I recently started searching for a power- and price-efficient engine for modest-sized NAS, running OpenSolaris (Nexenta) of course.
The idea to go to Intel ATOM first comes from their high power efficiency (1-13W TDP). To really benefit from it, do not only take into account the power used by the CPU, but also the whole motherboard (you know, chipset and GPU [Graphic Processing Unit]).
ATOM is supposed to dissipate so little heat that a fan might not be necessary, so most motherboards for ATOM ship with passive/fanless cooling. I still wonder if it should not rely on some cooling offered from the case itself, especially when mechanical disks are part of the equation.
To fully benefit from OpenSolaris, and ZFS, a 64-bits CPU is recommended, and multiple cores would benefit a ZFS NAS without any doubt. So we are left with two families, or rather generations, (this is a shortcut, but it makes sense given the tiny pricing difference), the ATOM 330 and the ATOM D510 (have a look at http://en.wikipedia.org/wiki/Intel_Atom). At first glance, they are quite similar, except the D510 embeds a GPU on-die, which means its 13W TDP is about all it gets, while a 330 motherboard as a whole (including an added GPU) will significantly draw more power than the 8W advertised. And honestly, we don’t care about the performances of this GPU.
Then, most motherboards are somewhat limited in size, which means many extensions are just not available here:
- RAM slot number (many times they are even SO-DIMM ones) and speeds, and lack of ECC support
- PCI(e) slot number
- SATA/PATA connectors
- NIC numbers
Note that despite the restricted on-board size, most motherboards present a lot of different external connectors (USB, DVI, D-SUB, PS/2, IEEE 1394, …).
And finally, most motherboards only ship in mini-ITX form-factor, which is not even really compatible with (micro)ATX, though some claim it (is this real, I honestly can’t tell). This clearly makes it difficult to find an inexpensive, yet solid, case to host it.
Compare all that to regular AMD or Intel CPU and motherboards pricings, and you will see what I mean in this article.
So Intel’s ATOM is (not yet) wonderland for OpenSolaris-based NAS today. But I will probably try some day anyway.