At the close of Part 1, I asked if the performance that I obtained with FreeNAS was all that an Atom-based platform could deliver. Given the results that I obtained using Ubuntu Server and mdadm based RAID, I think I the answer is a definite "No"!
As the testing showed, I obtained a 2X write speed improvement and 15% read speed improvement simply by changing the OS used in the Atom NAS. While the combination of Ubuntu Server, mdadm and Webmin might not be as easy to use as FreeNAS, the improved performance definitely makes it worth the switch.
I wanted to see what the performance was like for the Ubuntu combo and a Windows XP client. But when I went to restore the Ghost image, I ran smack into the gotta-load-the-SATA-driver-on-a-system-with-no-floppy-drive hassle. Such is the price I pay for having an too-old version of Ghost (which I hardly ever use). So it looks like I better set aside a day to set up a dual-boot XP / Vista system to make this easier for future testing.
Stepping back to look at the big picture of Atom's possible place in future consumer NASes, I don't think you'll be seeing it on lower-cost products. Given that Atom is more a general-purpose computing platform vs. a dedicated NAS controller, I'd have to say that it may be hard for an Atom-based system to be cost-competitive with a NAS based on, say, Marvell's Orion.
So Atom is more likely to find a place in the higher-end RAID 5 systems like the Intel SS4200-E, QNAP TS-509 Pro and Thecus N5200 Pro, which all use Intel's Celeron M 420 or the Synology DS508, which is based on a Freescale MPC8543.
As for building your own NAS with the only currently-available Atom mobo from Intel, there is both good and bad news. The good is that it will probably produce a dual-drive NAS that has performance higher than any off-the-shelf product that you can buy. I say "probably" because my Ubuntu tests all used a Vista SP1-based client, which would probably also produce a performance boost for the RAID 1 products close to the top of the NAS Charts. I can't know whether the Thecus N3200's (the current leader if you take out the quad-drive Intel SS4200E) 20 Mb/s average write and 24 MB/s average read speeds would increase to anywhere near what I got with the Atom NAS unless I test it. And that product has gone back to Thecus.
The other good news is that building your own dual-drive NAS with Intel's board won't cost you that much more than buying an off-the-shelf alternative, as long as you're not fussy about the case used. If you already have a case that can take a mini-ITX board, then your cost will definitely be less.
The bad news is that Intel's board has design tradeoffs that result in a less than optimal NAS solution. The Northbridge chip is responsible for a lot of the 50W power that is 2X what other dual-drive NASes draw. And the fan that's required to cool it means one more thing to cause noise. The other limitation is the onboard 10/100 Ethernet that forces you to use the single PCI slot for a gigabit NIC. But, as we have seen, a PCI gigabit NIC caps your possible throughput to a little under 70 Mb/s. So if you're looking to make the most of a gigabit LAN connection, you won't do it with this board.
Still, if you're looking for better performance than you can get with current off-the-shelf RAID 1 NASes and don't mind putting in a little sweat equity, the combination of Intel's Atom mobo, Ubuntu Server, mdadm RAID and Webmin can make for a sweet little NAS.