Files server:

On 05May2009 (5pm) I’ve installed the Watt Meter on the file server PC to get an idea of how much juice it uses. The File Server is currently running 4 x 250gig Segate drives, and 1 x 500gig segate drive, on a VIA EPIA EN15000G Mobo.

So far (10pm 06May2009), it’s used up 2.24kWh, and averages about 90W while under usage (writing a 5gig file to it)

The next morning (06May2009) two drives were spun down, and power draw was down to 70W.

As of 24 May 2009, the file server has used up 34.46kWh.

Working out the usage/costs:

34.46kWh over 19days = 1.81kWh/day = 662kWh/year => @ $0.10/kWh, cost/year = $66.2

A few other thoughts:

I considered putting a different mobo in the file server machine, to add more speed, howevet, the VIA mobo can’t be beat for power usage.

I know the computer eats between 70W-90W (total power at the plug). assuming on average, each drive eats 10W, that’s 50W total (for the 5 drives). So the Mobo, power supplty and SATA card must be eating 20W-40W.

Still need to think about this motherboard upgrade…

UPDATE 05August2009

Did the MoBo update. The Via board’s LAN port got fried in a lightning storm.
New board is a Gigabyte GA-MA74GM-S2 with an AMD Sempron LE-1250 CPU (45W) .

The system pulls in 102W, which is only 10-30W more then the old system. Not bad.

More accurate measurements:

Under no load, with all 5 Seagate drives shut down, the system was pulling 69W
Under load, with all 5 drives active, doing a parity check, pulling in 119W

Xen server:

Next step is to get the Watt meter plugged into the xen server and do the same over the course of a month or more.