Just wanted to post up a build thread for a box I built about a month ago that has been rock solid. Wasnt sure about building in a small case but it really worked out well.
It started off with a search for a 4 bay NAS case, I ended up going with the In Win IW-MS04 that came with a 265w flex power supply and a 4 drive SATA/Mini-SAS backplane supporting up to 6Gb/s for $150. Another great feature of this case is it has a slide out motherboard tray which I found to be a great benefit working inside such a small case.
Since the case supports Mini ITX I went with the MSI H110I Pro, has 4 SATA3 ports, 1 x M.2 and supports booting of a NVME drive so I didn’t lose one of my drive bays to the O/S. I didnt notice at the time that the on-board NIC was Realtec but it has been working great, I prefer Intel NICs. Picked the board up for $70
For processor and memory I went with a Intel Pentium G4600 3.6 GHz dual core processor for $80 and 2 x 8GB Kingston PC4-17000 memory for $90 each.
Rockstor is booting off a Toshiba OCZ RD400 NVME M.2 drive on the motherboard and the storage is 4 x WD Red 4TB drives. I had the Red’s in another box so that was one less expense.