The Thecus N8900 Internals
I'm asked all the time about the inner workings of NAS servers. Many people think these are made from off the shelf PC components, but in most cases that isn't true. The Thecus N8900 uses several specialized components that are designed by Thecus.
The CPU is cooled with a Cooler Master heatsink and fan that is actually very quiet. That doesn't mean the NAS is quiet, we'll get to that in a minute, though. Only two of the four available RAM slots are populated so you can easily add more memory. Our N8900 shipped with Transcend DDR3, 4GB per stick.
Here we see the expansion port area that has two free 8x PCIe ports and a 4x PCIe port. The single lane PCIe is used by the USB 3.0 card that has two USB 2.0 ports.
The NAS's internal software is kept on a 1GB flash drive that is mirrored to a second 1GB flash card. This is a redundant system.
There are two layers in the NAS so the motherboard is raised up more than it would be in most 2U servers. The raised area goes past the motherboard and into the drive bay area. Because of this, Thecus didn't have room for 80mm fans. The NAS has two 60mm fans that are pretty loud. We would have liked to have seen quieter 80mm fans used in the system. The fans can be easily hot swapped without shutting down the system if they need to be replaced in the field. The bracket system used on the N8900 makes removal and installation very easy.
The motherboard uses digital power switching just like high end motherboards used in enthusiast class systems.
This is the first time I've noticed the new CMOS battery that is about half the size of normal CMOS batteries. This allowed Thecus to save some space on the board.