The Large Office
For a large office or for multiple small offices, NAS performs well in its fundamental role as a workgroup storage and backup device. Instead of creating a large single node in a server room at the end of a network or broadband pipe, you institute local storage or backup via NAS.
NAS is also ideal for sharing printers via the USB ports that nearly every box has. Some NAS boxes integrate additional peripherals that may be shared over the Internet via the Internet Small Computer System Interface (iSCSI), an IP-based protocol for data transfer. One such NAS product is the LG N2B1DD1, with its Blu-ray writer.
NAS boxes from Synology, QNAP, and others slide seamlessly into your domain, automatically grabbing users from Active Directory and similar technologies for quick setup. Online Amazon S3 backup is now featured on boxes such as the QNAP TS-259 Pro, so you may easily set up off-site backup on top of local backup of the NAS box, to USB drives or across the network.
Part of the appeal of NAS is its simplicity, but serving applications from a NAS box is no walk in the park. It is doable, however, depending on the type of access the box provides. Obviously, to run a Windows app, you'll need a Windows Home Server box, such as the HP MediaSmart EX495. For a Linux app, use a Linux-based box that allows low-level access. For most users, WHS is far easier to set up in the application-serving role, as it introduces the full Windows desktop that people are accustomed to working with when they access the box via Remote Desktop. Beyond that, be prepared for some heavy tweaking.
Hollywood's Got Nothin' on Me
Nearly all NAS boxes are Universal Plug and Play (UPnP) enabled, and many are Digital Living Network Alliance (DLNA) certified for serving images, music, and video across local-area and wide-area networks. The latest Windows Media Player will detect and stream media from any DLNA or UPnP-capable NAS box on the local network.
The majority of NAS boxes can also serve to iTunes. This is great for a home entertainment network, and it has numerous applications in the office for background music, running infomercials on a TV, making in-house presentations, and so forth.
Some NAS boxes can stream music, video, and images through your Web browser, without any need for additional software. If you are off-site at a meeting and want to show photos of a new plant that a colleague just took and uploaded from the construction site, you can: Just fire up your laptop, browse to the NAS box slideshow application (usually located on a dedicated port at the base address, such as mycompany.dydndns.org:7002), browse to the correct folder, and you're viewing. The Synology Disk Station DS209+ is a good option for media streaming purposes.
Now that your curiosity is piqued, what should you buy? We've covered most NAS software features, so I'll stick with the basics: redundancy, capacity, and speed.
Don't buy a single-drive NAS box for your business. For a home network that does nothing but stream music and movies, a single-drive model is fine, but a business needs at least a two-drive box for mirroring one drive on the other (RAID 1). This arrangement permits continued access when one drive fails. Notice that I said "when", not "if." Drive failure may be years away, but it will eventually happen.
NAS capacity is simply the size of the drives multiplied by the number of drives on board (normally between two and five), divided by the RAID mode in use. Single-drive capacity currently tops out at 2TB, so you're talking about up to 10TB of storage in a high-end SOHO unit.
Speed comes courtesy of the drives, the CPU speed, and the ethernet connection. Faster drives are better, higher CPU frequencies are better, and nearly all boxes now offer speedy gigabit ethernet.
Better boxes also offer multiple ethernet connections. In some cases, this is simply for failover--the option, assuming different network paths, for a backup connection to carry on if the primary one fails--via Multiple Path I/O, or MPIO.
More-advanced boxes, such as the QNAP TS-259+ Pro mentioned earlier, achieve increased speed via Multiple Connections per Session (MC/S), where both connections are used for data transfer. Keep in mind that the speed and traffic on your local network may be limiting factors, so don't overbuy when it comes to hardware.