NAS devices comprise basic server hardware and storage components. Essentially, they're servers with a ton of storage. The secret sauce that turns these devices into turnkey appliances is specialized NAS operating systems. Some machines run the Microsoft SAK (Server Appliance Kit), a stripped-down version of Windows 2000 Server for use on NAS devices. With SAK, the NAS device can natively run some Windows software, such as backup agents. SAK also saves you the cost of a full-blown Windows server license for your NAS box. Many other NAS machines run a Unix variant, such as Linux or FreeBSD. Other companies have hand-coded their own tight kernels, which may seem impressive but often offer few advantages.
NAS Device Performance
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To test midrange NAS devices, we invited 20 vendors to send us systems priced from $5,000 to $30,000. We asked for at least one copper Gigabit Ethernet port and recommended that vendors send 1 TB of storage with enough spindles to ensure maximum performance.
We received machines from Dell, Excel Meridian Data, First Intelligent Array (FIA), Hewlett-Packard Co. and Procom Technology. Advanced Media Services, Auspex Systems, BlueArc Corp., Delta Networks, EMC Corp., Gateway, Hitachi, IBM, JES Hardware Solutions, Network Appliance, Network Storage Solutions, RaidZone, Rare Systems, Snap Appliance and Sun Microsystems received invitations but declined to take part in our tests.
The participants all complied with the 1-TB minimum and included two or more copper Ethernet NICs. Prices ranged from $14,745 (for Excel Meridian's NetStor MVD) to $29,995 (Procom's NetForce 1800). Beyond the basics, however, we got quite a mix of hardware and physical configurations: internal disks, external disks, SCSI connect, Fibre Channel connect, and a multitude of Ethernet connections of varying speed and type.