Count me as a fan of network-attached storage (NAS) technology. I especially like the desktop appliances, which are not much bigger than a four-slice toaster on the outside, but with huge space on the inside.
The appliances are the workgroup NAS units, and today’s models hold from 1 terabyte to 10TB of storage. The rack-mounted NAS units made for enterprise storage can hold from 1TB up to 24TB of disk space.
Workgroup NAS appliances come with one to five disks, and they share storage for a relatively small (2 to 50) group of users. Small companies often use these as shared storage before they get a small business server. Departments in large companies also utilize these, particularly if their IT department doesn't respond to requests for extra storage space.
But what makes a NAS a NAS ? It’s attached to the network, not a particular computer or server, and has an operating system that allows users to have private disk space and share public space. Someone must set up the user database, but those are simple chores. Each user has a private area and access to a public area. Shared storage means having a single place to put important shared documents, and it ends the hunt for an important file across multiple PCs.
A NAS appliance can have a single disk drive, but avoid those units. When you have shared storage, reliability is critical. A single-drive NAS unit may never falter, but if it does, your files are toast. One good reason for a workgroup NAS is to back up files from individual computers, so at least two disk drives are needed, mirrored, for data safety. If one drive dies, you won't lose your data.
Large companies often appreciate units with four or more drives, configured with RAID-5 (Redundant Array of Independent Disks, level 5), which spreads files across all disks for better speed and redundancy. If one of the drives dies, files are still usable. These units tend to have more complex operating systems, and support more users as well.
As hard-disk prices drop and capacities jump, the value of external storage gets better every day. Want 4TB? (That’s about 2.75TB of usable space on a RAID-5 system.) There are multiple options for less than $1,000. The two-drive versions are even less: A unit with mirrored 2TB drives (with effective capacity of 2TB) can be had for well under $500.
Two models, the Iomega StorCenter  and Buffalo TeraStation , include file indexing and searching software. This provides a rudimentary document management platform for free. Let’s hope others also include indexing and searching software in the future, because Google has convinced everyone to search for, not logically file, documents.
Those interested in virtual servers will be pleased to know that most of the workgroup NAS units and all the larger enterprise units can serve as shared storage for virtual machine images. Because all workgroup NAS devices run some type of highly customized Linux operating system, they can support PC, Linux and Macintosh clients at the same time, reading and writing the same files.
Besides Iomega and Buffalo (who was the first to break the 1TB-for-$1,000 barrier with their TeraStation several years ago), check out Seagate BlackArmor, Netgear ReadyNAS and LaCie units. All have various models and capacities, and all work quite well.
As your company grows, make sure your workgroup NAS keeps up. If you add a Windows server, you can integrate the NAS storage into your Active Directory structure. Some units allow access to files over the Internet, and some units replicate files between remote units for disaster recovery — pretty clever for an inexpensive little box that sits quietly on a shelf.