So far, I’ve been using nothing but RAPL and my servers’ PMBus support to measure power usage. The problem is, this means I can’t measure the rest of my rack – only a couple servers. I’ve still got two switches, a mini PC, and a cable modem. Plus, the router host does not have PMBus, so I don’t have any measure of how much power it consumes outside of the CPU and memory.

The solution to this is a metered-by-outlet PDU. The problem is that these are expensive – certainly to the point where it is never going to pay for itself in a timely manner. Buying one secondhand is the only economically viable way to do this, and it’s going to be a very old unit.

The original Raritan PX lineup can be found for reasonable prices. They have a few models that take standard 120v single-phase input and have standard NEMA 5-15R outlets. Let’s buy one, and see how it goes.