2017 Guide: The Best NAS Drives for Homes and Small Offices

The Whats & Whys of NAS

First off: What is a network attached storage, or NAS, device? In its simplest form, it's a hard drive or hard drives in a box, connected to your router. Inside the chassis is a small motherboard, with a CPU and some memory to control its functions, plus a power supply. That’s all there is to it—like we said, a simple concept wrapped in opaque terminology.

The main benefit of a NAS drive is that anyone who is connected to the router for his or her Internet connection, either wired or wirelessly, can access the hard drive. As a result, the NAS can act as a central, local repository for files, media, and anything else that needs to be shared by multiple folks all using the same network. Advanced features in today's routers also let you extend that file-sharing access to people outside your local network, in essence letting you host your own "personal cloud." (That's a term NAS makers throw around—a lot.)

The much cheaper alternative to installing a NAS is to set up file sharing directly on an individual’s computer, then configure the settings to allow other people to connect to those files or folders. File sharing in that way presents several issues and limitations, though. First, it's possible that either the person sharing the files or the person wanting to connect to his or her computer will not understand how to do this—setting up file sharing under Windows or macOS can be cumbersome. Second, if the person sharing the files has his or her computer powered off, then nobody can access the file content on it. Third, the entire arrangement is limited by the amount of storage space the hosting party has on his or her computer.



Good basic two-bay NAS: Drobo B810n

Network attached storage overcomes these limitations of traditional file sharing by giving all users who are connected to a router a centralized storage pool for everyone to share, 24/7, that will usually exceed in size the local storage on their PCs. In addition, some NAS drives are easy to upgrade to meet growing storage demands, via user-accessible bays in the chassis. With a drive like this, if the capacity you choose becomes inadequate down the road, it’s usually a trivial matter to add more and/or bigger hard drives by inserting them into empty bays in the chassis.

A well-designed NAS drive also makes granular file sharing easy, as the NAS drive's software—usually, a Web-based interface that you tweak through a browser—allows you to dictate and customize access rights. If the software is designed right (and it has gotten a lot better in recent years, from most NAS players), that's done easily. So, for example, you can share your NAS-resident music or file collection, or common-access work files, across a network, but lock down the financial stuff or personal files in private folders. The process of accessing the NAS drive is usually akin to adding a hard drive to your own computer; it’s just another drive that shows up alongside the rest, even though it’s connected through the network.

These days, NAS drives are designed to make media streaming, i.e. viewing or playing content without downloading it, super-simple, too. Music is no challenge for a modern NAS unit, nor video up to 1080p. Streaming very big video files these days, though, requires a bit of discernment. For example, with certain appropriately equipped NAS devices, you can stream a 4K video from the NAS to your tablet or phone via your home network, with the NAS performing some on-the-fly processing to make the file palatable to your device. This might be impossible, otherwise, due to the storage and bandwidth limitations of a mobile device. But that's where NAS nuances (and following from that, we) come in.
NAS: Don't Call It Backup (Most of the Time)

Another prime feature of NAS drives—redundancy between drives, for an element of data protection—is an option on models that have more than one drive or drive bay inside. Every NAS drive we’ve tested with more than one drive bay gives you the option of putting the drives into a mirrored RAID array, so that everything written to the first drive gets copied to the second, as well. (RAID stands for "Redundant Array of Independent Disks.") An alternative to that is striping, a speed-up technique that spreads your data across multiple physical drives to make data access faster (because the NAS can spin up multiple drives at one time). Striping by itself isn't secure, though; if one drive in the striped set fails, you can lose access to all your data.

With that in mind, more complex arrangements than mirroring and striping are possible with NAS drives with more bays; in some, data can be striped or spread across two or more drives with just enough redundancy among them to allow for restoration of the whole data set if one drive fails (also called "striping plus mirroring"). If there’s ever a failure under a mirrored scheme, it’s not noticeable except to the NAS administrator, who will get pinged; the unit just switches to the backup drive or drives seamlessly.



A Mac-minded, one-drive NAS: Promise Technology's Apollo

The only downside to a purely mirrored setup is the cost, as it requires two identical-capacity drives to make the redundancy possible. So, for example, two 4TB hard drives in a mirrored arrangement yield just 4TB of effective, usable capacity. But this kind of arrangement provides what is called in enterprise scenarios "fault tolerance"—insurance against one of the drives physically failing and taking your data down with it.

Don't confuse this, though, with truly bulletproof backup. To be sure, you can use a NAS drive as backup, copying data that lives locally on your networked PCs in duplicate on the NAS, either automatically or manually. This creates a backup copy in the event your system drive dies or gets corrupted—a good idea. But real backup proofs your data against localized events that can take out your whole data store in one shot: a fire, a break-in, a massive power surge, a flood. All of these can wipe out your primary data and your backup if your NAS and your system are near each other and both suffer the same fate. To prevent this, some NAS units provide a way for you to back them up to another, offsite NAS. (We know, this is getting complicated.)

The short version: Backing up to a NAS is good practice—and plenty of NAS drives come with good backup software or make such apps available. But don't confuse it with a foolproof data-protection plan if all your data physically resides in close proximity.
NAS Drives: The Buying Basics



The bottom line is, if you’re in a home or office where multiple people need to share files, or you’re looking for a simple way to back up important data, a NAS device is the easiest way to do it, unless the amount of data is small enough to make stowing it in the cloud feasible. And like any computer peripheral, the features offered by the various NAS units vary greatly to meet the demands of different households, offices, and environments. So you’ll need to understand the terms and features before you go shopping.