What is the best way to calculate total power consumption of an unraid system? Idea is to keep it on 24/7 but do not want to waste  energy.

 

Thanks

 

Well, the only way to really get real-world numbers is to use a Kill-A-Watt or similar voltage meter.  Of course, then you have to actually have all the hardware already.  I'm guessing you want to calculate the power consumption before you buy the parts.

 

There have been some benchmarks performed by forum members, but the results are sometimes conflicting.  There are a lot of factors involved.

 

Generally speaking, I can recommend the i3 and the Atom processors as using the least amount of energy.  The i3 is optimized when combined with an I55 motherboard.  Runners up would be the Intel Celeron 430 and the AMD Sempron 140.  The latter are both budget options, as well.  The Atom is also passively cooled, so that's one less fan spinning.

 

The less RAM sticks you use, the less power they pull.  So if you want 2 GBs of RAM, get a single 2 GB stick instead of 2x1GB.

 

Definitely buy a motherboard with onboard video, as a separate video card will use more power (and likely be wasted on unRAID).  Also disable any unused features on the motherboard (this has the side benefit of helping your server boot faster).

 

Look for cases with good airflow designs.  The less work the fans have to do, the better.  Also opt for larger fans whenever possible.  A single 120 mm or larger fan can do the same work as several smaller fans, and be quieter and use less power in the process.

 

You'll definitely want to buy an 80+ PSU.  If you can afford it, 80+ Gold certified PSUs (I know Seasonic makes some) have the best efficiency rating and will therefore help you keep your power consumption down.

 

You'll also want to use only low power green drives, such as WD Greens and Samsung EcoGreens.

 

A PSU Calculator can help give you a rough idea of the wattage you can expect your server to pull.  However, your real-world measurements will probably vary.

 

So a lot of this depends on your budget.  If you have a lot of money to spend, you can build a server that idles around 10-20 W no problem.  Spin up may be 50-100 W (depending on the number of drives you have and other factors).  If you have a tighter budget, I recommend something like the Budget Box.  Cheap and efficient, but not quite as efficient as something like an Atom or i3 build.

 

Also keep in mind that if you spend $300 more to build a low power server, it may take years before you see that money back in the form of energy savings.  So you have to take into account how much you are actually saving versus the premium you have to pay for low power components.

Runners up would be the Intel Celeron 430...

 

I found no measurable power difference with a Celeron-L 440 and a Core 2 Duo 2.4 and 2.6 processor for regular unRAID usage.

 

I mention this so someone does not think they need to purchase a Celeron-L over a Core 2 Duo to save power.

If the choice is one of the two in your parts draw, use whatever you have laying around.

 

Where there will probably be a measurable difference is when you run the CPU core flat out doing some kind of compression, md5 summing ,etc, etc.

 

At idle or regular unRAID usage, I saw no power savings with the 35W processor.

Much good advice here already.

 

My i3 530 in an Intel mobo, with a 76% PSU idles at around 60watts (according to the UPS).  With three drives spinning (two of them WD green), it uses 80watts.

 

Choose a short spin-down time, bearing in mind your anticipated usage pattern.  Consider using s3 sleep mode if there will be long periods of no activity - this reduces power consumption to almost zero and my system takes little longer than the drive spin-up time to become active.

some BIOS have a setting so you can power up at a set time each day,  My FreeNAS box is set to power up at midnight do some backups and then power down again 2 hours later. Not sure how common a feature it is, or how useful it is for most people but its handy for me

Lots of info. Thank you....