Weblog – Thomas S. Iversen

I recently bought myself a spar’o’meter, (kill’a’watt like device) which is able to measure the power usage of electrical equipment. To my horror I found that my “lowpower” AMD fusion based server consumed around 50 watt! Clearely something had to be done.

Luckily I had the right piece of equipment at hand. A lenovo thinkpad T420 with a broken/shattered LCD. Any decent laptop is built to minimize power consumption, so using an T420 alone would save on the electrical bill, but I went a bit further. More precisely:

• Took off the (broken) TFT and disconnected it from the mainboar
• Took out the bluetooth module
• Took out the wireless module
• Disabled all unneeded peripherals, serial ports, usb ports,
• Bouht myself a 1TB WD red 2.5″, which consumes around 1 watt.
• Removed the DVD drive.
• Enabled maximum power settings in the bios.

I then put in 2 x 4GB of memory and together with the core i5 cpu, this would be a nice server with a built-in “ups”. On the software part, I migrated away from one big server years ago. I run esxi on my servers now. There was a small issue here, as ESXi 5.5 does not have support for the Intel Gigabit 82579 LM chip out of the ISO file.

This is not a biggie. You patch the iso with the correct driver for the E1000E chip using the esxi-customizer script and then you boot the customized .iso file.

I ended up with a esxi host that consumes 12 watt. A factor 4 better than my old AMD fusion based setup. And it feel snappier as well. The trade-off: I had to go from 2 x 2TB disks to 1 x 1TB. But that alone saved 10-15 watt.