Building a Low Powered and Silent Atom Based Server (Sheevaplug alternative)15 Sep 2010
After I had problems with my sheevaplug power supply I had lost faith in the device and didn't trust it to survive being on 24/7 without exploding/setting on fire etc... so after NewIT kindly fixed it I sold it. This left me with no server to mess with so I decided to try and build a new one - the two primary requirements being that it used as little power as possible (ideally around 10W - the same as my sheevaplug with hd and usb hub) and was totally silent. In this post I'll describe what I came up with.
My requirements for quietness and low power stipulated that a fanless system would be best so as a balance between low power and performance I choose a 1.6GHz N270 atom based motherboard (the Intel D945GSEJT) which consists of a mixture of laptop and desktop components while providing ample speed for my requirements in silence. The motherboard is also nice because it has an internal DC-DC power supply meaning that only an external DC power supply is required, no extra faffing as with a lot of ITX boards on the market. I added 2GB of RAM to this, the maximum allowed by the motherboard.
I decided I could cope with the slight noise generated by a hard disk so went for the best value 2.5 inch disk I could find (A Hitachi 250GB), an SSD was beyond the performance required and budget of the project!
When choosing the case I went for the quite large Lian Li PC-Q07, it has space for a full atx power supply but I had in mind that I wanted a system that I could grow and modify if I thought of a new use for it so currently I have a motherboard and small hard disk in a case able to accommodate a full ATX PSU, 5.25" optical drive and 3.5" Hard Disk...I mentioned space was consideration!
My current Linux distribution of choice is ubuntu so I chose ubuntu server for the machine as it's what I'm with familiar with and does everything I need. I usually run apache, mysql, php, python, mosquitto (mqtt broker) and irssi (IRC) on the machine 24/7 and so far it has performed flawlessly. I used powertop for power optimisations.
Power ConsumptionWhen I first started out using the sheevaplug one of my main motivations was the low power usage, as my needs grew the sheevaplug + SD card became a sheevaplug + powered USB Hub + USB HD all in all consuming around 10.5W of power, therefore this was my target for this machine. In addition to using low power components I also used PowerTOP to optimise the power usage of the operating system. PowerTOP accomplishes this by ensuring cpu scaling is working correctly and powering down systems which are not required.
Before carrying out optimisation with powertop my mains power consumption was ~ 14W idle and after nearer the target of 10.5W, now using ~11-12W:
The low power consumption I achieved surprised me as the sheevaplug has been developed with this as its main aim and sacrifices processing power to achieve it. My atom system could rings around the sheevaplug in terms of processing power and comes within around 1-2W in terms of power consumption...so much as I'd like to love the sheevaplug the bad design and service provided by Globalscale force me to take the less cool but more functional route.