I'm about to start the process of updating my file server systems. My current rigs are older Core 2 Duo machines of one sort or other, each on full ATX motherboards. Most of them use a combination of onboard SATA and IDE port and 8 or 16 port SATA/SAS controllers. They mostly have power supplies in the 500 - 700W range.
Do you have any stats (UPS load estimate, watt meter, etc) on how much power the components draw now?
My file servers are running RHEL or Centos right now, though looking forward I suspect I'd be better off with a more up to date platform. I could look at another Linux, with BSD or Solaris for zFS support, or to Windows Server since that's what I spend most of my time using these days.
CentOS 5 is still maintained for several years to come and CentOS6 is right around the corner (or use Scientific Linux if you want it now). I don't see any requirement to move away from this platform for a file server.
However, zfs is tempting if it can meet your raid and fs needs, vs using a another fs on top of MD raid - I would stay away from LVM altogether. Although I'm probably more likely to go with a BSD or Solaris Unix platform if I required ZFS, as ZFS on linux is probably not widely used and vetted compared to Solaris/BSD.
If sticking with Linux, I'd use ext4 - Many Linux distributions are moving to it as the default (google uses it exclusively on their servers as well as all android phones). Ext4 which promises better fsck and other optimizations for large file systems.
Have you thought about using FreeNAS or another NAS based distribution?
I'm contemplating a move to Atom-based machines to get power consumption down while at the same time migrating my disk arrays to what will probably wind up being arrays of 3TB drives, but while I'm mulling it over, perhaps it might be interesting to talk about here.
Any modern Intel CPU is going to be pretty efficient at idle - anything in the same family (
LGA1155,
LGA1156 ) should have roughly the same idle draw. My guess is that the disks are going to be using a lot more power than your (mostly idle) CPU. I would focus on that aspect and choose fewer larger drives and drives that are the most efficient. I think the next big efficiency gain would be in the PSU, add-in cards, and lastly look at the CPU and mobo.
Personally, I have been recommending 3.5" Seagate ES and WD RE drives for those who want SATA based file servers. These drives are limited to 2TB, which probably says something about the reliability of 3TB drives. 2.5" inch drives offer a small power savings over 3.5", but the (much) smaller capacity of the 2.5" drives doesn't begin to make up for the power savings.
Looking at WD's specs, they have an RE4-GP which lists a max of just under 7 watts and an idle draw of just under 4 watts. This compares to the standard RE4's 11/8watt draw. WD also has an AV-GP model which claims 4.5/4 watts. All of these models are rated for 24/7 duty and the RE series has a 5 year warranty. Seagate doesn't have a low power ES, but their standard ES does have slightly lower draw than WD's RE4 series.