Time for another incredibly exciting post about linux servers and their power use. I have built and tested my Atom server and I’m pretty excited to note that it uses 33 watts when idle and a whopping 37 when under heavy load. You can find a detailed description of the parts I ordered to assemble the server on another post on my blog, so I won’t go back into it here. I will need to make one change going forward though. Hitachi no longer makes the 80GB laptop hard drives that I was planning to use but Seagate’s Momentus drives are almost exactly the same power use. It is important to point out though that while these drives are laptop style drives, they spin and run at basically the same speed as desktop drives so performance on them is very good.
The good news right off the bat is that all the parts fit and work together nicely. I was initially concerned that the motherboard wouldn’t fit into the case I purchased. It’s designed for an ATX style board and doesn’t mention anywhere if it supports other boards styles. I don’t know if they planned for this, or if the Mini-ITX motherboard standard simply lines up with the ATX screw holes but the board fits fine. All the screw holes line up with no modifications at all. The case has something close to a million screw holes for just about every style of motherboard it seems. All of the cases cables work just fine as well and I have working power and reset buttons plus two USB connections on the front of the unit. I can’t ask for more then that.
I purchased a SATA drive cage to simplify the mounting of the 2.5″ disks in the large rackmount case. The reviews on Newegg’s site are mixed for this device I chose so I didn’t know what to expect. The unit is actually really well built and pretty simple to use. The drive cages don’t slide in as easily as some enclosures I’ve used, but I can’t imagine being able to do any damage to the drive or the enclosure when inserting the disks. Really, the only draw back is that the two small fans in the enclosure spin pretty fast and create a lot of noise. The back of the unit has a jumper though and when I switched it to lower the fan speed, I still get plenty of airflow and almost no noise at all. I think it’s really well designed and worth the $60 I paid for it.
I paid extra money for an ’80 Plus’ certified power supply. I paid about $38 for a 300W ATX power supply. I could have purchased an 300W non-80 Plus power supply for about $25 dollars, so I paid an extra $13 . I wanted to find out what kind of power saving the more efficient supply would provide me. I used a similar power supply that I already had on hand and hooked it up to the system to see what it would do. It’s a newer Thermaltake supply, not a cheap no name brand. Power usage was 42W idle and 48W under load. The Atom processor uses 4 more watts under load then it does on idle so I expected a 4W jump, but not 6W. Assuming we use the idle numbers from both power supplies that is a 9 watt difference. Not a whole lot. I did some calculations though and with the average 2008 power cost of $0.1644/kWh for my area, that equals about $1.07 per month of savings or $12.84per year. Power costs are always going up, at least around here, but assuming it stays at that level, in about one year the cost difference will equal out and I’ll start saving money. Seems like a good return on investment to me!
I guess the only real problem with this system is that the tiny motherboard looks silly in the massive case. This case though allowed me to use an less expensive off the shelf ATX power supply over a smaller, hotter and noisier power supply designed for smaller 1U rack mount cases though. So far, it’s as fast if not faster then the Pentium D machine this system will be half replacing. I’m going to add a second server to run my websites, instead of running them in VMs. I’m pretty excited about the end result and can’t wait to finally switch off the old system.
I’ve installed and tested both Fedora 11 and Ubuntu 9.04 and they both work great. All the hardware is picked up at boot and the system shows all 4 processor cores. Two of them are real cores, and the other two are hyper threading cores. The motherboard uses a Realtek chip for the Gigabit network interface and their is some chatter online about it being unstable. Thus far, I’ve not had any problems with it whatsoever. It’s possible that those driver issues have been worked out in the latest versions of the kernel and Linux operating system.
The whole system runs nearly silently since the Atom processor generates so little heat. It’s about 6 feet from me right now, and I cannot hear it at all. I’m pretty happy with the cost both upfront for this system and in the long run. My calculations say it will cost about $50/year to run. Not bad at all. The savings though continue through the rest of the system. Having lower power use at the server means I can use smaller, less expensive battery backups. It also means I’m generating less heat so I don’t have to worry about cooling to any measurable extent. Good stuff all around!
Topslakr
[Updated 6/20/09 – I adjusted the price I paid for the 80-Plus power supply. I thought I paid $50 for it but looking at my receipt it seems I paid only $38. I adjusted the paragraph to update all relevant information.]