A Faster NAS Alternative

By Joseph Moran | Posted June 29, 2006

When a PC runs low on storage, a quick and easy way to add more is to use an external hard disk with a USB or Firewire interface. But while this works great for stand-alone systems, it's not the best choice for a small business with multiple computers that need to access the storage.

When companies need shared storage, they often use a Network Attached Storage (NAS) device, which connects to the network instead of just a single PC. But Ximeta is offering people who need networked storage an option other than NAS with its NetDisk product, which uses technology the company terms NDAS (for Network Direct Attached Storage). Ximeta says NDAS makes the NetDisk easier to set up than NAS products, and provides better performance to boot.

The NDAS-based NetDisk has two major differences compared to NAS. Although the NetDisk connects directly to a network switch just like a NAS device it forgoes TCP/IP in favor if its own proprietary protocol, so it doesn't require any TCP/IP configuration. (By contrast, most NAS devices contain an internal server that emulates a Windows server and must be assigned either a static or dynamic IP address before it can communicate on the network.)

When accessed from a PC, the NetDisk looks and acts as if it was an internal or directly connected external drive. NAS devices share their storage via TCP/IP, and although you can use network mapping to assign drive letters to NAS-based drives, they're still treated as remote drives by the computer.

Screen shot of NetDisk as it appears in Windows' My Computer
Unlike NAS devices, the Ximeta NetDisk looks, acts and performs more like a direct-attached drive.
(Click for larger image)
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We found that Ximeta's NetDisk is superior to NAS devices in some respects, but it also has a few serious limitations.

Installation
The NetDisk — compatible with Windows 2000, XP, 2003 Server and Mac OS X, but no Linux — is available in capacities ranging from 80GB to 500GB. We looked at a 400GB model with an MSRP of $399.99. At a glance, the NetDisk looks like a garden-variety external hard disk. In fact, since it has a USB port you have the option of using it with a stand-alone PC, and if you choose to use it that way it doesn't need any special drivers or other software.

In a networked environment, however, each PC that needs to access the NetDisk must have client software installed. Since the NetDisk uses the regular Windows file system (NTFS), if you first set up the NetDisk on a network and subsequently connect to it via USB, all the data is still accessible. (You can't, however, use both the Ethernet and USB interfaces simultaneously.)

After you physically connect the NetDisk to power and the LAN, you must run the NetDisk software on a PC to "register" the device to that system. Registration involves entering a 20-digit alphanumeric key that's found on the underside of the NetDisk, and entering this key enables read-only access to the device — if you also want write access, a separate five-digit key must be entered as well. The registration process must be repeated on every system that will access the NetDisk, though you can streamline the process a bit by exporting the keys to a file, which saves you the trouble of having to type them in again at each new system.

Using the NetDisk
After you complete the NetDisk registration on a particular PC, you have to mount the drive using a utility that automatically appears in the Windows Tray.

When using the NetDisk it's easy to forget you're working on a networked drive. The drive's response time is almost instantaneous, with none of the lag you often get when working with a network folder. Another plus is that when you delete a file from the NetDisk it goes into your Recycle Bin, which doesn't happen on a conventional networked drive like NAS.

There are times, however, when you need to remember (or are reminded) that the NetDisk is in fact a networked drive. For example, having a NetDisk mounted will prevent your PC from going into standby or suspend mode — you can override this behavior, but it's not recommended since it can lead to data corruption.

Similarly, Windows will let you run potentially destructive disk operations like error checking, format or partition on the NetDisk, which is fine if you're the only one connected to it. (Remember that as far as Windows is concerned, NetDisk looks like it's directly attached to your system.) But those operations can scramble your data if you have multiple people accessing NetDisk.

Security
The NetDisk does provide at least one notable security advantage over NAS. Since the NetDisk isn't accessible via TCP/IP, it's not vulnerable to attack or unauthorized access from the Internet or even from systems on the local network. Having said that, the NetDisk (or NAS devices for that matter) are still susceptible to attacks — such as a virus or other malware — that originate on any system that connects to it.

For the most part though, when it comes to security the NetDisk isn't as capable as most NAS products. For example, unlike NAS, NetDisk's NDAS technology won't let you define user accounts or control access to individual folders — a significant limitation.

This means that any PC with both the NetDisk software (which is freely available for download at Ximeta's Web site) and the registration key(s) can obtain full access to the entire device (which includes multiple users of the same PC). Keeping the NetDisk in a locked room can be an effective way of keeping the keys secure since you can't glean them from an already registered system (they don't display the entire key).

But there's another possible security issue to consider when using the NetDisk. Although direct access to the unit requires the software and key, there's nothing to stop someone who is on a registered system from making the NetDisk available via conventional Windows file sharing. Although you can do this on purpose to get around the need to install the client on every system, doing so effectively negates any security benefit of not using TCP/IP in the first place.

Performance
Ximeta boasts that the NetDisk is significantly faster than a NAS device (in part due to the elimination of Windows' TCP/IP file-sharing overhead), and we found those claims to be justified when comparing the NetDisk to a Maxtor 300GB Shared Storage Drive.

To gauge both read and write performance, we copied a large (1.2 GB) file from a system with a wired LAN connection to and from each device. Copying the file to the NetDisk took an average of 1:55 (minutes:seconds), while copying the file from the NetDisk back to the system took almost exactly the same amount of time at 1:56.

In comparison, copying the same test file to the Maxtor drive took almost twice as long (3:55) and copying the file from the Maxtor drive (2:45) still took almost a minute longer than from the NetDisk. Both the NetDisk and Maxtor have internal drives with the same 7,200 RPM rotational speed, though the Maxtor's 16MB of cache is actually twice that of the NetDisk.

Many NAS devices have only one disk drive and don't let you add additional capacity, but some do contain (or allow for) more than one drive, which in addition to providing added storage also lets you set up RAID for improved performance and/or data redundancy.

We didn't try it (since we only had one unit), but Ximeta lets you expand your NetDisk by connecting additional units to the network and then using a utility to bind them together into a single logical disk, a stripe set (RAID 0) or a mirrored pair (RAID1). Although you can string up to eight NetDisks together, RAID 5 (striping with parity) is not available so using more than two limits requires you to forgo any fault-tolerance.

Conclusion
Based on our online research, a NetDisk will cost roughly the same as a single-disk NAS drive of the same capacity. So with pricing being about equal (up to a point, since multiple NetDisks will very likely be more expensive than one large-capacity NAS), is the Ximeta NetDisk a viable alternative to NAS?

It can be, but only under certain circumstances. If you have a relatively small number of users, performance is your paramount concern or you work predominantly with large files and streaming media, then the NetDisk could be a good choice. (This is particularly true if you need to stream content to a set-top box or similar consumer-electronics device, since many don't interact well with network drives.)

On the other hand, if security is important enough that you need to store sensitive data and limit access to particular employees, NAS is the better way to go.

Price: $399.99 (MSRP, 400 GB model)
Pros: Better performance than NAS; scalable storage
Cons: Limited security; no Linux support

Joe Moran spent six years as an editor and analyst with Ziff-Davis Publishing and several more as a freelance product reviewer. He's also worked in technology public relations and as a corporate IT manager, and he's currently principal of Neighborhood Techs, a technology service firm in Naples, Fla. He holds several industry certifications, including Microsoft Certified Systems Engineer (MCSE) and Cisco Certified Network Associate (CCNA).

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