Power Management & HD Choice

[doctor15]

I'm about to build my first NAS (using a Dell T20) and am looking to make it as power efficient as possible. I read through the documentation and forums but found very little information on the Advanced Power Management / Standby settings, other then a few posts discouraging putting the HDs in standby. This NAS is for Home use and one pool will only be used for a max of 6 hours / day (media server), and the other probably only 1-2x/week (documents backup), so I would prefer the power savings and take a chance on decreasing the longevity of drives.

How do the power management settings work and are there any additional pitfalls I should be aware of? Ideally I'm looking for each pool to standby if it has not been used in the past hour or so.

Also, are there any HDs particularly suited for this scenario, or does it not make much of a difference?

 

[solarisguy]

Did you take a look at the laptop drives?

 

[doctor15]

No, why should I consider laptop drives?

I was more thinking along the lines of WD Red, WD Green, Seagate NAS, or Toshiba.

Maybe I'm misunderstanding why people are so anti putting the drive into standby mode. My desktop has run for years with the drives going into standby whenever I'm not on the PC. For my NAS, it just doesn't make sense to have 6 HDs running 24/7 when I only will be using it certain hours.

 

[solarisguy]

I am not anti- ;)

I am only trying to point out that the laptop drives tend to be engineered towards your goals. And, for example, you can have a 2TB WD Green.

FreeNAS users tend to concentrate at having maximum data protection available, while at the same time not paying high prices for data-center-hardware . Powering any electronic devices off and on tends to shorten their life span. Thus keeping the drives spinning allows for them to last longer. That was probably one of the reasons behind hard-drive makers slowing the rotational speed on some models, instead of stopping them altogether (e.g. WD's IntelliPower) when idle.

It is possible that powering your NAS on only once a week does not shorten calendar life span of any of its components (as opposed to keeping them on 24x7), however that is not a scenario an average FreeNAS user has any experience with, and advanced users are likely advanced because they operate systems that are strictly 24x7.

I would look at all the drives with the capacity you desire and select for further consideration the models that have the longest warranty. However, keep in mind that NAS hard-drive makers were not taking into account your needs, not that your drives would be failing, just likely nobody has any long term data about such a usage...

 

[joeschmuck]

You didn't specify which Dell T20 model, if it's the U1 then you are stuck with up to six 2.5" drives (laptop), if the 1U Mini-Tower then you are limited to 6 drives; four 3.5" and two 2.5". Also you don't want to use any RAID in the machine (software or hardware).

Power consumption has always been a large topic and eventually you will figure out that for a small system, even running the hard drives all the time does not consume an appreciable amount of electricity. I think you should consider calculating out how much energy you would save by sleeping the drives. For my WD drives it's about 3 watts per drive between running and sleeping (I think, memory is slipping), so if you consider 3 watts x 6 drives = 18 watts. Now take 18 watts x 30 days (1 month) = 540 watts for a typical month (assuming you never spin the drives up so this is the absolute best case scenario), now times this by the cost of 1KW which for me is about $8.00 per KW (after taxes/fess/all the crap they can think of throwing at you) and I get $4.32/month extra savings just to spin the drives down, and assuming I never spin them up.

Where you will save more money is in the power consumption of the motherboard components, CPU, RAM, Video over the hard drives. You will likely be eating up over 60 watts all the time. Please evaluate power consumptions of all components if you truly want an energy efficient system, but keep in mind that energy efficient can also end up being a rather slow system as well. Your Dell T20 should be fine but it's not going to be forgiving on power consumption.

 

[doctor15]

It's the mini tower. I plan to start with 4 drives (2x1TB mirrored and 2x3TB mirrored), then eventually add 2 more in an external enclosure (for 2x1TB mirrored and 4x3TB in RaidZ). I know that means I'll have to destroy the array when I change to RaidZ but it makes sense for my current use case and budget.

Thanks for the math on power usage. I might get a kill-a-watt and play around with it a bit. Again, coming from a desktop, it just seems logical to for drives to spin down after long periods of inactivity, but I guess that is not the norm. My desktop drives have lasted me for many years with standby settings always enabled.

Anyways I went with WD Reds since they seem to be widely used and have the 3yr warranty. If anyone uses the power management settings on FreeNAS, please chime in with your experience.

As far as the T20 power consumption.. I bought it on a whim but I thought it was relatively efficient server. I'm assuming the processing supports stepping down the power when not in use or a sleep function.

 

[solarisguy]

You may want to start another thread and ask for forum's advice on external disks in RAID-Z...

 

[doctor15]

You may want to start another thread and ask for forum's advice on external disks in RAID-Z...

I'm not completely set on that approach and didn't want to sidetrack this too much. Worst case I'll put out the 1TB array if needed, but one of the reasons this a future plan.

 

[joeschmuck]

I have a Kill-a-watt which is how I measured the power usage for my NAS. It can be very helpful in minimizing your overall power consumption. A simple thing like underclocking your CPU can make a fair change and tweaking video performance, since you really don't need much video in he first place.

As for the WD Red drives, there are a lot of threads here dealing with a parking issue which hopefully your drives will not have but check them out. You can also spin down those drives if you like to and just set the Standby HDD timer value to something like 240 minutes (4 hours) or something at least higher than 120 minutes to ensure you do not spin up and down the drives all the time.

If you plan to use plugins, forget the sleeping of the drives unless you use a separate hard drive for the plugins.

And of course... Get an UPS for the unit and backup any critical data elsewhere in case something happens.

 

[doctor15]

As for the WD Red drives, there are a lot of threads here dealing with a parking issue which hopefully your drives will not have but check them out.

Do the Seagate 7200.14 have a better reputation? I'm not sure if the 7200rpm is ideal for NAS.

 

[joelmusicman]

Do the Seagate 7200.14 have a better reputation? I'm not sure if the 7200rpm is ideal for NAS.

If you're after power savings stick with 5400 drives. I have something like those and they consume double the power of WD Greens and run hotter to boot!

 

[joeschmuck]

Reputation is subjective in most cases but JoelMusicMan pointed out something before I got to it, power consumption is much higher with the higher RPM drives. SSD would be your best bet if you wanted minimal power draw however you pay for it.

 

[joelmusicman]

I also thought about building a big array using laptop drives. Not the cheapest route though, as with few exceptions the largest are 1TB, and the questionable reliability in a 24/7 environment, etc.

 

[solarisguy]

If you think about it from a different angle, then you may realize that laptop drives are reliable.

For example, reading datasheets for current WD Blue (mobile) versus WD Re (datacenter) drives:
* shock (read) 350 vs. 65Gs
* shock non-operating 1000 vs. 300Gs
* operating temperature 0-60 vs. 5-55°C
* seek noise 25 vs. 34dbA (in general, mechanical components that operate less noisy, tend to break less often)

The observed short lifespan of laptop drives comes from the harsh environment an average laptop (ab)user creates for them ;)

Operating laptop hard-drives 24x7 is not what is killing them. It is the amount of data that is getting transferred to and from them. This is where the datacenter drives shine. So for a static storage laptop hard-drives are probably enough, but for a heavy video editing likely not...

 

[joelmusicman]

True, but on the other hand, the motors and bearings are also much smaller, and probably don't last as long.

 

[joeschmuck]

Haven't you ever heard that size doesn't matter ;)