sacah.net

Raspberry Pi for always on server

posted by sacah on raspberry pi, project,

Overview

The following is all in AUD

So I leave my main PC running 24/7 as it runs a VOIP server, shares our photos and videos to the internal network and runs SABnzbd. It's not doing much compared to the power required, over a 2 day period it averaged 212W. So leaving it on 24/7 means it will use 1852kW over a year. Costing $463 for me to run.

Looking at when I'm actually using my Pc, it's about 73hrs a week, leaving my Pc running without anyone using it for 95hrs a week. This is using 1047kW a year, costing me $262.

For years I had been meaning to get a low powered Pc to do the 24/7 basics, allowing me to switch my Pc off, finally I got around to looking into it. Initially I wanted an x86 Pc, but after much research it seemed I'd have to get a laptop for best power usage of about 10W, it would be a larger physical footprint and cost more to purchase.

So then I started looking at ARM based solutions, and came across the Raspberry Pi, which I now have running 24/7 sharing my photos, running Mumble and checking my news groups. After monitoring my setup for 260hrs, it had used 1.4kW. This puts it about 47kW for the year, costing me just $11.

So that left me with $251 to set this up and make a saving on my first years power bill. Every subsequent year is all savings though (-:


Given I have 110gb of Photos, I wanted something cheaper than SD cards for my storage needs, which meant an external HDD. As I'm looking to build this as energy efficient as possible I didn't want to power the Raspberry Pi and HDD on separate power packs as there are inefficiencies in the conversion, so I decided to get a powered USB Hub, and run the Raspberry Pi and the HDD off this.

Also means if I need to add more storage down the line I can just plug more HDDs in.

The Build


From MSY
  • Western Digital WD WDBBEP7500ABK-PESN My Passport 750GB Portable Drive. 2.5 USB 3.0 HDD - $46
  • Channel+ UH340 USB3.0 4 Port Hub With Power - $25
  • TP-LINK TL-SF1008D 8 Port 10/100 Switch - $12
  • 8GB Sandisk SD (SDHC) - $7
From Element14.com
  • Raspberry Pi, Model B, 512MB - $36
  • Enclosure, Raspberry Pi, Black - $9
  • Cable, USB A M - Micro B M, 1.8M - $3.80

I went with a 2.5" portable drive because they are meant to be powered by a USB port, and the specs state that a USB device shouldn't pull more than 500mA. So at 5v that would equate to 2.5W.

Here is the power usage as things were added:
USB Hub - 0.3W
USH Hub + HDD - 2.4W
USB Hub + HDD + Raspberry Pi - 4.9W
USB Hub + HDD + Raspberry Pi + Switch - Transferring 110gb of Photos at ~1.4mb/s - 6.7W
USB Hub + HDD + Raspberry Pi + Switch - Transferring  at ~7.5mb/s - 7W

Currently I have the following running:
mumble-server
SABnzbd
samba