NAS, SAN, DAS...Huh?

In the land of storage, acronyms get tossed around like fruitcakes in December, and it's easy to confuse the flavors that exist. IN addition to NAS, there's also SAN (storage area network) and DAS (direct-attached storage). While they all share a similar functionality--they exist to provide some form of file storage--they do differ.

Network-attached storage refers to single hard disk-based devices that connect to a network over Ethernet or TCP/IP, and use file-sharing protocols that allow computers to access their disks as remote volumes. A storage area network is used more in enterprise-level businesses, and consists of a network of Fibre Channel-connected storage devices (usually multiple disk arrays) that communicate with servers as large-scale local disks. Direct-attached storage is exactly that--storage that's directly connected to a computer or server, such as a RAID array, external hard drive, thumb drive, or optical drive--no network required (no network sharing either).

NAS is the best choice for SOHO users; you get file-based shared storage that's easier to set up, troubleshoot, and access across a mixed computer network. With its expense and complexity, SAN is for enterprise businesses; you get speedy data transfer (Fibre Channel is almost three times faster than SCSI) and better data redundancy, but instead of file-based storage, the data is delivered and stored as disk blocks, and set-up generally requires highly technical expertise and skills. If you're not into sharing, DAS is the easy choice--and the one you're probably already using.

NAS Shopping tips

Mac Compatibility Not all NAS drives play nice with Macs. In the NAS world, SMB (Server Message Block), a Windows file-sharing protocol, rules. Macs can use it, but due to some file-naming restrictions, you may have to rename some files. Macs use AFP (Apple Filing Protocol) for file sharing, so look for NAS drives that support it--some support Bonjour (OS X's built-in networking protocol for local network devices), too. For configuring ease, most NAS drives come with software or a Web browser-based wizard that'll walk you through the process, but some setups can be tricky--especially if the device doesn't support AFP.