Building a Low-Power NAS

[whoareyou]

Hello,

I'm trying to build a simple, cheap, low power NAS and would like some input on what to use. The build should have maybe a lot of SATA ports for possible future HDD expansion. Actually, that's pretty much it - a simple, low power, cheap NAS that has room for SATa HDD expansion. Any recommendations would be appreciated.

[DemonWasp]

Either buy an existing NAS box (like the ones Western Digital and pretty well every other company has) buys, or upgrade your router to a model that has USB ports so it can also function as a NAS.

Or, take an old computer, cram a bunch of hard disks in it, and turn it into a server (serving files plus whatever else you want). That's what I did: install hard drives, set up preferred flavour of Linux on mdraid system, run web + source control + file servers off of that box.

[whoareyou]

Well as I don't have an old computer, I was looking for parts I can buy myself. But yeah that's basically the setup I was going for anyways.

[rdrake]

A good starting point would be the total amount of drives, storage capacity, your comfort level with something like Linux or BSD, and a price range.

[DemonWasp]

Also, size, power, noise requirements. Does it need to fit somewhere specific? Does it need to be as low-power as possible? Does it need to be very quiet, a little quiet, or what?

[whoareyou]

Software isn't the problem. I'm jst looking for recommendations for the hardware. Size doesn't matter, should be as low power as possible, noise isn't an issue. Right now I have a 1TB and a 3TB buy I woul like extra SATA ports for future expansion. Also gigabit Ethernet. I'm sure that it wouldn't need ALOT of memory or processing power (ie. my my book live runs a 3tb hard drive using an 800mhz power PC CPU)

[whoareyou]

Should be cheap too (ie. the hard drive should be the most expensive part of the system).

[DemonWasp]

I'll be linking to a few suppliers that I've had good interactions with in this post. Use this post as a starting recommendation, NOT A SHOPPING LIST.

If you really want a cheap, low-power NAS with lots of features, you're probably better off buying an existing solution (all of which are just slower-and-cheaper low-power computers in custom cases). NCIX.ca has a list: Network-Attached Storage. Since you appear to want at least 4 hard drive bays, they seem to start at around $190 with this guy: Sans Digital 4-bay, RAID enabled or only $130 if you don't want RAID support: Sans Digital 4-bay, no RAID . Neither includes hard disks.

If you're more interested in building your own, then you should know that you're signing up for more work, more power consumption, higher price and possibly more noise. I don't want to sound like I'm completely against it (again, this is something I did myself, before consumer/home NAS systems were popular).

You have two main approaches. In the first, you find second-hand gear for cheap: all you really need is a computer with at least 4x SATA2 connections (standard hard drives will not saturate SATA2 yet; if you want SSDs, then you should aim for SATA3). You can probably find a capable machine for relatively cheap, second-hand.

If you want to buy new, then I would suggest one of the latest AMD CPUs as the core of the system. They're cheap, fast, and extremely low-power; the cheapest dual-core A4-3300 is forty-five stupid dollars; however, I would recommend getting a CPU for the newer FM2 socket, such as the A4-5300, at $53.

Get any compatible (CPU socket must match socket on motherboard) mATX motherboard. For maximum expansion, the A85X is hard to beat, with 8x SATA3. I like Gigabyte boards, so here's a suggestion for $85. If you want to go cheaper, the A75 is a close second (6x SATA3), and you can choose the cheaper CPU above, too. For more details, see the Wikipedia comparison.

Toss in whatever RAM looks reasonable. Aim for DDR3-1600 and at least 4GB to have plenty of headroom. Personally, I don't see any sense in buying sets smaller than 8GB or so, because the cost per GB of RAM doesn't go down at all. Here's an 8GB set for $50.

Put the whole mess in a case that will hold all those drives (and the motherboard: cases that say "mATX" or "ATX" will work). If you get a case that includes a power supply, it will be a very low-quality power supply (inefficient, noisy, etc), but you'll avoid paying $100+ for a separate power supply. Anything above 300W should support the build I've outlined here. You can get such a case for as little as $30: http://ncix.com/products/?sku=35528&vpn=CS206BK&manufacture=Logisys%20Computer . I seriously recommend that you look around and find reviews on cases. There's a lot of little details that matter in cases, like whether it rattles or clogs with dust or has hinges that break, etc. Plus, there's no accounting for personal taste, so choose something that appeals to you.

The total for the build above is about $220 (more if you buy a case that isn't at the bottom of the barrel) plus shipping, handling, tax, which brings the total to $280-300 (before hard drives). It will consume all of maybe 20W at the wall in normal operation*. Its primary noise will be from hard disk vibration and the low-quality fans / PSU that are undoubtedly included in that cheap-o case.

*Source: I built a similar computer for a relative. It had an A10-5800K, the suggested motherboard, 32GB RAM, an SSD, and an 80Plus Platinum PSU. I measured its consumption at the wall and the monitor alternated between 0.0W and about 20W when idling; it rose to a steady 70-80W when playing flash games or rendering 1080p YouTube videos and peaked at around 130W when playing 3D videogames. A NAS box should be idling most of the time (file transfer can be considered "idle", as the CPU and graphics card have almost no work to do).

If you have more money to spend, spend it on getting a better case and/or better PSU. For the power supply, you barely need any power to run the system, so get something high-quality in the 300+W range (80Plus Gold or Platinum would be great); if you want it to be nearly-silent then there are also fanless PSUs. For further details on quiet computers, see: http://www.silentpcreview.com/

P.S. To set up your computer, you will probably need to be able to connect it to a monitor you already have. Also, you need to install the OS from a bootable USB drive, or else buy/borrow an optical drive for the OS disks.

[whoareyou]

Thank you very much for your lengthy response.

I've been searching around stumbled upon this:

http://www.newegg.ca/Product/Product.aspx?Item=N82E16813131843

As I don't have a lot of first hand experience with hardware, I'd like to know what you guys think of this board. My intentions are to hook up the drives in concatenation (ie. accessing all the connected drives as a single unit) and to use protocols such as SMB and NFS and such.

[DemonWasp]

That's also an okay option. I should mention that it doesn't appear to have hardware RAID support of any kind, so any RAID or spanning would have to be set up in software. The fact that it's a mini-ITX motherboard means you'll have to find a mini-ITX case (not hard, but it's not compatible with ATX or mATX cases). Make sure you get RAM that's supported: DDR3-1066 or DDR3-800.

I would caution you against a pure concatenation scheme. In such a scheme, if any drive fails, then you could lose all the data on all of the drives. If the probability that a disk dies in any given year is p, then the probability that you don't have a problem is: (1-p)^n, where n is the number of disks involved. Even if p = 0.01 (1% chance of disk failure) and n = 3, then you have nearly a 3% chance of failure (and total data loss) per year.

That's simplified, of course, because disks don't have a flat error rate over their lifetimes. Also, it *might* be possible to recover some files. Google published a study on hard disk reliability a while ago if you want to read more.

My personal preference is for software-managed RAID5. I've successfully dealt with hard disk failures with only a day of downtime and no lost data: just replace the disk and tell mdraid to fix the array. If you're not up for learning about mdraid, though, your best options are either hardware RAID or leaving the disks as independent. That way, if one fails, at least it doesn't bring down the others.

[whoareyou]

Are you sure the dual core 1.0GHz would be sufficient enough for my specific build? I should probably say that my NAS build is almost like an expanded version of a My Book Live NAS. I think what you've outlined in one of your previous posts with the YouTube streaming and video games is not what I'm looking to build. It's just simply hooking up a bunch of drives for access over my network. Does more disk capacity require more computing power or is it only somewhat dependent on the amount of memory available or is it completely irrelevant?

Also, what about the MTBF ratings on these WD Red drives? I think most if them have a rating of 1,000,000 hours before failure. These disks aren't going to be under a lot of heavy load. Just for simple storage and read access 95% of the time.

Isn't RAID5 capacity limited to the drive with the least amount of space? I can't remember but with the way I'm going to be using my HDDs, I don't think there'd be a need for redundancy. What do you think?

[whoareyou]

What about http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157324

The CPU is only single core but for my purposes should it be enough? Also, at what speed might this CPU do transfers at over gbit LAN since it seems to be the limiting factor of the board? Hopefully greater than 10MBps.

[DemonWasp]

I'm going to assume you're talking about SMB sharing, which is what Windows uses. It's also available on Linux, OSX, and most other platforms.

Adding disk capacity does NOT increase CPU requirements. The CPU requirements will mostly be in pulling data off of the disks and packaging it up with whatever sharing software you're using (presumably Samba or the built-in Windows SMB support), and in any case those aren't terribly high. Even at the maximum rate of gigabit ethernet (roughly 90MB/s transfer rates) your CPU should be spending most of its time sleeping. That said, if you want your server to occasionally do other things, like transcode video files, run a database, etc, then you might stress your CPU slightly more.


I'm having a hard time finding any actual tests where people have tried a C-60 based NAS. I think it will work just fine, but you might run into a performance ceiling on the CPU. The A4-5300 I suggested is nearly 4 times as fast, while the A4-3300 is about 3 times as fast. Sources: AMD C-60 and AMD A4-5300. That said, the C-60 should be fast enough to serve files across the network just fine.

I should mention that I don't have any low-end CPUs. The slowest thing I've got in operation is the Intel Core 2 Duo T5450 in my laptop, which is about 50% faster than the C-60. Even my ancient AMD Athlon 1900+ (now 13 years old) manages 60% the speed (by PC-Mark rating) of the C-60. Given that said ancient CPU could probably push data across the network that fast, the C-60 should be just fine.

If you're worried about performance but want to save money right now, you could consider buying the C-60 and potentially upgrading it later if you have serious problems with it (which I doubt).


The bit about YouTube streaming was just verification that my suggested build would consume very little power. Obviously, this C-60 build would consume even less.


MTBF ratings are largely garbage. Here's an overview of the study Google did on their big data centres: http://storagemojo.com/2007/02/19/googles-disk-failure-experience/ . Long story short, hard drives fail WAAAAAY more frequently than MTBF numbers would indicate. Remember that 1,000,000 hours is 114 years anyway, which is longer than the magnetic substrate on the actual disk platters could be reasonably expected to stick around.

Remember that 114 years ago, it was 1899, humans didn't know how to make airplanes, World War I wouldn't start for another 15 years, and the assembly line was still 14 years away. The quoted timeframe is ridiculous. Plus, MTBF numbers typically assume that the drive isn't active very much, whereas NAS drives are online and spinning 100% of the time. That said, I've had pretty good results with WD Green drives, and they have a good warranty program.

The best way to keep your hard drives reliable is to keep them fairly cool -- ideally below 40C. Even a simple case fan should do that, provided your case isn't clogged with dust or blocked from getting fresh air.


RAID5 is limited to the capacity of the smallest device, and requires at least 3 drives. Given as you have a 1TB drive and a 3TB drive, RAID5 is probably not the right choice for you. The only way to answer the question of "do I need redundancy?" is to ask yourself "if this drive dies (today, tomorrow, next week, next month, next year, in three years), will I cry?". If not, then you don't need redundancy; if yes, then you'd better get to learning about RAID and backups and so forth.

[DemonWasp]

Whoops, missed your latest post. The E-240 is very light on the CPU power, at roughly 83% the performance of the C-60. For $7 more (listed at $70 vs $77), definitely choose the C-60.

I can't guarantee it, but I believe that the C-60 should be able to push a file transfer at the maximum rate afforded by gigabit LAN, which is around 80-90MB/s for SMB.

[whoareyou]

That's more than enough speed. I think I'll get the C-60. Now I just need to find a cheap power supply. I don't really need a case, in fact I prefer the mobo to be visible.