Internal Details: QNAP TS-870U-RP Turbo NAS
The top cover is easily removed once two thumb screws on the back panel are taken care of. The modular layout is quite evident; the main board takes up a large part of the total footprint. The drive bays at the front of the unit use almost the same amount of space, just more rectangular, and the power supply area is a smaller, but still significant part of the overall arrangement. The cooling fans are mounted on a removable aluminum plate that forms the border between the drive bays and the rest of the unit. Some things to look for, that we’ll see in more detail as we continue the tear down, are: the four memory slots, the two x8 PCI Express slots, the DOM memory board, and the two heatsinks showing the locations of the Sandy Bridge CPU and PCH (Platform Controller Hub, nee Southbridge).
The QNAP TS-870U-RP Turbo NAS server is equipped with an Intel Celeron G540 processor, which is based on the 32nm Sandy Bridge architecture, and is clocked to 2.4 GHz, according to QNAP. The current retail component from Intel is clocked at 2.5 GHz, so I don’t know if QNAP is underclocking the CPU, or they are getting a special SKU from Intel, or if it’s really running at 2.5 GHz, and the marketing collateral is just behind the curve. There is 4GB of DDR3-1600 system memory installed at the factory, and it’s expandable all the way up to 16GB by adding more 4GB DIMMS into the three empty DIMM slots. The TS-870U-RP doesn’t have the top-of-the-line CPU in QNAP NAS servers – that would be the systems with Xeon processors, but a modern dual-core Celeron is still a huge step up from any Atom-based model. The only question is whether it has enough horsepower to max out the system performance in an eight-bay unit, and we’ll find that out shortly.
From this angle you can see the fan module a little better, as well as the power supply wiring to the main board and the backplane. The wiring from the redundant PSU to the two main PCBs is very straightforward and short. The main controller board has a familiar ATX arrangement, complete with a separate 4-pin connector for CPU power. The backplane PCB gets its own dedicated power connector, direct from the PSU, for all those power-hungry HDDs. If you think about how much current it takes to spin up twelve drives, with three or four heavy platters inside each one of them, it’s clearly a good idea to have substantial power cables feeding the board directly. Right next to the power connector is the dual-redundant 512MB Disk-On-Module (DOM) PC board which contains two complete, independent operating systems. If one OS fails, the system reboots with the spare OS, and then immediately starts to repair and rebuild the OS on the corrupted module. All this takes place automatically, without user input.
In between the power connectors and the rear panel are something you don’t see every day on a NAS server: x8 PCI Express slots, two of them. This is where you have to go if you want to get the full performance that the TS-870U-RP is capable of. Many users will only need one of these PCIe slots, since most 10GbE NICs come in a dual-port configuration, but products of this caliber need to have some degree of flexibility and future-proofing built into them. You can also put 2-port GbE NICs in each slot, for a total of six GbE interfaces, including the built-in ports. I strongly recommend using at least two of the 10GbE ports, if at all possible. The increase in system performance that you get is well worth the cost, even if you have to upgrade other components of your network. I’ll be testing this model with the QNAP LAN-10G2T-U, Dual-port 10 Gigabit Network Expansion Card, which has two 10GBASE-T ports, with standard RJ-45 connectors. Several models from Intel and Emulex are also supported, with options for fiber optic cabling and SFP+ ports, too. I’ve personally tested the Intel X520-T2 (E10G42BT) adapter on a similar QNAP Turbo NAS and also had a good experience with that combo. The firmware instantly recognized the 10GbE NIC and there was no manual configuration required to get it running.
The two fans are 70mm units from premium Taiwanese supplier AVC that are 25mm thick and PWM controlled. They are designed to handle higher backpressure than a typical PC case fan sees, both because of the layout of the device and the fact that it may run 24/7 for years without anyone cleaning it. Because cooling is such an important element of the overall reliability for devices like this, there’s no good excuse for failing to clean things on a regular basis, especially since the modular fan assembly is designed to be quickly and easily removed and replaced. The electronics obviously need their fair share of cooling, but with up to eight HDDs crammed into a tight space, there is a great need to keep them cool, as well. Hard drive life is closely linked to operating temperature, and drive life is definitely something that almost all users of this unit will be concerned about.
Near the middle of the TS-870U-RP, the main board ends, and several PCIe edge connectors transfer the signals to a vertical board that serves as the backplane for all the SATA HDD connectors. It’s not just a passive board, there are drive controller ICs and a large FPGA chip located on the backplane. This is consistent with how QNAP builds their larger tower models, putting the controllers closer to the drives they are responsible for. Each Marvell 88SE9125 SATA controller chip handles two drives, so the board isn’t littered with these ICs, but they’re easy enough to spot. There’s a fairly large open space above the drive bays; on the 12 bay TS-1270U-RP, which shares a similar chassis, this space would be filled with drives. It’s not only the chassis that’s similar; the main PC board is silk-screened with a TS-1270 designation. There are some empty solder pads where a third instance of a controller IC would probably be installed, were this board built up to the full TS-1270 specs.
The memory controller is integrated on the Intel Celeron CPU, and it’s designed to handle DDR3-1066 and 1333 memory modules in its native configuration. The QNAP TS-870U-RP comes standard with 4GB of DRAM, rated at DDR3-1600 CL11, which is installed in one of four DIMM sockets located on the main board. The specs for the TS-870U-RP call out a maximum memory capacity of 16 GB, which is less than the 32GB maximum addressable size of the CPU, but more than adequate for a NAS running Linux. Based on my testing, straight data transfers use very little of the NAS memory capacity. There are hundreds of more challenging apps that you can run on a QNAP NAS though, and the extra memory will have a bigger impact on some of those.
The latches on the DIMM socket where the factory memory was installed are held firmly closed by a nylon cable tie, installed during the system build. At first I thought it was some sort of anti-tamper measure, but I think it’s really there to make sure the memory module doesn’t get loose. There’s actually a lot of vibration in data center racks, mostly due to hard drives and cooling fans, so it makes sense to tie everything down tight. Airplanes also have a lot of vibration, and I can tell you from experience shipping machinery to Japan, that things WILL loosen up over the course of a trans-oceanic plane ride.
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 half the story….