Most external hard drives connect directly to your computer with a USB, FireWire, eSATA or Thunderbolt connection. Experts call these types of external hard drives direct-attached storage. If you run a home network or business network, you might consider a network-attached storage (NAS) drive instead. NAS drives connect to your network with a gigabit Ethernet cable. Most NAS devices essentially act as servers, where users do such things as performing backups, file-sharing and streaming content. NAS devices can come as complete standalone units or enclosures with no hard drives included. Although the drive is then accessible to all devices on the network, data speeds are limited to the speed of your network, which is likely to be significantly slower than USB or FireWire -- and much slower than eSATA or Thunderbolt.
You can buy NAS boxes with no hard drives included -- just empty slots where you insert your own hard drives. Computer-savvy users often say that these work better than cheaper plug-and-play NAS drives because you can choose exactly the drives and sizes you want and replace the drives if they break.
Among these types of network external hard drives, the Synology DiskStation DS412+ (Est. $650) NAS receives much acclaim from reviewers. CNET awards this Synology NAS an Editors' Choice and 4.5 stars out of 5. Reviewer Dong Ngo says it "makes an excellent NAS server for advanced home or small-office networks," and he is impressed with its performance, array of features and user interface. It can host up to four drives, which makes it ideal for large-scale backups. Experts agree that the user interface is robust, but that it might be a bit complex for the not-so tech-savvy. The Synology DiskStation DS412+ receives much praise from owners on Amazon.com as well, and negative reviews there are rare.
For those with tighter budgets, there are cheaper Synology NAS models for basic home use, such as the Synology DiskStation DS213Air (Est. $300) which receives solid reviews from CNET for its "fast data performance," array of features and built-in Wi-Fi. Lenovo's Iomega StorCenter ix2-dl (Est. $300 for 2 TB / 1 TB Dual) NAS also gets decent reviews. It's "a very good NAS option that can work for power home users or small business," writes Samara Lynn at PCMag.com. It receives an Editors' Choice at Laptop Magazine, where Joel Brandon praises its "super-fast" transfers and "versatile storage" but says cloud setup is difficult.
For basic home users, a professional-grade NAS drive is probably overkill. For those, a few external hard drives can create NAS-like experiences and cost much less.
The Seagate Wireless Plus (Est. $200 for 1 TB) external hard drive allows you to access data from the drive wirelessly. It includes an internal Wi-Fi radio that can communicate with your smartphones, laptops and tablets. This lets you access and stream music, videos and photos wirelessly.
Joel Santo Domingo at PCMag.com calls the Seagate Wireless Plus a "controllable alternative to hotel in-room movies," considering that it relies on a Wi-Fi hotspot rather than 3G/4G Internet. It supports up to eight devices at once. It's battery powered, which means you can take it on road trips. Santo Domingo reports battery life lasting 10 hours for one user streaming SD video; battery life will vary by usage. WPA security must be setup to prevent others from accessing your files.
The Seagate Wireless Plus gets Editors' Choice nods at PCMag.com and Laptop Magazine. The Wireless Plus is preformatted for Windows (NTFS) -- "and it must remain that way to work," writes Michael Calore at Wired.com. Calore says Mac users will need a "special utility to write to it," which requires some technical know-how. Santo Domingo makes this seem less difficult, saying you can download the Mac utility from Seagate's website. The USB 3.0 interface offers decent though not class-leading data transfer times, but moving a big library of files via USB 2.0 can be an all-day affair, PCMag.com says.
The Pogoplug Series 4 (Est. $30) is arguably the easiest, and cheapest, way for home users to get the benefits of a network backup external hard drive. It's a little gadget that turns your external hard drive, flash drive or SD card into a basic NAS (accessible over the Internet, however, rather than directly through your network). You don't need any software or special skills -- just plug this compact little box into your Internet router, and you'll be able to access all of your data over the web, from anywhere. Apps are available that let you access or upload content to and from smartphones and tablets.
Experts say the Pogoplug Series 4 is very simple to use. PCMag.com awards it an Editors' Choice and says it's a safer way of simulating NAS than storing data on a cloud service, which subjects your data to forces beyond your control. Reviewers agree, however, that the device has some issues with video playback. Scott Stein at CNET notes that the Pogoplug Series 4 starts to run hot after a while.