in the market for a powerful two-bay NAS for content creation, personal cloud storage, or as a data backup repository, look no further than the AS6702T v2.
Power users who want speedy storage: Few competitors offer four M.2 slots for speedy caching, so this is the go-to two-bay NAS for content creators and power users.
Specs & Configurations
Bay Size 2.5 and 3.5-inch Connection Type 5GbE (2) Connection Type HDMI Connection Type USB 2.0 Connection Type USB 3.2 (2) External USB Hard Disk Expansion Hard Disk Configuration RAID 1 Media Server Network Medium Wired Number of Bays 2 Printer Server Rack-mount or Standalone Standalone RAID Level JBOD RAID Level RAID 0 RAID Level RAID 1 RAID Level single Remote Access UPnP Capable Wired Network Speed 10/100/1000 2.5GbE/5GbE -
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![Asustor Lockerstor 4 Gen 3 (AS6804T)]()
Best Four-Bay NAS Device for Power UsersAsustor Lockerstor 4 Gen 3 (AS6804T)
Pros & Cons
Why We Picked It
When it comes to ports and performance, the pricey Asustor AS6804T is a class leader. It delivers blistering file transfer speeds alongside an excellent assortment of I/O ports—four multi-gig LAN ports and five high-speed USB ports—and a powerful AMD Ryzen CPU. It also offers multiple RAID configurations and four M.2 slots that can be populated with NVMe solid-state drives for additional speedy storage or caching. You’ll have to supply your own drives, but that’s the case with nearly every NAS device that we test.
Who It’s For
Small businesses: The AS6804T is designed for home offices and small businesses that require speed, expandability, and ease of use.
People who need customized NAS functions: The AS6804T delivers excellent performance and comes with more than 200 apps for backing up data, using the NAS as a cloud or media server, storing and organizing photos, and much more.
Specs & Configurations
Bay Size 2.5 and 3.5-inch Connection Type 10GbE (2) Connection Type 5GbE (2) Connection Type USB 3.2 (3) Connection Type USB 4.0 Type-C (2) External USB Hard Disk Expansion Hard Disk Configuration RAID 5 Media Server Network Medium Wired Number of Bays 4 Printer Server Rack-mount or Standalone Standalone RAID Level JBOD RAID Level RAID 0 RAID Level RAID 1 RAID Level RAID 10 RAID Level RAID 5 RAID Level RAID 6 RAID Level single Remote Access UPnP Capable Wired Network Speed 10/100/1000 2.5GbE/5GbE/10GbE Learn More Asustor Lockerstor 4 Gen 3 (AS6804T) Review -
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Credit: Joseph Maldonado
![Synology DiskStation DS1525+]()
Best Five-Bay NAS Device for Power UsersSynology DiskStation DS1525+
Pros & Cons
Why We Picked It
Whether you’re a home user looking to store multimedia files and share them in the cloud, or a small business that requires a scalable storage solution with multiple RAID options, the Synology DiskStation DS1525+ NAS is an excellent choice thanks to its five drive bays. (That's more than most other small-business NAS devices offer.) Plus, you get two embedded M.2 NVMe SSD cache slots, and the ability to add 10 more drives via an expansion unit.
Who It's For
Small businesses: For many businesses, scalability is the name of the game when it comes to network storage. The DS1525+ delivers scalability in spades.
People with cutting-edge networking components: This five-bay NAS is also a great choice for homes and businesses with cutting-edge networking components, since you can outfit it with a 10Gbps LAN adapter for high-speed network connectivity.
Specs & Configurations
Bay Size 2.5 and 3.5-inch Connection Type 2.5Gbe (2) Connection Type USB 3.2 (2) External USB Hard Disk Expansion Hard Disk Configuration SHR Media Server Network Medium Wired Number of Bays 5 Printer Server Rack-mount or Standalone Standalone RAID Level JBOD RAID Level RAID 0 RAID Level RAID 1 RAID Level RAID 10 RAID Level RAID 5 RAID Level RAID 6 RAID Level SHR RAID Level single Remote Access UPnP Capable Wired Network Speed 10/100/1000/2.5GbE Learn More Synology DiskStation DS1525+ Review -
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![LatticeWork Amber X]()
Best Single-SSD NAS DeviceLatticeWork Amber X
Pros & Cons
Why We Picked It
LatticeWork's Amber X is a single-drive, SSD-based NAS that makes it easy to back up your files to a private personal cloud. It's a snap to set up, and it includes many helpful software features to streamline your digital life, including AI facial recognition that can organize your photo library. It's also quite portable. At just 0.6 pounds, the Amber X is small and light enough to take along wherever you go, if you are so inclined. Inside, it has a 512GB SSD for its only storage drive, which will fill up quickly if you store a lot of high-res pics and videos, but you can add storage by connecting an external drive to the gadget's USB 3.1 port.
Who It's For
Friends who share photos: The Amber X makes it easy to back up your photos, videos, and other important data so you can share them with family and friends.
Frequent travelers: This NAS is small enough to take on the road, and it supports TV casting and media streaming, too, making it an excellent choice for anyone who needs a versatile network-connected backup and storage solution for personal use.
Specs & Configurations
Connection Type Ethernet External USB Hard Disk Expansion Media Server Network Medium Wired Network Medium Wireless Rack-mount or Standalone Standalone Remote Access UPnP Capable Wired Network Speed 10/100/1000 Learn More LatticeWork Amber X Review -
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![TerraMaster F8 SSD Plus]()
Best Multi-SSD NAS DeviceTerraMaster F8 SSD Plus
Pros & Cons
Why We Picked It
The TerraMaster F8 SSD Plus is an eight-bay NAS device that uses M.2 NVMe SSD drives to deliver fast, whisper-quiet networked storage. It doesn't take up a lot of desktop space, and our extensive testing shows that it's easy to install and configure. At $800 (without the drives), it doesn't come cheap, but its rarified price reflects that NAS drives with this many bays and M.2 support are few and far between.
Who It's For
Cramped offices: The TerraMaster F8 SSD Plus is a good choice for home power users or small businesses that require the speed of an SSD NAS but don’t have much desktop real estate.
People seeking set-it-and-forget-it ease: This NAS aced our performance tests and is easy to manage using TerraMaster's TOS 6 operating system.
Big spenders: Its $800 price is prohibitive, and it'll cost a lot more than that if you populate it at maximum capacity, so it's only a good choice if you've got a healthy budget.
Specs & Configurations
Bay Size M.2 NVMe Connection Type 10GbE Connection Type HDMI Connection Type USB 3.2 (2) Connection Type USB-C External USB Hard Disk Expansion Hard Disk Configuration TRAID Media Server Network Medium Wired Number of Bays 8 Printer Server Rack-mount or Standalone Standalone RAID Level JBOD RAID Level RAID 0 RAID Level RAID 1 RAID Level RAID 10 RAID Level RAID 5 RAID Level RAID 6 RAID Level single RAID Level TRAID RAID Level TRAID + Remote Access UPnP Capable Wired Network Speed 10/100/1000/2.5GbE/10GbE Learn More TerraMaster F8 SSD Plus Review -
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![Zettlab D4 AI NAS]()
Best AI-Augmented NAS DeviceZettlab D4 AI NAS
Pros & Cons
Why We Picked It
The Zettlab D4 AI NAS is a four-bay NAS that delivers snappy performance alongside AI-powered search and photo management features. It's a breeze to set up, and it delivers very fast performance in our testing. You can install up to 100TB of storage using four 24TB platter drives and a 4TB M.2 SSD. Plus, you can snap it up for $700—not terribly expensive for a four-bay NAS, and it's often discounted.
Who It's For
AI early adopters: Robust AI features aren't common in the NAS market (yet), so the D4's AI capabilities set it apart. With AI Search, you can hunt for photos, videos, and documents using natural-language entries, and Knowledge QA lets you ask questions and receive answers based on your stored data. The Photo Album, meanwhile, uses AI to categorize and index photos and videos.
College students and educators: Auto Transcription and AI Clip features convert classroom lectures (and other audio, such as work meetings or personal recordings) into text notes.
Specs & Configurations
Bay Size 2.5 and 3.5-inch Connection Type 1GbE Connection Type 2.5GbE Connection Type HDMI Connection Type USB 2.0 (2) External USB Hard Disk Expansion Hard Disk Configuration RAID 5 Media Server Network Medium Wired Number of Bays 4 Printer Server Rack-mount or Standalone Standalone RAID Level Basic RAID Level JBOD RAID Level RAID 0 RAID Level RAID 1 RAID Level RAID 10 RAID Level RAID 5 RAID Level RAID 6 Remote Access UPnP Capable Wired Network Speed 10/100/1000/2.5GbE Learn More Zettlab D4 AI NAS Review -
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Best For | Best Single-Drive NAS Device for Most People | Best Two-Bay NAS Device for Most People | Best Budget NAS Device | Best Two-Bay NAS Device for Power Users | Best Four-Bay NAS Device for Power Users | Best Five-Bay NAS Device for Power Users | Best Single-SSD NAS Device | Best Multi-SSD NAS Device | Best AI-Augmented NAS Device | Best Single-Drive NAS Device for Most People | Best Two-Bay NAS Device for Most People | Best Budget NAS Device |
Connection Type | 1GbE, USB 3.2, USB-C | Ethernet, USB 2.0, USB 3.0 | 2.5GbE, USB 3.2 (3) | USB 3.2 (2), USB 2.0, 5GbE (2), HDMI | 10GbE (2), 5GbE (2), USB 4.0 Type-C (2), USB 3.2 (3) | 2.5Gbe (2), USB 3.2 (2) | Ethernet | 10GbE, USB 3.2 (2), USB-C, HDMI | 2.5GbE, 1GbE, HDMI, USB 2.0 (2) | 1GbE, USB 3.2, USB-C | Ethernet, USB 2.0, USB 3.0 | 2.5GbE, USB 3.2 (3) |
RAID Level | None | JBOD, single, RAID 0, RAID 1 | JBOD, single, RAID 0, RAID 1 | JBOD, single, RAID 0, RAID 1 | JBOD, single, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 | SHR, JBOD, single, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 | TRAID, TRAID +, single, JBOD, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 | JBOD, Basic, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 | None | JBOD, single, RAID 0, RAID 1 | JBOD, single, RAID 0, RAID 1 | |
Hard Disk Configuration | Fixed Single | RAID | RAID 1 | RAID 1 | RAID 5 | SHR | TRAID | RAID 5 | Fixed Single | RAID | RAID 1 | |
Network Medium | Wired | Wired | Wired | Wired | Wired | Wired | Wired, Wireless | Wired | Wired | Wired | Wired | Wired |
Rack-mount or Standalone | Standalone | Standalone | Standalone | Standalone | Standalone | Standalone | Standalone | Standalone | Standalone | Standalone | Standalone | Standalone |
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Wired Network Speed | 10/100/1000 | 10/100/1000 | 10/100/1000/2.5GbE | 10/100/1000 2.5GbE/5GbE | 10/100/1000 2.5GbE/5GbE/10GbE | 10/100/1000/2.5GbE | 10/100/1000 | 10/100/1000/2.5GbE/10GbE | 10/100/1000/2.5GbE | 10/100/1000 | 10/100/1000 | 10/100/1000/2.5GbE |
Number of Bays | 1 | 2 | 2 | 2 | 4 | 5 | 8 | 4 | 1 | 2 | 2 | |
Bay Size | 2.5 and 3.5-inch | 3.5-inch | 2.5 and 3.5-inch | 2.5 and 3.5-inch | 2.5 and 3.5-inch | M.2 NVMe | 2.5 and 3.5-inch | 2.5 and 3.5-inch | 3.5-inch | |||
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Buying Guide: The Best NAS (Network Attached Storage) Devices for 2026
How Do I Choose a NAS Device?
Once you decide you need to store files on a network drive, you need to figure out what you plan to do with them to determine which kind of NAS you need.
For example, a typical business scenario might involve sharing access to Office files, such as spreadsheets and Word documents, with your coworkers, and backing up select devices on a regular basis. All of that is relatively simple for a NAS. Ensuring additional layers of data security and serving files to a relatively large number of users are typically where businesses need to be careful about NAS storage.
Home users may not need to worry about large numbers of users; these days, it's the number of simultaneous devices that matters. If you're using the NAS to back up your laptops overnight, that's pretty straightforward. But if you're serving high-resolution videos over your home network to two tablets, a laptop, and your smart TV simultaneously, you'll want a NAS with higher specifications for memory, processor, and network performance. You'll also need a more powerful NAS if you want to store large media libraries, like a collection of 100,000 stock photos for your graphic arts studio.
(Credit: Joseph Maldonado)Since a NAS device is, at the simplest level, just a container for a hard drive or drives (with some added intelligence), the number-one spec for any NAS unit is its maximum potential storage capacity. That's determined by the number of drive bays it includes and, to a lesser extent, what kinds of drives it can carry. Most consumer-grade and home-office NAS units have one or two bays, while office-grade models have four or more. But that's not an absolute guideline, especially now that some NAS devices are showing up with support for 2.5-inch laptop-style drives, both platter-based and solid state. These drives will allow NAS makers to fit more drives into their chassis, or the same number of drives into a smaller chassis.
We don't generally recommend NAS drives with a single bay, unless they are to be used strictly for backing up data that will also reside on network computers. That's because there's no redundancy out of the box. (Some single-bay NAS drives will allow you to attach a second NAS device or an external hard drive to that end.) You don't want the only copy of your data residing on just one drive on the network.
The beauty of a NAS device is that it can use some version of a technology called Redundant Array of Independent Disks (RAID). This tech allows the software that manages the NAS devices to distribute and duplicate the data it stores across multiple hard disks. That means even if one of the drives fails completely, the RAID system can simply replace it with a new, empty drive and reconstruct the data the failed drive held. Different RAID levels perform this function in different ways (and note that some lack the redundancy/safety aspect), depending on exactly what users need. Check out our RAID explainer for more information.
Still, for most home users who aren't rabid video-file hoarders, a two-bay NAS should be sufficient, provided that you buy big enough drives from the outset if you'll be mirroring them, meaning simply making one drive an exact duplicate of the other. Err on the high side of capacity, though; it'll cost more now, but you don't want to have to rebuy two hard drives for your NAS to get a higher effective mirrored capacity. Remember: Mirroring takes two physical drives. More on redundancy below.
Should I Buy a NAS With Drives Installed, or Diskless?
Some NAS drives are sold pre-populated with disks, oftentimes already formatted for use in a particular RAID configuration. Many others are purchased empty of drives, or "diskless." This was an important consideration some years ago because NAS vendors who also manufactured hard drives would ship their NAS units as sealed devices, pre-filled with their own drives. Today, most current NAS devices are disk-brand-neutral. Because most of these devices at least offer a diskless option, you're really only concerned with overall drive capacity, their interface technology, and how much they'll add to the overall cost of your NAS.
(Credit: Joseph Maldonado)If a given NAS is offered in both pre-populated and diskless forms, we suggest comparing the costs and ensuring that the drives provided in the populated model are a good value. With pre-populated-only NAS drives, the cost of the internal drives is harder to distinguish from the overall cost of the NAS unit.
Which Drives Should I Use With a NAS?
NAS makers that sell diskless NAS drives recommend certain drive models or families that have been tested for use with their NAS drives. Take a look at these drive-compatibility lists before you buy. If you already own a bank of hard drives you intend to install, you'll want to look for such validation. If yours aren't on the list, that doesn't mean they won't work, but if you are buying new drives, it's best to stick with the NAS maker's recommendations.
Some drives from Seagate, Toshiba, and WD are tagged as specially designed for NAS use. Most of these "NAS certified" hard drives have been tested to run 24/7/365, which is a bit much for regular, consumer-level drives.
(Credit: Joseph Maldonado)If you are looking at Seagate drives, for example, the NAS-class drives are called the IronWolf, IronWolf Pro, IronWolf SSD, and IronWolf SSD and HDD lines. Straight IronWolf drives are what you're after for outfitting a home NAS. IronWolf Pro is designed for somewhat heavier business use, while IronWolf SSD is meant for NAS units that need solid-state speed to serve up data quickly for high-performance applications. The last, the IronWolf SSD and HDD drives, combine both technologies in a single drive that then has its own firmware logic to distribute data for optimal performance beyond what SSD delivers on its own.
Other drive makers will have similar products with comparable storage and interface technologies, though they'll differ somewhat in capacity and pricing. WD's NAS-oriented equivalents to the IronWolfs, for example, are dubbed WD Red. One other hard drive-related proviso: Watch for NAS models that require specific hard drive brands. Notably, some late-model Synology NAS units now require Synology-branded hard drives or SSDs. Often, NAS makers will provide a list of recommended or vetted drive models, but this move goes a step further.
Know also that an emerging class of NAS drives employs either a combination of M.2 SSDs and hard drives, or purely M.2 SSDs. These "gumstick" drives are very compact and can be used in some NAS drives as caches to speed up access to hard drives installed alongside them. Some other NAS units, though, use M.2 solely for high-speed primary storage, and these NAS devices tend to be pretty compact compared with most, since they don't need to hold bulky 3.5-inch platter drives. If you're looking at a NAS device with M.2 support, make sure you know the difference: whether the M.2 is meant as a cache or as the main storage. In some models, you may have the option to have the M.2 function as one or the other.
RAID, and RAID Again: Let's Talk Redundancy
As we mentioned earlier, a key benefit of most NAS units is the redundancy option, so in two- and four-drive configurations, the extra disks can simply "mirror" the contents of the other drive or drives. Depending on which RAID level you choose (more about the different levels in a moment), this will impact the overall capacity of the NAS device versus the hard disks it has installed. Example: A two-bay unit with two 4TB drives that mirrors one drive onto the other would offer only 4TB of effective (usable) storage. The other drive is, in a practical sense, invisible, because in the background, it's used to make a second copy of all the files from the other drive.
You can also configure your NAS to use the full capacity of all its drives, if desired. One way you can do this is via "striping," in which the data will span across two or more drives. Striping by itself is chancy; under some circumstances, it enhances the speed of reads and writes, since you're accessing two or more drives at once. But if any one disk fails, all your data could be lost, so we don't recommend this approach. (With your data spanning across two or more drives, you now have multiple points of failure.)
RAID modes that incorporate striping and mirroring are much safer, as that guarantees that each bit of data is replicated on at least two drives, so that if one drive in the array fails, the NAS can reconstruct its contents onto a replacement drive. Of course, this requires some redundancy and reduces the overall capacity available to the drives.
RAID Levels Explained
In short, for basic NAS use, the key RAID types are called RAID Level 0, 1, and 5. RAID Level 0 is straight-up striping, with your data spread across several drives for speed, with no redundancy. (Think of it as "zero margin for safety" if a drive fails!) RAID Level 1 is simple mirroring, with 1:1 copies maintained across two or more drives and full redundancy. There's no speed benefit to RAID 1 but full safety in case of a drive failure. RAID Level 5 delivers the best of both worlds, with mirroring and striping implemented across at least three hard drives; if one drive fails, you can reconstruct its contents to a replacement from the bits of it on the drives that are still working. (There's also RAID Level 10, where you have mirrored pairs that are also striped; it requires at least four drives.)
Many NAS units also support a JBOD mode ("Just a Bunch of Disks"), which lets you address each drive as a separate drive letter and save data to discrete drives within the NAS box. This is not much safer than striping; any data you save to a given drive is still vulnerable to the failure of that specific mechanism. To mitigate this, some JBOD NAS management software allows users to combine disks into one or more logical volumes and even apply redundancy measures across volumes. This is usually entirely dependent upon the software used to manage the NAS, however, so be sure to understand your NAS drive's software capabilities before purchase, particularly if you're a small-business buyer.
What to Know About Media Streaming From a NAS
If you think a NAS drive will let you stream any type of media you have to any device or TV, keep in mind that not all devices can play all file types, and you'll need to get software and hardware to work together to make this happen.
For example, that, ahem, sweet DVD rip you have of James Cameron's Titanic in AVI format will not open on an iPhone without some jiggering. (It needs to be in MP4 format to be recognized.) Software can get around that problem, such as the ever-useful VLC Media Player utility, and some NAS units work with Apple TV, Chromecast, Roku, Android phones/tablets, and other types of hardware. It can be tricky to guarantee that a specific file or file type will play on a given device, so review the NAS's specs to determine its capabilities.
(Credit: Synology)A relatively recent development in NAS circles is a special kind of support for streaming 4K video, and the spec sheet is your friend in these cases. Some NAS units with 4K acceleration will convert this high-resolution video on the fly to formats better suited to the bit rates of destination devices, such as smartphones, that are requesting it. This is an esoteric need at the moment, but know that some NAS makers will charge a premium for some of these features. It's also possible to get such on-the-fly transcoding for other, lesser resolutions. This is where the CPU that powers a NAS can come into play: say, a low-end dual-core chip versus a much more robust quad-core processor.
NAS Connectors and Controls: What to Look For
Most NAS drives have one or two USB ports that you can use to connect a printer or external storage drive, letting you add those to your network via the NAS itself. Once they are plugged in, they can be shared with all connected users, just like everything else on the NAS. An example of a common arrangement: A NAS drive has one USB 2.0 port, usually used for printer sharing, and one USB 3.0 port, which can be used for external storage. (USB 2.0 is much, much slower than USB 3.0, but a printer doesn't need the fast pipe, so a USB 2.0 port is just fine for that.)
(Credit: Joseph Maldonado)Some NAS units also have a "copy" button on the front panel that makes copying the contents of an external drive, such as a flash drive, to the NAS a single-button-press affair. You just connect the drive and tap the button, and everything on the external drive is safely copied to the NAS in a pre-designated location.
By definition, NAS drives will come with at least one Ethernet jack, and sometimes two, for redundancy or channel bonding. (The latter, essentially, combines two smaller Ethernet pipes into one logical, large pipe.) NAS drives avoid wireless connectivity because only wired connections provide the smooth traffic flow they need to serve data, especially streaming data, to multiple recipients at optimal rates.
(Credit: Joseph Maldonado)Recent high-end models go so far as to offer 10-gigabit Ethernet for screaming data transfer rates. However, this only makes a difference if the rest of the network is running at 10Gbps (or at least the primary traffic target is). Additionally, the throughput of platter hard drives makes this moot for most consumer and small-office use cases. That said, a few models come with a PCI Express slot that may let you install an enhanced network card. And as mentioned earlier, others support using SSDs instead of hard drives, or in addition to hard drives (a configuration in which the SSDs are used for caching and the hard drives are used for storage), for faster throughput.
A few models will also include an HDMI port, letting you use the NAS as a media server with a direct connection to your HDMI-equipped HDTV.
Remote Access: Serving Files From Here to Anywhere
In addition to the above sharing features, most NAS drives let you send web links to others so they can access specific files or folders on your NAS. Your NAS can thus serve as your own private Dropbox or Google Drive, with way more storage—and no monthly bill. Many NAS makers tout this. (Look for the much-bandied term "personal cloud" around this kind of feature.)
How each vendor offers this capability, however, can vary. Some may do as little as offer a simple File Transfer Protocol (FTP) manager as an app or as a command-line feature. This will certainly work, but you'll need to know how to configure a secure FTP server to make sure your files aren't suddenly exposed to the whole internet. Most NAS devices now offer a Windows-like app that handles remote internet access. These come with easy-to-learn user interfaces and more advanced security options, including the ability to encrypt files you're uploading to the cloud.
With this functionality, you can also access the NAS itself from any internet connection, not just via your local network. As a result, you can download the files you need on the road, or stream movies or music from your home NAS to your laptop in a hotel across the country or the world, network bandwidth permitting. Most, but not all, NAS drives offer this kind of feature, so be sure to do your research before you pull the trigger if it's a must-have. (Ourselves? We wouldn't get a NAS without it.)
Ready to Buy the Right NAS Drive for You?
One of our top recommendations in this guide is almost certain to fit your network-attached storage needs. But what if a NAS device is not quite right for what you want? For more storage options, check out our selections of the best external hard drives and top external SSDs we've tested, as well as our top-rated cloud storage services.