Low power system for unRAID

For any "always on" box like unRAID, I want to minimize power requirements, heat generated, and noise.  My design criteria are under 50 watts, and a desired target of 20 watts or below in idle.  This of course usually results in decreased performance, but the performance hit is usually seen in increased resync times and write performance, and not in read performance.  That's would usually be acceptable for most HTPC users, and many other frequent users of unRAID (although of course not for everyone).  If others are interested in discussing hardware/software options for minimizing power and heat requirements in their unRAID system, I'll kick in what I know.

Someone pointed to the new $200 PC from WalMart with is an Everest C7D processor in a micro ATX mobo.  This is a very low power-consumption mobo (20 wats) with moderate performance.  You can buy the bare mobo w/ CPU for $70.  I may get one for "testing."

Another option is an Intel Geode processor.  Two to four times the performance of the C7D processor.  I use that for my Asterix box with linux cpuspeed governor set to "ondemand" (which will raise and lower Vcore and CPU frequency as needed).  It is passively cooled (no fan) except at the times of extended heavy processing, when the cpu fan will cut in for a while.  Power consumption measured at the AC input (the only real way to do it) is 42 watts, with two hard drives spinning.

If there is interest, I'll test both of these with unRAID.

One caveat, is that most of the low power consumption mobos are build for tiny footprint boxes and embedded systems, so they are usually mini ITX for factor (inly 1 PCI slot) or micro ATX (up to 3 PCI slots).  You won't likely be able to get a full-boat 16 drive unRAID box, but 12 drives is a possibility if you are willing to mix SATA and PATA.

So is there any interest in 10 or 12 disk low power or ultra-low power consumption unRAID discussion?  "Low power" being 50 watts and below, and "ultra-low power" being 20 watts and below.

I'm not sure a fully loaded 10-12 disk unRAID box could fit your specification for either "low" or "ultra-low" power.  I did a quick check on Western Digital's website and found the following specs for a single SATA drive:

Raptor 150GB drive (high performance):

Standby/Sleep:  ~2.5 watts

Idle:  9.2 watts

Read/Write:  10.0 watts

Cavier SE 500GB drive (mainstream):

Standby/Sleep:  1.0 watts

Idle:  8.4 watts

Read/Write:  8.8 watts

Cavier GP 500GB drive (power savings):

Standby/Sleep:  0.3 watts

Idle:  4.0 watts

Read/Write:  7.5 watts

So, unless I'm mistaken, a 10-drive unRAID server would draw 40 watts while idle and up to 75 watts during parity checks, even with WD's most efficient (power-wise) drives.

Oh that is definitely true... but the power draw of the drives is pretty much fixed... the drives draw what the drives draw... but generally under 1 Watt when spun down (I don't think many people use high performance Raptors in unRAID boxes, and if they do, obviously performance is most important to them, so this project isn't their cup of tea).

I may have been unclear in my goal.... my target is for a system that pulls less than 20 Watts for the *majority* of the day, and recognize that it will be over 20 Watts when doing parity checks or heavy I/O.  Or put another way, my design criteria is the be under 20 Watts at these times:

  - over night and when no data is being read or written

  - and when only reading data from one drive (such as when watching a movie over the LAN)

IMX, a typical HTPC or personal file server spends the vast majority of its time *not* doing heavy I/O.

10 drives spun down would still be less than 10 Watts.  A 9 Watt mobo like the J7F4K1G-OC or J7F2WE1G-OC (that idles at a fraction of a Watt) would still give you a system that spends most of its time at under 20 Watts. 

If we can talk Tom into getting cupfreq support into the kernel, the dynamic power performance will be vastly improved.

This sounds like a very cool project !!

For ages I have been looking for a case that were more logical in how heat is removed from the drives. Most cases is relying on vertical airflow, while it would be more logical if the airflow were down-up, with vertically mounted drives.

But unfortunately i have found nothing.

/Rene

Even with only 12 drives, you will still need a PSU capable of handling up to something like 200W considering everything. That sound too me much more than what a psu generally associated with those kind of system can deliver, and so you might have to use a beefier one, less efficient.

I'm not sure that kind of PSU can be that efficient to go down to 20 W on idle.

Look at those benchmark for power drawn on spinup :

http://www.storagereview.com/php/benchmark/bench_sort.php

At startup, when all 12 drive spin up, you have potentially a massive need of those W.

I'd be interested to hear what the geode can do.  I have a perfectly working dual PIII mobo, but it won't boot via USB.  So I'm looking at options that will allow me to recycle any of my old components.  But I can't find many mb that still use PC133 memory.   I really rather not build a box just for unRAID, sort of defeats the purpose.  Just trying to give all my "tiny" 200GB HDs a purpose in life.

While I applaud the effort, I think this may be a case of "great idea, but an inefficient use of your time".

It will be FAR easier to save 0.1KWH of energy elsewhere in your life, unless you already:

* Use CFL's everywhere

* Have insulated your hot water tank and have turned the temp down

* Have verified that you are using ample insulation in the house, including good windows/doors and caulked everything

* ...

If your power bill is $20/month already, then by all means squeeze that last bit of excess energy use out of your life.

Bill

Obviously, part of the project is to find an efficient PS that can meet the needs of the boot process and still be effecient at 20 Watts continuous load. 

Drive spinup surge power is transient, so you have to look at the transient (peak) surge rating for the PS, not the continuous load rating.  Many 200 Watt power supplies will handle a 250 Watt surge for a few seconds.  Also, you should use a controller that staggers powerup to the drives.

My purpose is not to save electricity... but to cut down on the *heat* in my server closet.  I had to remove the door to the server closet and keep a small fan going to keep things cool this summer.

A recent *major* network outage by Rackspace was due to heat.  They had plenty of UPS and backup power... but didn't have backup cooling and within just a few minutes of loss of electricity, servers started to overheat.  I have plenty of UPS for my systems, and don't want to have to shutdown for a 20 minute power outage (which is no uncommon here) but since I can't get UPS monitoring going on unRAID, it can't be set to shutdown on power outage... and some systems I want to run as long as possible (such as Asterisk and home automation interfaces) so I'm trying to minimize the heat generated.

Good points on the heat topic.

Bill

One thing to look for I've just learned about - 80+ certification on the P/S. To get this cert the P/S must be 80% or more effecient over a WIDE range of loads. I noticed that some on NewEgg already display this blue insignia so look for it. Active thermal and power for the P/S would be good too IMO. I also tend to think people oversize P/S, buy a quality one and don't look for a 600Watt beast. The WD green drives are in one of my systems, a couple anyway. It's not a fully loaded system yet but the watt meter is showing some impressive numbers. That things spin down often is nice. Use a low power CPU like a Celeron or maybe even a mobile one adapted. Use 12cm fans but fewer of them, perhaps with a controller to speed them and slow them based on temp...

Hrm, and after having had my power company bounce my power for HOURS while they swapped poles etc. on multiple days I too am looking for UPS support <sigh>

P.S. Heat.. if it is really that bad perhaps considerwater cooling. You can join multiple systems if done right and the heat can be radiated elsewhere but honestly that's a fairly big project. I considered it at one point but I think I'd have to be pretty desperate for cooling to go big with it. One desktop machine on water is quite enough -but very quiet!

Well, I've finished my research, and have the parts on order.

You are absolutely correct that the PS must have a high power factor, and have it at low wattage.  The 80+ certification is a good start.  I've ordered an Antec "EarthWatts" EA380 which has excellent reviews and specs when tested by SPCR, and should give me over 80% efficiency in the range I need.  Of course, picoPSUs can deliver well over 95% efficiency, and if I can find a high-efficiency 200 Watt brick, I may try one.

I'm also going with the WD 1TB green drives.  See http://www.tomshardware.com/2007/10/11/wd_caviar_gp/page8.html#conclusion .  I snagged 3 of them from CC on Black Friday for $199 each.

For CPU I was tempted to go with an ULV special like Cyrix C7 or AMD Geode, but I felt the extra horsepower of a Brisbane core AMD X2 would be needed, so I got a BE-2400, with a TDP of 45 Watts at full power, but which idles at 4 Watts or less.  I have both a Geode and a Cyrix for my Asterix boxes, so I'll be able to do some testing hopefully.

MoBo specs for power usage were hard to pin down.  Based on a lot of reviews, the best low-power consumption chipset is the AMD 690.  Different 690 mobos however, varied widely in power consumption.... and most people suspected the Northbridge as the culprit.... since it got too-hot-to-touch on several high-wattage mobos but remained cool on one -- the Biostar TA690G AM2... so I ordered the Biostar.  When tuned right, idle power consumption on this mobo/CPU combination can be well under 20 Watts.

I'm going to take lots of notes and measurements as I do this.  I'm replacing my existing 12-drive Athlon 64 server that is currently my main file server, and migrating it to unRAID.  It sucks 250 Watts at the wall currently when idle, with C&Q set as aggressive as possible.

With better PSU using active power factor correction, better Mobo, and WD green drives, I hope get the same amount of storage with substantially less than 100 Watts at the wall.

BTW, Newegg just added a new rackmount case -- 4U and 9 bays...perfect for three 4-in-3 or 5-in-3 drive stackers.

Preliminary results from the bench.....

The new Biostar mobo, Antec Earthwatts 380W PSU, and three 1TB WD green drives spun down is a total 50 Watts at idle, measured at the wall outlet.  Airflow exhaust from the PSU is so cool as indistinguishable from ambient.  This is a nice departure from the old box where the PSU exhaust was more like a hair dryer

If I underclock and undervolt the CPU in the BIOS to 1gHz and 1.095 Vcore, I get 31 Watts at idle, measured at the wall outlet.  CPU heatsink is cool to the touch... NB and SB sinks are warm, but not really hot.  The NB is the hottest thing on the mobo, and I can hold my finger on the heatsink for several seconds before it it too hot.  The BIOS has clock.voltage controls for the NB/SB so I may be able to lower them.

I think the Antec's active power-factor correction is fooling the Kill-a-watt meter, as it is showing a power factor of an incredible 0.96 at 31 VA.  But the VA reading is correct, confirmed with a clamp-on meter.  The entire system is only pulling 31 watts from the wall at idle with drives spun down and case fans disconnected.

I'll be timing and measuring specs on a full resync and report all the results (before and after) in a table later.  Right now, I'm unhappy with the cooling fan on the 5-in-1 SATA cage, and the 120MM case fans are way too loud, so I am doing some surgery to put the fans on the 5-Volt rail.

Until the REalTek GigE driver issue is resolved, I had to add an Intel E100B which adds 5 Watts to bring the total to 36 Watts.

As I just purchased the same board I'm curious, what do you mean by "Realtek GigE driver issue"?

The ReakTEK driver in UnRAID 4.2.1 hangs.  You have to disable the RealTek card, or use an older version of unRAID.

...you should use a controller that staggers powerup to the drives.

I believe that this is THE key for using smaller power supplies that will provide higher efficiency ratings at lower power levels.  Does your Biostar motherboard enable this...or have you found an unRaid-supported add-in card that does?

Thanks for all of your research.    I'm going to start building a house next spring that will be Solar powered.  I'm going to have to rethink a lot of my power usage, including my Unraid server.    Your posts are a real help.

...you should use a controller that staggers powerup to the drives.

 

I believe that this is THE key for using smaller power supplies that will provide higher efficiency ratings at lower power levels.  Does your Biostar motherboard enable this...or have you found an unRaid-supported add-in card that does?

Any info. on this previous quesiton? Or which controller r u using that staggers powerup the drives?

I'm interested in this project because I run on battery backup power 6h every single day here in India. Why do I want a 24/7 server? Depending on boot-up times, I might switch it off and on as needed, at least until the power situation improves, but I just spent a month's income on a new hefty battery backup system, so I *could* run a low-ish power box like this.

Anyway, to my question: how many hard drives could one run with a 380w power supply like the earthwatts? I'm looking for around 10 drives eventually (all that local cases can support, unless I start doing PCI cards and eSATA).

To clarify, I'm an American who lives in India, so when I say month's income, I don't mean $200 I have a 3.5kva inverter running off of 4x150 ah batteries. Runs my Mac Pro with 2 massive LCDs 24/7 (slow downloads) and the rest of my lights/fans/tv/projector easily.

Final question - kill-a-watt is only 110. Any way I could get power measurements here in 220land? I had a volt clamp/meter but I couldn't get the info I wanted from it so I sold it.

Rather than deciding on max number of disks why not choose a storage amount target? The WD "green" 1TB drives might be a good choice for this. They vary spindle speed based on demand and are supposed to save a boatload of power. I have several of them and so far no issues - plus they hold a ton I prefer Seagate for their warranty but these were a terrific start on a new build. A good effecient P/S ought to runa few of those but 10 mihgt be pushing it - startup is the biggest power draw you'll find.

Rather than deciding on max number of disks why not choose a storage amount target? The WD "green" 1TB drives might be a good choice for this. They vary spindle speed based on demand and are supposed to save a boatload of power. I have several of them and so far no issues - plus they hold a ton I prefer Seagate for their warranty but these were a terrific start on a new build. A good effecient P/S ought to runa few of those but 10 mihgt be pushing it - startup is the biggest power draw you'll find.

Thanks for the thought. The reason why I'm thinking more in terms of disks than total capacity is because I already have 5-6 disks (of varying sizes/interfaces), I don't have on-going access to the US marketplace, so the idea to be able to just buy any disk available here in India on a whim and toss it in is nice, and finally, it's very hard to accurately predict what I'll need, in terms of storage, down the road. A big reason I'm going with unRAID is to avoid having to buy specific drives and plan sizes/configurations in advance. But I appreciate the advice, seriously. When I'm buying some starter drives, if I can afford 1TB, then those will be the ones I go with.

BLKMGK's comment about a storage target is a reasonable approach.  While 1GB drives aren't the cheapest from a $/MB perspective, they are the cheapest from the MB per start-up power consumption perspective. 

...how many hard drives could one run with a 380w power supply like the earthwatts? I'm looking for around 10 drives eventually ...

Re your hard drive question:  This is entirely driven by start-up power requirements on the PS's 12V rail.  The Antec Earthwatts 380 PS has a max 12V draw of 324W spread across 2 rails (in an ideal world, this would only be 1 rail so you don't have to worry about power distribution).   That means the likely ideal power allocation is in the neighborhood of:

-- 65 W (20%) as a safety factor to account for temperature, PS aging, etc

-- 35 W for an Intel Celeron 4xx series CPU

-- 10-20 W for fans

-- leaving ~200 W for hard disk drives  (assuming no CPU power-on lag and no staggered HDD start-up)

Based on http://www.storagereview.com/1000.sr?page=0%2C6, most of the 1 TB drives have start-up power requirements of 27-30 watts on the 12V rail (with the exception of the very efficient Hitachi drive).  So...if the HDD power requirements can be perfectly balanced across the 2 12V rails, you can power 6-7 hard drives at system start-up.  I may be conservative here (some would say the PS can handle additional surges for brief periods of time, e.g. a startup), but it's possible you will run into trouble above this level.

Smaller drives typically consume less start-up power, but not dramatically.   You might be able to squeeze in another drive.

So...if you already have 5-6 drives, there's not much power headroom left.  If it were me, I'd feel much more comfortable with a larger power supply that has a single 12V rail.  I'm not sure if they are available in India or not, but I'm partial to the Corsair power supplies.  They are highly efficient and typically have a single 12V rail.

Good Karma, indeed Thanks for the thoughts. I'll probably buy my start-up components in the US and have someone bring them out to me. I think you're right, better to go with a 500-600w power supply. 2 of my existing drives are 120gb, so once I get up to 8-10 I'd replace those.

We don't know about staggered start-up with unRAID, right? I've seen a few comments and several questions, but no conclusions? I'm totally Linux-ignorant, so I'll just assume it's a non-starter until I read otherwise. Thanks guys

I have to disagree.

• First off, the largest single impact you can make is going with the Antec PSU.  It's active power factor correction can save you 100 watts in pure wasted power.  I would never consider anything other than an 80+ certified PSU, and one that was thoroughly reviewed, and sized so the continuous load is in the efficiency sweetspot.
   
   
  
• The 1TB Green Drives from Western Digital can make a significant difference.  Their current draw is generally half of conventional drives - or stated conversely, you can have twice as many of them and use the same amount of power.
   
   
  
• If you are using a quality PSU like the Antec, it is OK for the calculated surge current from starting several drives at once to exceed the continuous power rating of the PSU by 25%.  Particularly in a system with mixed models of drives, as they have their peaks and different times, and the peak on the 12v rail is at a different time then the peak on the 5v rail.
   
  
• Even if your mobo controller doesn't do staggered spinup, many PCI controllers do.  So by carefully selecting your second controller, you can have staggered spinup for enough drives to minimize the surge current.
   
  
• The CPU is not the only power hog on the mobo.  Other components, particularly the Northbridge, can pull a lot of juice.  You can have a 40 Watt difference between 2 different motherboards, using the exact same CPU and RAM.  Do some research over at SilentPCReview.com and aviod mobos that have a "blistering hot" NB.
   
  
• Don't overlook the PCI cards.  Video, NIC, and other extra cards use power.  Using the components built into the mobo is almost always going to use less power.
   
  
• If you don't need the horsepower, consider an AMD Geode or other ultra low-power CPU/mobo
   
  
• Consider underclocking and undervolting the CPU in the BIOS.
  

Finally, the AMD cpu's are better and power throttling and using less power when idle.  While you have to jump through some hoops to enable powernow and the on-demand governor under unRAID, it can be done and you can save 20 Watts or more when idle, depending on the CPU model.

Get the Antec Earthwatts... and bite the bullet and get a couple of 1TB of 750GB Western Digital green drives.... sell the old power hungry drives on eBay.  If you absolutely must, Antec has a 500 Watt version of the Earthwatts, but if you get that, you will not be in the sweetspot with continuous operation.

While I'm hesitant to continue to ask questions here for fear or hijacking the thread, I will until it's suggested that I go elsewhere.

So I go searching on Newegg for 80+ certified power supplies and the best 'value' option in my 30 seconds is, in fact, an Antec Earthwatts 430w drive for $60 (less rebate but I don't count those until I cash the check). The extra 50 watts will put my heart at ease.  Looks like the 380w model is out of stock but you can get the 430w model for the same money, even same rebate. Answers the question for me! Thanks guys.

bubbaQ,

We're all in this to build stable, low-power unRaid systems, so please take my comments in that light.

• The 1TB Green Drives from Western Digital can make a significant difference.  Their current draw is generally half of conventional drives - or stated conversely, you can have twice as many of them and use the same amount of power.
   
  

While the Western Digital 1TB Green Drives do wonders for operational power consumption, they do very little for start-up power consumption.  Please see the link in my prior post.

• If you are using a quality PSU like the Antec, it is OK for the calculated surge current from starting several drives at once to exceed the continuous power rating of the PSU by 25%.  Particularly in a system with mixed models of drives, as they have their peaks and different times, and the peak on the 12v rail is at a different time then the peak on the 5v rail.
  

While I've seen PSU surge power capacity mentioned several times, I've never seen any specs, tests, or reviews to back it up.  I'd love to factor in this additional capacity for start-up, but I'm a bit too cautious for that.  Re HDD power peaks...the 12V rail is the only one that really matters.  Most modern PSUs have more than sufficient 5V capacity to meet unRaid's needs.

• Even if your mobo controller doesn't do staggered spinup, many PCI controllers do.  So by carefully selecting your second controller, you can have staggered spinup for enough drives to minimize the surge current.
  

This gets us back to my original question on this thread.  What unRaid-supported PCI controllers stagger HDD spinup?  I don't doubt they exist, I'd just like to make sure I order one.

If there are low-cost PCI controllers with this functionality that aren't supported by unRaid, perhaps Tom can incorporate them into a future build.     This would be another very helpful power efficiency feature.

• The CPU is not the only power hog on the mobo.  Other components, particularly the Northbridge, can pull a lot of juice.  You can have a 40 Watt difference between 2 different motherboards, using the exact same CPU and RAM.  Do some research over at SilentPCReview.com and aviod mobos that have a "blistering hot" NB.
  

Very true and an oversight on my part.  Unfortunately, this only makes the start-up power peak worse.

You mentioned earlier in this post that you were running your unRaid system off an Antec EA380.  Out of curiosity, how many drives are you running?