Nov 03

In the interest of saving power I decommissioned our old home server system several months ago.  Initially my grand hope was to migrate our home monitoring system to our existing low power consumption NAS server machine.  Unfortunately, that vision didn’t pan out and I ended up building a new home server.

Low Power Home Server

Background

Why did my NAS migration effort fail?  Well, I got tired of pulling my hair out trying to get the Perl-based thermd home systems monitoring application running on the ARM processor-based QNAP TS-109 Pro NAS server.  The thermd application didn’t run properly with the version of Linux and it was a major hassle to get all of the dependencies installed.  I don’t fault thermd at all – it’s a great application, but it isn’t claimed to work on non-x86 systems.  Since the goal of migrating this always running application to the NAS server was to save power by not running a separate dedicated server, I had to step back and consider an alternative approach.

My fallback plan was to assemble a custom home server system using an off-the-shelf x86-based processor and motherboard that would enable me to use a popular Linux distribution.

Since I expect the home server to run at least 10 years without the need to replace any parts, I wanted a solution that had a minimum number of moving parts.  Fans and traditional disk drives would be bad in this sense as these are often the parts that die after just several years of use.

Bill of Materials

After a fair number of hours researching my options, here’s the list of components I purchased:

So for around $460 I assembled a zero noise, zero moving parts, low power consumption (19 watts – see details below) x86-based home server.

Packaging Uboxed Before Assembly Low Power Home Server

Solid State Hard Drive

I opted for the 8 GB solid state drive because:

  1. I wanted to experiment with this up and coming technology
  2. I wanted a low power solution that would last a long time

Since we are storing all of our important data on the existing NAS server, I didn’t need much system drive capacity on the home server system. If you want to save some money on the SSD, you could opt for an MLC rather than SLC design.  However, you will get much longer service life out of the SLC SSDs.

I didn’t seriously investigate using either an IDE-compatible flash card or an SD card as a boot device.

The specs on the 8 GB SSD are:

  • Reads up to 135MB/s, writes up to 96MB/s
  • Power consumption: 0.6 idle, 1.9 read, 2.2 write (watts)
  • 1,000,000 hours MTBF

Alternative Approaches

Jetway? If I had known about it earlier, I would have seriously considered one of the Via processor-based Jetway CPU + motherboard combination boards. Going this route may have saved $80 or so to bring the overall system price down below $400.  I don’t know if they are any good compared to the VIA combos, but I suggest researching them if you are considering a similar solution.

Other options? If you don’t mind the noise and power consumption of a fan, you don’t need gigabit ethernet and you don’t mind using spinning rust for a hard drive, then you could shave off another $100 or so by going with a less expensive board and CPU combo and a much less expensive drive.  Taking this route, I suspect you could get a small form factor system with similar power consumption for a bit over $300.  The number of min-ITX combos available is mind numbing.

What bout the new Atom processor? I also considered the new Intel Atom processor, but the only motherboard available was the D945GCLF .  This antiquated chipset really impacts the overall power consumption performance.  Tests show that this combination resulting in over 40 watts at idle!  Since the Atom processors are rated at < 10 watts, the chipset is consuming a lot of power.  The upside of this combination is that it costs only $80 or so.  So $250 or so would get you an Atom- and conventional hard drive-based system in a mini-ITX form factor.

Home PC? Given the extremely low cost of home PCs these days, my server’s total system price might sound rather high.  After all, you can purchase a mini tower with a 2+ GHz Celeron for under $300.  That’s with a conventional disk drive and a system that will consume 55 or so watts and pump out 190 BTUs of heat at idle.  (Suspend and sleep states don’t apply in this always active home server role where monitoring and other tasks are occurring almost constantly). Of course, if space is at a premium, the small size of the mini ITX enclosures is a real boon over even mini tower PCs.

Laptop? Another alternative for a home server is to enlist an unused laptop.  Typically, laptops consume around 20 watts at idle and they don’t take up much space. However, you’ll still have a spinning disk and the laptop will likely generate more heat than the home server specified above.  Plus you might not have gigabit networking on the laptop.  I don’t know how long a laptop might last running constantly, but you could argue that you’d just buy another used one for $100 or so when the current one fails.

Assembly

Putting the pieces together was simple.  My 7 year old son and I had the parts put together in about 90 minutes.  We had to look over the motherboard documentation to ensure that we were using the correct connectors for the SATA drive and the enclosure’s front panel indicators for drive busy and such.  Since this was our first assemble from scratch effort, we took our time.  Someone more experienced could have had the parts together in 20 minutes or less.

I didn’t connect the enclosure’s integrated fan because the motherboard is a passively cooled design.  Note the huge heat sink fins in the pictures above.  I had also read that other people using this enclosure with this board had good results.  Besides, there shouldn’t be much heat at all generated from the SSD.

Software

The hardest part was installing the operating system.  It took a lot of fiddling with the BIOS settings to get things just right for the OS to work with this motherboard and CPU combination.  Since booting with a USB stick didn’t work for us (probably due to the age of the stick we were using), we temporarily hooked up a USB DVD drive for the OS installation.  Once I have a chance to document them, I’ll post the BIOS settings that worked for us.

I loaded up Ubuntu 8.04 server on the system and configured the server to mount several NFS shares from the QNAP TS-109 Pro NAS server.  Although I’ve been using the thermd application for more than a year, this time I migrated my data to MySQL and configured thermd to write all of its monitoring data to the database. This enhancement is really nice in that it’s easy to write scripts to extract data from the database.  I am using Webmin to schedule backups of the thermd database tables and other files of interest to the NAS server.

The straightforward heyu X-10 tool enables the server to control various home systems.  A series of cron jobs check temperature and humidity levels outside and inside our home and send on and off commands to inexpensive X-10 wall warts and low voltage relays that control the humidifier, dehumidifier and hot water recirculation pump.

Power Consumption

On the power consumption front, I am seeing the home server draw about 19 watts.  That number made my effort all the more worthwhile given that the old server likely consumed 150-200 watts and dumped a fair amount of heat into our home.  At a rate of $0.09 KWH, it will cost a little over $15 per year to run the home server.  This is a useful calculator for estimating energy costs. I’ve been using a Kill A Watt EZ P3 meter to measure the power consumption.

Overall

I’m pretty satisfied with the solution. Sure, I might have shaved off $80 by investigating the Jetway option, but that would have entailed even more research and may not have worked out as well.  I suspect that Intel’s Atom processor will be available soon on more modern and power efficient chipsets that are much less expensive than the Via combo that I purchased.  The advent of those Atom boards will put price pressure on the Via-based combinations.  Before going with a Via processor-based solution, I’d recommend looking at whether the newer Atom-based boards have become available.  And of course, Via has a new Nano processor line emerging to compete with the Atom.  It never ends…

5 Responses to “New Efficient, Low Power Home Server”

  1. [...] with HDDs, installation and configuration is simple. We’ve been using a small 8 GB SSD for our home server for several years without any [...]

  2. mabuhay says:

    Great article, thanks. I enjoyed reading your experiences, especially the part about the alternatives and the software (heyu X-10 sounds interesting). I am also setting up a home server right now, using a Plugcomputer (GuruPlug Server Plus) and I am planning to add some home automation, so I guess I will return soon to see more about your project. I started to keep record of my progress on http://www.myownhomeserver.ch, but I still have a long way to go ;)

  3. [...] had our low power consumption home server running for several years, but I hadn’t gotten around to performing a full system image back [...]

  4. Amaltea says:

    An atom netbook consumes 6 or 8 watts at idle and around 20 w full cpu (with screen off obviusly). It’s an very good option.

  5. Egil says:

    Awesome. I have/had a (its purpose was done in January 2011 as a firewall/router) Mini ITX 533Mhz with some HDD’s in a nice 1U rack. Worked wonderfully and had good uptime, max 7 days of downtime tru 7-8 years of usage. After five year the motherboard silenty died. (If I was more careful with ESD it may lived longer) I bought the same motherboard as a replacement.

    The powersupply died without a explosion after 3-4 years. It was burned out, I suspect that the reason was that I had 3 HDD, and the powerusage was very near 60watt. I changed the powersupply to 80 watt, and it died after a few years. (!) Damn. The external 65w powersupply are still fine after 7 years. Weird. Now it’s got a common 180w PSU with a fan and all that crap – I was in hurry! I bought recently a PICOPSU at 90w, let’s hope that it’ll live long and prosper.

    So beware the powersupply may die after 5 years or so.

    I still love that machine, it’s called “grandma” (on the father’s side) and today I decided that I wanted to use it as a NAS/fileserver.
    it may not be heavily used as before, but I’ll enjoy every moment with it! :D

Leave a Reply

preload preload preload