QNAP’s TS-251B is a compact and quite attractive looking 2-bay NAS with its white front bezel and side panels. The silver grey front panel holds the power and USB copy buttons and the five indicator LEDs (reading from top to bottom they are: status, LAN, USB and two for drive activity).
The real panel is dominated by the grill for the 70mm cooling fan. Above it is the external access to the PCIe slot. To the left of the grill sit the three 3.5mm speaker and line out jacks, under which sits the HDMI v1.4b port. Under these are a pair of USB 3.0 Type-A ports clustered together with the single Gigabit LAN port. Finally there are a pair of vertically mounted USB 2.0 ports.
The pair of vertically mounted drive bays (that support hot swapping) are hidden behind a removable panel that makes up three quarters of the front bezel. This panel is held in place by a sliding lock housed in the front of the left hand side panel.
The drive trays are made of plastic and have grab handles moulded into them. The trays are held in place with small latches. Supporting both 3.5in and 2.5in drives, the larger drives are held in place by plastic strips that fit into grooves in the drive tray’s sides, and each plastic strip has pins that fit through the tray and into the drive’s side mounting holes.
These mounting holes in the tray sides have anti-vibration grommets fitted. If you want to make sure the drives are installed firmly, you can also use the screws provided to fix the drive via holes in the tray base. 2.5in drives can only be fixed via these holes in the tray base.
To access the memory DIMM slots and the PCIe slot you have to separate the two halves of the housing. This is a simple job that just involves removing two screws in the rear panel (top and bottom) and sliding the two sides apart. There is an indicator to show which way the unit unlocks sitting under the quick start label on the bottom of the unit.
The PCIe slot supports QNAP’s QM2-2S and QM2-2S-220A SATA SSD expansion cards and the QM2-2S1-G1T SATA SSD & 10GbE hybrid card, plain dual and single port 10GbE cards and USB3.1 cards.
Via the two SO-DIMM slots, the TS-251B’s motherboard supports up to 8GB of DDR3L-1866MHz memory.