A Closer Look
Taking a look at the Sentinel DX4000, we have a 4-bay NAS with a mostly metal chassis. The configuration we were given comes with four 3TB Western Digital enterprise drives making for 9TB of effective storage space when configured in RAID 5.
One interesting feature is the redundant power supply of Sentinel. You don’t typically see that in consumer grade NAS’s. This just shows that Western Digital is packing some enterprise grade bells and whistles in their small office appliance. Purchasing an additional power brick to enable redundant power will set you back $60. Also included on the back of the NAS are 2 USB 3.0 ports and dual gigabit NIC’s to help in your high speed data transfers.
The LCD screen on the front of the device shows important information for the system such as the IP address, disk space free and diagnostic information if there is a problem. One thing I would have liked to see displayed was CPU utilization, but it isn’t a deal breaker that it’s not there.
One minor annoyance that I noticed is that even when the unit is powered off, the fan still runs at full power. Western Digital has commented in their forums about this, saying that it is done by design.
Supported RAID Levels
The RAID level that the Sentinel is configured in is entirely dependent on how many drives are in the device. The end user is unable to configure the RAID level. You are stuck with RAID 1 for 2 drives and RAID 5 for anything over 2 drives. This helps simplify things for business owners who may not be the most tech savvy and not know what various RAID levels are or how they perform. On the other hand, this does take away control from power users and experts who enjoy tinkering with RAID volumes.
One decision that Western Digital has made for this product that is bound to upset the more tech savvy, is the limitation of what drives can be used in the device. Western Digital has a list of approved drives here. This means that not even all of Western Digital’s drives will work with the device, only specific ones on the list. I can see why they’re taking this approach. It’s very similar to what Apple has done for their line of products, by controlling the part supply you can control the quality of the product. Western Digital is marketing the Sentinel as pretty much a plug in appliance for small businesses. In this particular scenario, it’s not a strike against them for limiting the supply line for replacement drives.
Under The Hood
Disassembling the DX4000 is a fairly straight forward process. There are 5 screws on the back that you have to remove to take off the outer casing.
Once the outer casing is off, you can see the motherboard of the unit. We will get to checking out the motherboard soon, but first we remove it by taking care of the attached ribbon cable for the front display and the 6 screws that hold the board to the case.
With the motherboard removed, we see the top spring mechanism of the drive bays along with the PCIE connector that attaches the drive backplane to the the motherboard.
The motherboard has a single PCIE slot that it uses to connect to the drives. The CPU as well as the Southbridge are passively cooled on the board.
We can see that the mobo only has a single RAM slot. It is populated with a 2GB stick of hynix DDR3 RAM. Due to a lack of spare parts on hand, we are unsure if you can just drop in a larger capacity RAM stick as an upgrade or if it is somehow locked like the types of hard drives you can use.