I recently put together a very affordable system to run crashplan and perform secondary NAS duties. I chose an AMD 5350 system on chip (SoC). I have used many Intel Atom boxes, and they chips are great, but always found the motherboards lacking in I/O. The 5350 APU series is socketed; you can choose your own motherboard. I paired it with a ASUS AM1M-A motherboards. This was one of the few motherboards I could find that had two extra PCI-Express 1x slots. The motherboard has two on-board SATA3 connectors. I installed on IO Crest SATA 4 Port SATA controller to provide four more ports. the trick to this configuration is that the PCIe 1x slots can not provide more than ~500mb/s of bandwidth. A SATA controller will quickly become saturated using more than SSD. The bandwidth is more than enough for multiple mechanical disks.
I also chose a Cooler Master HAF XB EVO case. This has four internal 3.5″ bays and four external 3.5″ bays. I’m using brackets to pack two SSD’s per 3.5″ bay.
All the hardware listed here works flawlessly with Ubuntu server. No extra drivers required.
Samba transfer rates are about 130mb/s with the SSD and 110mb/s with the mechanical disk. 130mb/s is not real as this exceeds one gigabport ethernet port speed. Crashplan transfers about 25mbit/s.
