Product Reviews

Just when you thought the network storage industry couldn't come up with another acronym, along comes Ximeta with NDAS (network direct attached storage). This sounds like a contradiction in terms, but the idea behind NDAS is that unlike NAS the storage appliance doesn't require a connection over TCP/IP and appears to each client system as a local hard disk, rather than a shared resource that needs to be mapped to a drive letter. Obviously, a protocol is needed for a network connection and this is handled by Ximeta's own LPX (Lean Packet eXchange).

Ximeta offers a range of NetDisk products, and the Office version here combines a 250GB hard disk with an eight-port Ethernet switch and a USB 2 port for local connections. Installation is simple enough, but NDAS mode requires an administration utility to be loaded on each workstation. These are provided for Windows and Mac OS X, but in non-XP or mixed environments simultaneous read-access is granted, while exclusive write-access must be passed from one system to another. This is the biggest drawback of the NetDisk, as this isn't an automatic process. If your network has any Windows 98 SE, ME or Macintosh systems, only one user can have write-access and must manually relinquish it using the administrator utility before another user can request it. Only in Windows 2000 and XP environments

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is simultaneous write-access supported.

Manually loading the client on each system is a nuisance, but security is one advantage of NDAS mode as the appliance is inaccessible to other users on the same network that don't have the software installed. Furthermore, the administration utility requires each NetDisk to be registered with the client using the ID code on the base of the unit, and even write access can be granted only if a second key is entered. If you have multiple NetDisks you can also aggregate them together for one large disk or mirror them for improved data security.

We tested using Windows XP workstations, and when the codes had been entered the NetDisk was immediately identified as new hardware. Sure enough, once the drivers had been loaded, Device Manager showed a new NetDisk SCSI controller and hard disk had been added, while Explorer revealed a new local drive already preformatted as NTFS and ready for use. You'll also find the LPX protocol support has been installed. In USB mode, all you need to do is connect the device and load the supplied driver, but note that Ethernet connections can't be used concurrently.

Raw performance over a Fast Ethernet network isn't impressive, as the open-source Iometer utility reported a modest 15.6Mb/sec for one client and a cumulative total of 12Mb/sec for two. Copying a single 1,061MB disk image file from one client to the NetDisk returned an average of 14.5Mb/sec. For general file sharing the NetDisk worked well enough, and we had no problems writing data simultaneously from two XP clients to the appliance.

Performance isn't great but the price and security features available in NDAS mode gives it an edge over standard NAS appliances in a small office environment. There's no denying the NetDisk Office is a unique form of network storage, but even so, we'd suggest you use it only for networks exclusively made up of Windows 2000 and XP clients.