Insider Details: ASUSTOR AS-604T NAS Server
The insides of these things are always more interesting than the outsides, at least to me. The AS-640T comes apart very quickly and easily, with about three screws that need to be removed on the rear panel. Once they’re out, the outer shell slides a bit to the rear and then lifts off, revealing all the internal parts. Further disassembly requires a few more screws, including one covered by the obligatory “Voids The Warranty” warning label. Fortunately, this screw doesn’t need to be removed in order to access the additional SO-DIMM slot, where you can add a few extra Gigabytes of DRAM to the AS-604T. Once these half dozen screws are removed, the rear panel comes off with the fan attached to it, and the tear down can begin in earnest. The main controller board takes up the entire left side of the unit, and nearly everything is integrated on the one board, including all the back panel connectors. The exceptions are the backplane where all the SATA connections for the drives are located, and the LED display and menu buttons from the front panel, which connect via ribbon cable and a small card-edge connector. The main controller PC board attaches to the inner chassis with four screw and threaded standoffs.
Once you remove those couple of screws holding the rest of the chassis together, it comes apart in several smaller pieces. Most of the inner framework is permanently fastened together or formed from a single sheet, so there are very few loose components that form the actual chassis, and it stays dimensionally stable. The backplane is held securely in place, at seven different locations. Six of those are grooved pins and keyhole slots, and one has a machine screw in that location. The result is a very stiff backplane, which is exactly what you want for a component that has 1 kg HDDs occasionally slamming into it. The 250W integral power supply sits on top of the drive bays and is held in place with two screws on the rear panel and two more inside the chassis. The electrical output looks very close to a standard ATX motherboard supply, and you can see where the pigtails from the PSU are connected to the main controller board along its top edge.
The main controller board is densely populated, but not as much as a high performance video card. The main PCB and backplane connect with an x4 PCI Express connector located toward the rear of the controller card, between the CPU and the stacked I/O connectors at the very rear of the unit. All the electrical current comes through the main controller PCB. With all the current that needs to go out to the hard drives, a four-bay unit like the AS-604T is probably the limit for this type of power distribution scheme. I suspect the AS-606T, with six HDDs to feed, has SATA power connections landed directly on the backplane PCB. The two passively cooled heatsinks cover the main chips supplied by Intel, the Dual-Core D2700 Atom CPU, and the ICH10R Southbridge that provides the PCI Express lanes, the eSATA connections, and the RAID logic. These two ICs do the bulk of the work for this NAS device; the only other chips that are even moderately stressed are the memory and the Ethernet controllers. The larger heatsink is on the ICH10R, which was not designed specifically for low power applications like the Atom CPU was, and actually does a lot of the heavy lifting in this application.
The drive bay is one large space, with grooves formed into the sheet metal chassis to provide four separate slots for the drive trays to slide into. There are plenty of ventilation cutouts in the chassis and the backplane to allow air to make its way towards the one large 120mm fan on the back panel. The open area on the left inner panel is where the air from the holes on the outside cover eventually flows, after passing over the main PCB and the two heatsinks there, sitting on top of the CPU and Southbridge.
The drive bays are not marked on the front bezel, and the individual drive trays are not marked. With the unit safely turned off, it’s OK to remove one or more drives and after they slide out the front, they look like this. Each steel-framed tray holds one individual drive, and the tray is a common part across several models in the ASUSTOR product line. Since the trays are not labeled with the chassis slot number, you can mix and match them all you want, until you build a drive array and then you had better remember which one goes where. I recommend making your own labels or marking the trays with a Sharpie as soon as you start installing drives into the unit; if you mix them up the NAS won’t recognize the array, and worst case you could end up destroying data as you try to figure out which drive is which. Inserting and removing the drive trays was smooth and positive, both with HDDs mounted in the trays and without. The latches acted like a locking lever; once the trays reached the end of their travel, swinging the latch down levers the tray firmly into place.
In case you want to add DRAM to the ASUSTOR AS-604t, it’s a relatively easy proposition. Remove the outer cover, which is just three screws worth of effort. Then peel back the protective plastic cover on the left side of the chassis, and the empty, spare DIMM slot is exposed and easily accessed. The standard memory is sitting in a similar slot on the other side of the board, and is not accessible without further disassembly, which will void the warranty. There’s 1 GB of DDR3-1333 installed on the interior DIMM slot, and the outer slot is intended to accept a 2GB upgrade, although a 1GB SO-DIMM would probably work. If you need a memory upgrade, you are going to want to go for as much as you can install, and the ATOM CPU can only address 4GB. Many applications won’t really benefit from more memory, so be sure it will benefit your purpose before going to the trouble of upgrading. Hint: basic file transfer operations don’t need any extra RAM to improve their function.
So far we’ve had a good look at what there is to observe as far as hardware goes, but let’s dig down one more layer, down to the chip level where the technology really starts to get interesting. I love my shiny hardware just as much as the next person, but it’s only part of the story….