Buying Guide: Network-Attached Storage

Small business that have mission-critical data or home users who download a lot of MP3 files, shoot and save digital photos, or edit videos need to understand what a network-attached storage (NAS) device is. Eventually, anyone who keeps a large amount of important data starts thinking about repositories less vulnerable than PC hard drives, and that means something external. Often the best, most cost-effective solution is a NAS. So what is it, why do you need one, and how do you buy and use it?
A NAS isn't simply an external hard drive. It's a computer, with an OS and one or more hard drives, that's dedicated to storage tasks and can connect to a network. Most communicate over wired Ethernet, but some, such as the Iomega StorCenter, can do so wirelessly. The OS, generally just a Linux or Windows kernel, handles volume and drive management, networking, security, and user access. It often has extended features, such as backup capability. The functions are usually managed through a Web-based graphical user interface.

For a small business, centralizing data on a NAS is a good management practice. If information isn't dispersed on separate PCs, accessing it is simpler, as is managing security. And when storage needs increase for one or more employees, maintaining a single device is far easier than adding and managing locally attached external drives, putting a new server online, or installing drives in existing servers. In addition, prices have dropped: A 1TB NAS costs well below $1,000.
Selecting a NAS for your home or small business isn't rocket science, but there are a few important basics to keep in mind. Stay away from single-drive solutions—especially for business applications. If your one-drive device's drive dies, not only do you lose all your data, but employees who depend on it are sidelined. You want something that supports at least two drives in a configuration called RAID 1, which mirrors data—keeps the same information on different drives to preserve it if one crashes. Also, check that you can easily remove the drives from the front or back—the best cases have slide-out trays and allow for a tool-less exchange of drives.

If multiple users share data, make sure the NAS has share-level and user-level security and lets you assign users read-only access, not just full privileges and none. For organizations with more than ten users, look for a system that lets you change permissions for groups, so you can easily make changes for multiple users. A NAS with good access-rights management can be a good alternative to a file server in the home and in a small business. It can also be useful for a home office that shares space with home users. If you have remote offices or several small workgroups, you want an appliance that can double as print and FTP (File Transfer Protocol) servers. Many devices in this guide can.

After these considerations, for entry-level ­devices, choose based on price, capacity, and physical size, not performance (it's not significantly different among products at this level). The Linksys EtherFast Network Attached Storage EFG250, for example, offers a good combination of the three. Buffalo and Infrant Technologies make units with greater capacity and even more features.

Businesses that have 25 to 100 employees or bigger storage needs will find several boxes in the $2,500 to $5,000 range that offer robust data protection, flexible RAID options, and more advanced backup and restore capabilities. Some good examples are the Adaptec Snap Server 4200 and the Aberdeen AberNAS 211, which hold up to eight drives and let you replace failed drives in RAID configurations on the fly. The units are rack-mountable and rugged, and they include server-class processors and more memory. They also provide detailed logging and reporting tools, as well as anti­virus and versioning software and flexible backup. Many of these products handle online archiving and backup of content stored on file servers.