HDD Standby, APM and read/write head parking

[Leary]

With almost 200 Euros energy costs per year for my 5 bay NAS, I thought it needs a little improvement. Mainly, because I only use it around 8 hours per day (depending on working times sometimes at day, sometimes at night so I don't want to set an on/off timetable).

As far as I have read, there are 3 interacting processes which could help saving energy. All of them could also effect the lifetime of a disk, which I would have to risk but still try to make the effect as small as possible.

HDD Standby: I thought about setting this to 60 minutes. This would affect the system waking up only 1 or 2 times each day. Do you think thats a good compromise?

Advanced Power Management: I'm not really sure how that interacts with the HDD Standby? Is it meant that APM is activated after the 60 minutes of the HDD Standby? I thought about setting this to 64 since I read that number sometimes before in this concern. Would you agree?

Read/write head parking: So here is another thing which I'm not sure about. Correct me if I'm wrong but it seems that WD (I have a mix of different drives, most of them are from WD) has a power saving feature installed directly into the harddrive. With the tool WDIDLE3 it seems to be possible to change this feature and it is recommended by some to set it to 5 minutes, which I don't understand why.
I thought about deactivating this on all my WD drives so there is no bad interaction with the power saving settings of FreeNAS. Would you agree with that idea?

Overall I hope I can cut my energy settings in half with those settings and will measure the energy consumption after setting it up.

It would be nice if you could give me your opinion about those 3 changes I've planned.

 

[Nick2253]

First off, it'd be nice to have your hardware config, so we have some basis in recommending any fixes. Also, your per kwh energy cost and idle wattage would help with providing context.

I'm personally opposed to standbying drives. The power use of an idling drive is extremely low already. Even if there is significant power to be saved, you also have to weigh that against the increased wear of the drives caused by shutting down and starting up (and the corresponding thermal shock of relatively rapid cooling down and warming up).

Head parking is in the same vein. You're not going to see hardly any power savings from parking heads, but you'll dramatically increase the wear on your drives if you ratchet up the head parking.

To be honest, if you think you can save 50% of your server's electricity cost by idling your drives, you're going to have a bad time. Even hyper-efficient servers (like Avotons) with lots of drives would only see a power savings of 10-20% with the changes you're talking about, and they would already be in the ~50W range for power consumption.

 

[Leary]

My Setup is:

Build FreeNAS-9.10.1 (d989edd)
Platform Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz
Memory 7859MB
Mainboard: ASRock > H61M-ITX
Drives:
2x WD Red 4tb
(3x WD blue 4tb added end of the week)

Consumption measuring
Energy Consumption normally: 35 Watt
With power saving options (standy time 5 min, APM 64): after 15 min still 35 Watt
Same with APM 1 after 15 min still 35

So you are right. It seems like the energy saving is not doing very much.
This is not compliance with this source I just found:
http://www.storagereview.com/western_digital_red_nas_hard_drive_review_wd30efrx
WD Red Power 2TB/3TB: read/write 4.4W, idle 4.1W, standby/sleep 0.6W
So normally the watt consumption should drop from 35 to 27. And with 5 drives in it, it should drop from 47 to 27.

What an odd thing that there is no difference. My energy meter is working correctly, I tested it with other devices.

About shutting it off and on: How much does the energy boost when waking drives actually affect the longterm performance? Are there any studies suggesting a significant effect? I'm just very curious about this topic since the temp difference souldnt be that huge, only about 10-20° which shouldnt effect an expansion of the built material.
My main PC has different drives, the oldest must be 7 years. Every day I turn it off and on and the drives are working perfectly fine. I'm just not sure if it would be so much different for the NAS?

So your opinion about head parking is to definitely turn it off? Since I thought it's always activated by default when buying a WD drive and deactivating is a bit tricky and an uncommon thing.

 

[CraigD]

To honest I think your current setup is energy efficient, keep your drives spinning, I doubt purchasing more power efficient hardware will save you money

 

[Leary]

Thanks CraidG
But actually I'm not planning on buying new hardware, I just want to figure out if its possible to make some setting changes which could make it more energy efficient since I'm only using the system a couple of hours per day.

 

[Nick2253]

I would expect you to see some power savings, so I'm guessing that either something on your system is keeping your pool awake, or you've got something misconfigured. But, like I said, I don't expect that power savings to be that significant.

I'd actually be curious myself what the quantified impact of turning drives on and off does to the drive. From a generic sense, start/stop cycles are bad for electric motors, though a particular motor's sensitivity to start/stop cycles is largely dependent on the construction and design of that motor.

Honestly, if you really want to save ~10W, I'd look around your home and figure out other places to save. My guess is that an upgrade of any appliance to a high-efficiency one would save you many more watts, at a relatively small cost compared to the total energy savings. I mean, we're talking 240Whr a day here, which is the same as running a 60W bulb for eight hours.

 

[MrToddsFriends]

First off: Energy consumption wise your system is in the same ballpark as mine (roughly 35W) and I do live in Germany just like you (I'm assuming 26ct/kWh). If I didn't make a dumb mistake, 80 EUR per year is a valid estimate for energy costs. 200 Euros per year as stated by you seems pretty much to me.

I don't let my HDDs spin down for the reasons already mentioned by Nick2253 but if you are feeling adventurous feel free to read on here (EDIT: Are your really sure that any of your HDDs actually spun down during your measurements?):
https://forums.freenas.org/index.php?threads/how-to-let-drives-spin-down.26314/
https://forums.freenas.org/index.ph...ut-if-a-drive-is-spinning-down-properly.2068/
After having played around with HDD Standby and APM for some time (back then as I built my system) I think this is a waste of time.

About (undesirable!) head parking and desirable HDD features (AFAIK the new WD Blue series are rebranded WD Greens):
https://forums.freenas.org/index.php?threads/hacking-wd-greens-and-reds-with-wdidle3-exe.18171/
https://forums.freenas.org/index.php?threads/checking-for-tler-erc-etc-support-on-a-drive.27126/

 

[Nick2253]

First off: Energy consumption wise your system is in the same ballpark as mine (roughly 35W) and I do live in Germany just like you (I'm assuming 26ct/kWh). If I didn't make a dumb mistake, 80 EUR per year is a valid estimate for energy costs. 200 Euros per year as stated be you seems pretty much to me.

FYI, I get ~80 EUR doing the math as well.

35W * 24hours/day * 365 days/year * €0.26/kwh = €79.72/yr.

 

[Leary]

Sorry if I expressed myself wrong but the 35W was with only 2 WD red drives in it. End of the week there will be 3 WD blue added and the almost 200€ of my first post was a calculation for the 5 bays. Still, 200 is probably a bit high calculated, you are right.

Even if the WD blue would also consume as little power as the WD red (idle 4.1W, standby/sleep 0.6W) the drives on themselfes (without the system) would consume 20W or 480W/h per day, while putting them in standby 16 hours per day (during sleep and work) would only be 170W/h.

Anyway, money is an argument but it's also an inner drive of mine to try improving things, finding the screw you have to twist to make things more efficient and "not letting the light on when you are not at home". FreeNAS provides those settings and probably put a lot of work in it to develop those so I thought it might be interesting if there is a good compromise of using them.

I still find it odd that the energy saving settings didnt do anything which I will assess again after all the backups are done and I finally added the new drives and set the system up again. I still have some problems of understanding the interaction of the 2 settings (standby and APM) mentioned in the first post but I will set all my drives to 300s head parking now after reading the links of MrToddsFriends. But what exactly affects a spindown now? The standby setting or only the APM level 1? Since I planned on using Standby 60 min and APM level 64 there shouldnt be a spindown right?

 

[MrToddsFriends]

Even if the WD blue would also consume as little power as the WD red (idle 4.1W, standby/sleep 0.6W) the drives on themselfes (without the system) would consume 20W or 480W/h per day, while putting them in standby 16 hours per day (during sleep and work) would only be 170W/h.

Have a look at the spec sheets for Red and Blue drives
http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-800002.pdf
http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771436.pdf
Using those numbers the difference between spin-down and not-to-spin-down is even smaller. I think the storagereview designations are just values from older WD spec sheets.

I still have some problems of understanding the interaction of the 2 settings (standby and APM) mentioned in the first post but I will set all my drives to 300s head parking now after reading the links of MrToddsFriends. But what exactly affects a spindown now? The standby setting or only the APM level 1? Since I planned on using Standby 60 min and APM level 64 there shouldnt be a spindown right?

AFAIK the APM level is identical to the argument to the -B parameter of hdparm
http://man7.org/linux/man-pages/man8/hdparm.8.html
so values 1 through 127 should permit spin-down. Aside from the the caveats mentioned in the first link I provided above spin-down might not work as expected in each and every FreeNAS version as this feature is not seen as a high priority one (at least this is how I see it).

 

[tvsjr]

Also bear in mind that, ignoring the wear you'll put on the drives stopping and starting them, keeping a spinning drive spinning uses comparatively small amounts of power. If you stop the drive, you have to spin it back up... this will be harder on the power supply and will cause substantially increased load and heat generation as everything spins back up.

Look at it this way... you do all this and *maybe* you save 25% a year. That's 20EUR. What's a new drive cost? 100EUR? If you kill a drive every 5 years due to the increased stress of starting/stopping, you haven't saved any money.

 

[Stux]

Also, the system dataset will periodically be written to. If the dataset is on your drives, your drives won't sleep.

If your drives do sleep, they'll need to be spun up again. Will the spin up burn more power than was saved?

If you spin up your drives a few times a day, will they prematurely fail? If so a replacement drive will need to be manufactured and purchased. That's probably going to wipe out any green savings and dollar savings.

Why not just use a script which shuts down your NAS when it's not in use and a Wake On Lan command before you need it ;)

I actually got this working on my backup NAS before I decided to add more tasks to its job. Ie it would be turned on via WOL a few minutes before the replication and after the replication I sent it a shutdown command.