NAS/fileserver project—RP64 in 1U ATX/ITX case (comments welcome!)

[TRS-80]

Regarding the mounting of the RP64 board to the ITXATX case: Why not make an adapter plate (metal or 3d printed), screw the RP64 to that and then screw the adapter plate to the case?

For that matter, why not just use regular standoffs and if necessary, drill another tiny hole or two wherever needed?

I have acquired an entire boxed assortment of them (in different lengths, and including nuts, washers, etc.) off AliExpress for only a few dollars.

EDIT:  Oops, totally forgot to talk about power. 

Since I am planning similar build (although not in rack mount case) I thought I would provide power similar to what I have done for other ARM (Cubietruck) based NAS in the past which is an appropriately sized Mean Well power supply.  Full ATX (or even those little pico ones they sell) are not really appropriate, mainly because we neither have (nor need) the ATX power connector itself.  Cubietruck sold a little add on board to help distribute power, but with the adapters Pine sell in the store (and slightly more DIY), we can accomplish the same thing.

Now, in my case, I am planning 3.5" HDDs, so I calculate power needs more like 8-10A in total for the board and (2) 3.5" HDD.  Which is a little more than you, but overall the planning process is the same.

BTW, I am not sure 5A in your case is "plenty" as I think the ROCKPro64 can use up to 3A by itself, then you have the drives in addition to that.  Well, that is the size power adapter they sell for it, anyway (3A I mean).  I am actually curious what real expected usage is, as that would actually help all of us in planning.

Anyway, turns out in the range I am looking (~9A I figure) these power supplies start to come in 4 pin DIN configuration (at least my preferred Mean Well do) instead of the standard barrel like what was on the Cubietrick (and what is on the ROCKPro64 itself).  I was looking at GST120A Series (GST120A-12 more specifically, which provides 8.5A @ 12V).  Although they have a lot of other models available, too, if you think your power requirements are less.  In fact I already scored 3 of them used off eBay for 60 USD total, shipped (only 20 USD / ea!).    But there are many more and seem to be common and therefore reasonably priced and readily available.

Anyway, so then I ordered some DIN panel mount female plug, for the outside of whatever case I end up using.  I plan then to just solder some (appropriately sized) wires between that plug and into a barrel jack for the board itself, and also into one of the adapters they sell in the store which takes 12V in and puts out the 12V + 5V in a SATA power plug which each drive will need.  Tidying it all up with shrink wrap, etc. of course.