On the surface, the fact that the WD Sentinel DX4000 is powered by Windows Storage Server 2008 R2 Essentials and two NICs intimates that it should be a highly flexible and capable NAS. However, as shipped by Western Digital, a number of limitations rapidly appear. Being the stubborn type, I decided to see how many of WD’s limitations could be overcome to make my large investment in the 12 TB device seem wiser than it initially appeared.

First, here are the significant limitations I encountered after setting up the DX4000 on my network:

1. The two NICs are configured in failover mode only, and teamed, meaning two active network connections cannot be established. This is a significant limitation if trying to use the DX4000 as a low-cost centralized storage server for Hyper-V and/or VMware.
2. Given that the DX4000 ships with WSS 2008 R2 Essentials, iSCSI support otherwise available from Microsoft in non-Essentials versions of WSS, is not provided. This significantly limits the ability of the DX4000 to act as a centralized storage server for Hyper-V and/or VMware. Although theorectically the DX4000 supports NFS, which would allow one method of leveraging the DX4000 in an ESXi environment, out-of-the-box WD documentation and tools do not indicate in any way whatsoever how to install support for and configure NFS, and it does NOT ship with NFS support already configured.
3. Although capable of supporting two power sources, the DX4000 only ships with one laptop-style power brick. However, additional DX4000-compatible power bricks are available for about $65 (including shipping and handling).
4. The DX4000 ships with only 2 GB of RAM installed, which imposes a perceptible limitation on throughput speed. Despite the low cost of RAM today, Western Digital does not provide an officially sanctioned, or described, method of installing additional RAM.

Fortunately, workarounds exist to overcome all of the limitations listed above. In subsequent posts, I will describe how I overcame each limitation. However, doing so essentially obliterates any hope of securing warranty support for your unit. So if you choose to use my approach to making the DX4000 a much more capable NAS, be aware that you will now be solely responsible for fixing and/or repairing any issues you may encounter down the road.

As an aside, I have built and use a four-bay Thecus N4100PRO NAS running a variant of Linux. Although the unit has been reliable and can theoretically be configured to provide a number of additional services over and above centralized storage, and provides support for iSCSI, for predominantly Windows-centric IT environments, the WD Sentinel DX4000 offers a number of attractive features with regard to integrated managability in a Windows network environment. I have also worked with another mainstream WSS2008R2-powered NAS device, one provided by Buffalo Technologies (the Terastation Pro series). The Buffalo units do not ship with the same number of limitations; however, when I last used and configured two Terastation Pro units, I found they relied upon Windows for RAID support, whereas the DX4000 leverages Intel motherboard-based hardware RAID. For this reason alone, I was willing to invest in a WD Sentinel DX4000.