Can you build a Linux server for web, email, printing, and 4 terabytes of media serving purposes from commodity x86 parts, and come in under 20W? Absolutely!

If you run a server at home 24/7, and it uses, say, 150W, that’s 1.3 MWh (megawatt-hours) of electricity per year, and probably $130 or so of utility cost. You can do better!

I recently assembled a server with the following specs:

(note, some Amazon product links follow):

Jetway JNC9C-550-LF Mobile Atom Mini-ITX motherboard

Ituner Networks Pico-PSU 90W [amzn]

60w (12v/5A) AC-DC Power Adapter, efficiency level V

2x Kingston 1GB 204-Pin DDR3 SO-DIMM DDR3 1066, p/n KVR1066D3S7

Western Digital WD7500BPVT 750GB 5400 RPM 8MB Cache 2.5″ SATA drive [amzn]

2x Western Digital Green WD20EARS 2T 64MB Cache 3.5″ SATA drives [amzn]

LIAN LI PC-Q11B case

Red Hat Enterprise Linux 6

Out of the box, the Kill A Watt [amzn] showed about 20W. After running this script to further push down some power consumption, it came in at 18W:

#!/bin/bash # Idle media disks # (should set shortish spindown time too...) hdparm -y /dev/sdb hdparm -y /dev/sdc # 100baseT saves power over GigE ethtool -s eth0 autoneg off speed 100 ethtool -s eth1 autoneg off speed 100 # kill Wake On Lan ethtool -s eth0 wol d ethtool -s eth1 wol d # set ALPM on SATA links for FILE in /sys/class/scsi_host/host?/link_power_management_policy; do echo min_power > $FILE done # Set PCI Express power management echo powersave > /sys/module/pcie_aspm/parameters/policy # Try to keep 1 core idle when possible echo 2 > /sys/devices/system/cpu/sched_smt_power_savings # Disable the nmi watchdog echo 0 > /proc/sys/kernel/nmi_watchdog

Ok, idling the 4T of storage might be cheating a little, but in reality, they hold music and movies, and simply do not need to be spinning all the time. (Without these drives in the system, it comes in at about 16W.)

At 18W, that’s 158 kWh/year, or about $16. An 88% reduction! And, the utility savings would almost pay for the motherboard!

I don’t know if non-mobile Atoms would fare as well; my original test of an Atom motherboard was lackluster in part due to lack of power management, but then I didn’t have the efficient power supply either, so I’m uncertain. I’d imagine that the new AMD E-350 (Brazos) motherboards would do very well too, but I’ve not been able to test one out.

And, one more bit of full disclosure – sandeen.net isn’t running on this box yet, the migration isn’t complete. Still, quick tests of WordPress running on the platform don’t seem any slower than the current old AMD box (a 40W hog ;) ). And if LKML keeps spamassassin really busy, maybe it’ll inch up in power a bit. I’ll let you know when you’re reading this blog on the new machine, and what the average wattage draw is over a week or so.

So, for you geeks out there with home servers, how much power does it draw? Would you consider something like this for your next build?