Unfettered File Access From Anywhere
In this age of high-resolution photos and near-constant video capture, the storage space in your PCs and mobile devices fills up faster than ever. While you can certainly use an external hard drive for offloading and backing up files from your PC (and by extension, from your phone), if you disconnect the hard drive and leave it in your office, you won’t be able to get to those files from home, and neither will anyone else. There are ways to allow other users to share and access the files on your hard drive, but they may be challenging to implement, or carry security risks.
Instead, consider a good network-attached storage (NAS) device. As its name implies, a NAS is high-capacity storage that connects to your home or office network so that you and other users you designate can access your files from mobile devices and PCs without plugging in to the drive. Here’s what you need to know to choose the right NAS.
What Can You Do With a NAS?
Once you decide that you need to store files on a network drive, you then need to figure out what you mean to do with them, in order to determine what kind of NAS you need.
For example, sharing access to Office files like spreadsheets and Word documents with your coworkers is a simple job for a NAS. If you’re using the NAS to back up your laptops overnight, that’s pretty straightforward, as well. But if you’re serving HD videos over your home network to two tablets, a laptop, and your smart TV, all at the same time, you’ll want a NAS with higher specifications for memory, processor, and network capabilities. You’ll also need a more powerful NAS if you want to store big media libraries, like a collection of 100,000 stock photos, for your graphic arts studio.
Like any computer peripheral, the features offered by the various NAS units vary greatly to meet these different demands. So you’ll need to understand the terms and features before you go shopping.
NAS Drives: Buying Basics
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 potential storage capacity, determined by the number of drive bays it includes. Most consumer-grade and home-office NAS units have one or two bays, while models designed for the office have four or more. But that’s not an absolute guideline.
We don’t generally recommend NAS drives with just a single bay, unless they are to be used strictly for backing up data that will also reside on computers on the network. That’s because of the lack of 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. Also, the drives in these single-bay devices tend not to be user-accessible, if the NAS ships with a drive pre-installed.
For most home users who aren’t 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. 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 in a moment.
Buying a NAS: Populated or Diskless?
Some NAS drives are sold pre-populated with disks, oftentimes already formatted for use in a particular RAID configuration, while others come “diskless.” Each NAS vendor has its own tendencies in that regard. But surprise, surprise: The NAS-device makers who are also manufacturers of hard drives (Seagate, Western Digital) favor pre-populated NAS drives for obvious reasons—they lock in a sale of their own hard drives when they sell a NAS. (Not an insidious motive, mind you, just good business.) The “indie” NAS makers that aren’t drive manufacturers, such as Synology and QNAP, are more likely to sell their NAS devices diskless, though they (or more accurately, their resellers) may also offer units pre-populated and configured with drives for shoppers’ convenience.
If a given NAS is offered in both pre-populated and diskless form, we suggest checking out the cost difference and making sure that the drives that are provided in the populated model work out to a good value. With pre-populated-only NAS drives from Seagate and WD, the cost of the internal drives tends to be harder to distinguish from the cost of the NAS unit.
Which Drives to Use Inside Your NAS?
NAS makers that sell diskless NAS drives recommend certain drive models or families that have been tested for use with their NAS drives. This might coincide with the hard drives they actually manufacture, or not. 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 are not on the list, it doesn’t mean they won’t work, but if you are buying drives new, it’s best to stick with the NAS maker’s recommendations.
Some drives from HGST, 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.
If you are looking at Seagate drives, the NAS-class drives are called the “IronWolf” and “IronWolf Pro” lines. Straight IronWolf drives are what you’re after for outfitting a NAS drive in a home; they come in 1TB to 14TB capacities, at this writing. IronWolf Pro drives are rated for service in enterprise or commercial situations. HGST’s drives are the Deskstar NAS line, and Toshiba’s are in the “N” series. On the Western Digital side, the NAS-specific drives are the “WD Red,” in capacities from 1TB to 10TB, with the “WD Red Pro” series meant for enterprise use.
Safe (Storage) Space: Let’s Talk Redundancy
As we mentioned earlier, NAS units that have more than one drive are built to offer the option for redundancy, so in two- and four-drive configurations the extra disks can simply “mirror” the contents of the other drive. Example: A two-bay unit with two 4TB drives would offer only 4TB of usable storage if you leave it in mirror mode. The other drive is in a sense invisible, as it’s used to make a second copy of all the files from the other drive in the background.
Usually, the user has the option to reconfigure the drives to gain the capacity of the second drive, if desired. One way you can do this is via “striping,” in which the data will span both drives. Striping by itself is chancy; under some circumstances, it enhances the speed of reads and writes, since you’re accessing two drives at once. But if either disk fails, it’s possible that all your data will be lost, so we don’t recommend this approach. It essentially doubles the failure risk.
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 marginally safer than just basic striping, but any data you save to a given drive is still vulnerable to the failure of that specific mechanism.
It’s also possible to combine striping and mirroring across three or more drives for enhanced speed and data security. In such an arrangement, the NAS would copy the data across the drive array in such a way that the failure of one of the drives would allow the NAS to reconstruct the array (and thus save your data) if you swap in a replacement drive. This is mainly of interest to business users that need to maximize both redundancy and data transfer rates.
If you think a NAS drive will let you stream any type of media you have to any device or TV, keep in mind certain devices will only play certain types of files, 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 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 Chromecast, Apple TV, Roku, Android phones/tablets, and other types of hardware. It can be complicated, though, to guarantee that a specific file or file type will play on a given device, so look at the specs of the NAS closely to determine its capabilities.
A late development in NAS circles is special kinds of support for streaming 4K video, and the spec sheet is your friend in these cases. Some NAS with 4K acceleration will convert this high-resolution video on the fly to formats better suited to the bit rates of 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 comes into play: a low-end Intel Atom versus a much more robust Core i3, for example.
Connectors and Controls
Most NAS drives have one or two USB ports that you can use to connect a printer or external storage drives, letting you add those to your network via the NAS itself. Once they are plugged in, just like everything else on the NAS, they can be shared with all the connected users. A frequent arrangement: A NAS drive will have one USB 2.0 port that is usually used for printer sharing, and a USB 3.0 port that 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.)
Some NAS units also have a “copy” button on the front panel designed to make copying the contents of an external drive, such as a flash drive, to the NAS a one-button-press affair. You just connect the drive and tap the button, and everything on the external drive is safely copied to the NAS to a predesignated location.
NAS drives, by definition, will come with an Ethernet port, possibly two for redundancy or channel-bonding (essentially, using two Ethernet connections to enhance speed) with very high-end business models. Recent high-end models may also offer the option for 10-gigabit Ethernet, for screaming data transfer rates, though the throughput of platter hard drives makes this moot for most consumer and SOHO usage cases. (That said, a few models come with a PCI slot that may let you install an enhanced network card.)
A few models will also come with an HDMI port; this would let 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 people to allow them to access remotely certain files or folders located on your NAS. Your NAS can thus serve like your own private Dropbox or Google Drive, but with way more storage capacity—and no monthly bill. Many NAS makers tout this. (Look for the much-bandied term “personal cloud” around this kind of feature.)
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 files you need on the road, or stream a movie or music files resident on 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.)
Below are the top NAS devices we’ve recently tested, ranging from simple home-oriented models to multiple-drive arrays that can serve dozens of users in an office environment. Whether you want to serve media files to the rest of the house, keep office documents in a single, accessible repository, or simply back up your digital life from your PCs, tablets, and mobile phones, there’s a drive here for you.
Pros: Speedy performance. Easy setup. Lots of ports. Supports 4K video transcoding and IFTTT automations. Generous selection of apps.
Cons: Drives not included.
Bottom Line: The QNAP TS-251B-4G is a speedy, easy-to-use dual-drive NAS device equipped with a generous supply of ports and apps.
Pros: Easy to install. Offers 4K video transcoding. Supports numerous RAID configurations. Generous port selection. Loads of apps.
Cons: Does not come with hard drives.
Bottom Line: The Synology DiskStation DS718+ is a versatile, feature-packed two-drive NAS that delivers solid performance.
Pros: Speedy performance. Easy to install. Generous selection of apps. Lots of RAID choices. User-friendly operating system. Quiet operation.
Bottom Line: The Synology DiskStation DS1019+ is a five-bay NAS device that offers speedy performance and valuable features, including support for numerous RAID configurations, 4K video transcoding, and a host of apps.
Pros: Easy to configure. Fast performance. 10Gb Ethernet. Tool-free drive installation. Massive app catalog.
Cons: Drives not included. Limited I/O ports. Slightly noisy.
Bottom Line: The Asustor AS4002T is a feature-packed dual-drive NAS that performs well and is easy to install and configure.
Pros: Very easy to install and manage. Robust apps. Stylish design. Reasonably priced.
Cons: Middling file-transfer performance in testing. Does not come with hard drives.
Bottom Line: The Synology DiskStation DS218j is an excellent entry-level two-bay NAS device that’s supported by a bevy of management options and third-party apps.
Pros: Easy to install and manage. Small footprint. Quiet. Solid performance. Lots of available apps.
Cons: Only accepts 2.5-inch drives. Limited storage capacity. Drives not included.
Bottom Line: The Synology DiskStation DS419slim is a small but powerful four-bay network-attached storage device that offers many of the same features found on bigger, more expensive models.
Pros: 4K video output. USB Type-C connectivity. User-friendly web and mobile management apps. Supports lots of third-party apps.
Cons: Pricey. Middling file transfer speeds. Finicky installation process.
Bottom Line: The Asustor AS6302T is a two-bay NAS device that offers an admirable port selection and feature set, but it can be tricky to install and its file-transfer speeds are mediocre.
Pros: Easy to set up, access, and share. Automatically uploads phone camera roll.
Cons: Somewhat sluggish. Not for power users. Can’t map drive for direct access. Must use apps to access storage.
Bottom Line: The 4-terabyte Promise Apollo is a personal cloud device that connects to your router and automatically downloads and saves photos and videos from your smartphone or tablet, so you can make more room on your devices.
Pros: Easy to install and use. Stylish design. Mobile and web user interface. Automatic camera roll backup.
Cons: Drives are not easily accessible. Short on features. Middling file-transfer performance.
Bottom Line: The Promise Apollo Cloud 2 Duo is a simple, good-looking NAS device that offers copious easy-to-use personal cloud storage, although it’s a bit slower than the competition.
Pros: Supports 4K video transcoding. Lots of I/O ports. Includes mobile app. Solid file-transfer performance.
Cons: Finicky setup procedure. Poor documentation. Limited apps.
Bottom Line: The TerraMaster F2-221 is a dual-drive NAS that performs well and comes with some helpful features, but it’s hampered by a difficult setup process and meager tech support.