Perhaps you've decided to take the plunge and build your own personal file server. But why bother with dedicated storage hardware when the desktop hard drives in your PC already offer up to 2 TB of capacity? Personally, I built my own file server so that I would have a backup of my data separate from my working PC.
Another good reason to have a networked server is easier access to data from multiple machines. For example, if you have an MP3 collection and want to listen to it from a home theater PC (HTPC) in the living room, it is easier to have all of your music centralized and browse straight to it over the network.
Of course, you can store any collection of files on a server without having to maintain multiple copies of your data on several systems. If the file server is configured to use RAID 5 or RAID 6, it will also be able to withstand a hard drive failure (or two) without data loss, unlike information stored on a desktop PC with a single hard disk.
The Why's Of NAS
There are many different types of file servers. The simplest is a basic external hard drive, which is cheap, fast, and flexible. As long as your data fits on a single disk, that’s perhaps the most economical route to backup your files.
External hard drive enclosures can offer many different interfaces. USB 2.0 is perhaps the most common. It isn't very fast (480 Mb/s), but virtually every computer has USB connectivity. Another popular interface is FireWire. There are two different FireWire speeds: 400 and 800 Mb/s. Most enclosures that support FireWire come equipped with the 400 Mb/s type. In practice, it is even faster than USB. But unfortunately, it’s less ubiquitous than USB. The newest (and fastest) external storage interface is eSATA. Running at 3 Gb/s, it matches the performance of internal SATA ports and is able to serve up more bandwidth than any single mechanical drive is able to saturate.
My old file server. It has a generic case with good airflow.
All of these interfaces, which attach directly to a single computer, are examples of direct-attached storage (DAS). DAS’ strengths are its simplicity, performance, and cost. On the other hand, when the host computer is off, you can’t access any of the files housed on a direct-attached drive. Another limitation stems from connecting directly to a host machine. Generally, only that host will have access to the stored data, and if you try to share the drive over a network, performance on that machine suffers as client systems hammer the DAS device.
The way around the shortcomings of DAS is by not attaching your external storage to a computer at all, but to a network instead via network-attached storage (NAS). As long as a NAS appliance is powered on, it can be accessed from any computer on the network. Chances are good that you’ll attach the device through a single Gigabit Ethernet connection, which should be fast enough for most folks. If it isn’t, you probably won’t be rolling your own file server, but buying a high-end unit with multiple gigabit links, lots of storage space, and support for teaming.
File servers of the DAS and NAS variety often accommodate multiple hard drives. Some enclosures hold two disks and some hold more. The box might support RAID 0 (striping, which can be faster than a single disk), RAID 1 (mirroring, which can protect you against a single disk failure), or RAID 5 (striping with parity, which can also protect you against a single disk failure). Some high-end boxes even support RAID 6, which is similar to RAID 5, but can tolerate two disks failing.
However, these RAID boxes have some limitations. They tend to be expensive. The Qnap TS-509 Pro costs $800 without storage, for example, but does support RAID 5 and 6. With that system, as with most ready-built storage boxes, you’re also forced to use the operating environment that is pre-installed, which might not be as flexible as the software you would prefer. Finally, while some retail NAS boxes can be expanded, most are limited to a single eSATA port or a couple of USB connectors.
So, let's see what we can do using conventional PC hardware to achieve the same NAS goal.

You explain the basic difference between fakeRAID and "read RAID" adequately, but why should I purchase a controller card at all? Motherboards have about six SATA ports, which is enough for your rig on page five. Since your builds are dual-CPU server machines to handle parity and RAID building, am I to assume you're not using a "real RAID" card that does the XOR calculations sans CPU? (HBA = Host Bus Adapter?)
Also, why must your RAID cards support JBOD? You seem to prefer a RAID 5/6 setup. You lost me COMPLETELY there, unless you want to JBOD your OS disk and have the rest in a RAID? In that case, can't you just plug your OS disk into a motherboard SATA port and the rest of the drives into the controller?
And about the CPU: do I really need two of them? You advise "a slow, cheap Phenom II", yet the entire story praises a board hosting two CPUs. Do I need one or two of these Phenoms -- isn't a nice quad core better than two separate dual core chips in terms of price and heat? What if I used a real RAID card to offload the calculations? Then I could use just one dual core chip, right? Or even a nice Conroe-L or Athlon single core?
Finally, no mention of the FreeNAS operating system? I've heard about installing that on a CF reader so I wouldn't need an extra hard drive to store the OS. Is that better/worse than using "any recent Linux" distro? I'm no Linux genius so I was hoping an OS that's tailored to hosting a NAS would help me out instead of learning how to bend a full blown Linux OS to serve my NAS needs. This article didn't really answer any of my first-build NAS questions.
Thanks for the tip about ECC memory, though. I'll do some price comparisons with those modules.
When I meant by experience, I didn't mean by self-learning. I meant developing your own ideas and not doing extensive research on every technical aspects for the specific purpose.
Most IT professionals I have come to recognise in the Storage forum (including myself) can write a far higher caliber article than this.
You explain the basic difference between fakeRAID and "read RAID" adequately, but why should I purchase a controller card at all? Motherboards have about six SATA ports, which is enough for your rig on page five. Since your builds are dual-CPU server machines to handle parity and RAID building, am I to assume you're not using a "real RAID" card that does the XOR calculations sans CPU? (HBA = Host Bus Adapter?)
Also, why must your RAID cards support JBOD? You seem to prefer a RAID 5/6 setup. You lost me COMPLETELY there, unless you want to JBOD your OS disk and have the rest in a RAID? In that case, can't you just plug your OS disk into a motherboard SATA port and the rest of the drives into the controller?
And about the CPU: do I really need two of them? You advise "a slow, cheap Phenom II", yet the entire story praises a board hosting two CPUs. Do I need one or two of these Phenoms -- isn't a nice quad core better than two separate dual core chips in terms of price and heat? What if I used a real RAID card to offload the calculations? Then I could use just one dual core chip, right? Or even a nice Conroe-L or Athlon single core?
Finally, no mention of the FreeNAS operating system? I've heard about installing that on a CF reader so I wouldn't need an extra hard drive to store the OS. Is that better/worse than using "any recent Linux" distro? I'm no Linux genius so I was hoping an OS that's tailored to hosting a NAS would help me out instead of learning how to bend a full blown Linux OS to serve my NAS needs. This article didn't really answer any of my first-build NAS questions.
Thanks for the tip about ECC memory, though. I'll do some price comparisons with those modules.
Seriously, what is this talk about PCI-X and ECC? PCI-X is rare and outdated and ECC is useless and expensive. And dual CPU is not an option, remember electricity gets expensive when your talking 24x7. Get a cheap low power CPU with a full featured board and 6 HDDs and your good to go for much cheaper.
Also your servers are embarrassing.
And I'm worried about RAID 5/6 becoming obsolete because the size of hard drive is becoming so large that error correction is almost impossible to recover when one of the hard drive dies, especially 1 TB sized ones...
I've heard RAID 10 is a must in times of 1-2 TB hard drives are becoming more frequent...
also can you write pro vs con on the slower 1.5-2 TB eco-friendly hard drives that are becoming popular due to low power consumption and heat generation?
Thanks for the great beginner's guide to building your own file server...
Most decent motherboards have RAID support built in but I think most are just RAID 5, 6 or JBOD....
For a long time I had a hardware raid-5 with 4 disk (PCI-X) on dual Athlon MP 1.2 ghz with 2 GB of ECC RAM (Tyan board, forgot exactly model). With hardware raid-5, I don't think you need such powerful CPUs. If I recalled, the raid controller cost about as much as 4x pretty cheap drives (smaller drives since I was doing raid and didn't need THAT much space, it at most 50% for the life of the server, also wanted to limit cost a bit).
Then I decided all I really needed was a Pentium 3 with just 1 large disk (less reliable but good enough for what I needed).
For past year or so, I have not had a fileserver up but planning to rebuild a very low powered one. I was eyeing the Sheeva Plug kind of thing. Or may be even a wireless router with usb storage support (Asus has a few models like that).
Just to show how wide this topic is... :-)
I think you should compare a bit more software raid vs hardware raid. This can greatly change the way someone is gonna build is server. Myself I would not use hardware raid as cards with multiple (4+) SATA connector sporting RAID-5 are way overpriced for the performance I would want to achieve. A home file server is not expected to match entreprise class NAS. And even with an entreprise class server, you need an entreprise class network switch, and good CAT6 cable to link everything together.
I think that a home server should be a bit more than a file server. Do not aim for the most powerful build, you're better off with some more reasonable performance which would be way cheaper, leaving you more cash to buy greater capacity hard drive. One could buy a cheap 6+ SATA connector AM2+ motherboard, get a low-power phenom (905e), invest in 2gig of DDR2 ECC (666Mhz would be ok), and setup a nice home server, capable of doing both file server and a nice back-end for MythTV.
I'm building myself my home server with a old dual IBM Server P3-1.23Ghz with 2.5Gig of ECC SDRAM. I'm looking into replacing it's two current SCSI-160 adapter with two 4-port SATA PCI-X card for a reasonable price (less than a 6+ SATA connector mobo and CPU). I'll be running three VM : My router, my Linux server, and my Windows server. It should be plenty enough for what I want. The only thing that I haven't got to figure out is how to get my Wireless card to be directly accessed by my router VM.
And, yeah, I agree with many of the above, PCI-X strikes me as a weird choice even if you were to still go with a hardware RAID controller.
>I also find it dancing with vagueness as I'm trying to narrow >my parts search. Are you really suggesting we use PCI-X server >motherboards? Why? (Besides the fact that their bandwidth is >separate from normal PCI lanes.) PCI Express has that same >upside, and is much more available in a common motherboard.
There are many possible choices in building a fileserver.
I chose to use motherboards that I already had. Sure
PCI-E is faster and if I were buying all new hardware, I would
use it. However, for those on a budget, $40 will get you a
used motherboard, with 2 cpu's and lots of PCI-X slots at
http://www.surpluscomputers.com/348725/accelertech-tsunami64-dual-amd-opteron.html
You explain the basic difference between fakeRAID and "read RAID" adequately, but why should I purchase a controller card at all? Motherboards have about six SATA ports, which is enough for your rig on page five.
True, the rig on page 5 only had 6 hard drives, and so a
mb with 6 sata ports will work. However that motherboard
has no usable sata ports. Additionally, I have since added
a 7th drive, and the racks allow me to have up to 10 drives.
Clearly, if the mb has enough ports you don't need a controller
card, but I mentioned controller cards for those situations
when the mb doesn't.
>Since your builds are dual-CPU server machines to handle >parity and RAID building, am I to assume you're not using a >"real RAID" card that does the XOR calculations sans CPU? (HBA >= Host Bus Adapter?)
Correct. The real raid cards start around $500, and can easily
cost $1000.
>Also, why must your RAID cards support JBOD? You seem to >prefer a RAID 5/6 setup. You lost me COMPLETELY there, unless >you want to JBOD your OS disk and have the rest in a RAID? In >that case, can't you just plug your OS disk into a motherboard >SATA port and the rest of the drives into the controller?
I said the controller card you buy has to support JBOD.
The Rosewell card calls itself a RAID card (raid 0 and 1),
but it supports JBOD, so you could use it with software RAID.
If the card doesn't support JBOD, you won't be able to use it
with software RAID, (like the SATA controller on the NCCH-DL).
I have all the disks (except the OS disk) using software RAID.
>And about the CPU: do I really need two of them? You advise "a >slow, cheap Phenom II", yet the entire story praises a board >hosting two CPUs. Do I need one or two of these Phenoms -- >isn't a nice quad core better than two separate dual core >chips in terms of price and heat?
When I said CPU, I meant processor. I didn't say two sockets.
You want more than one processor so that one can do the raid
xor calculations. For software it doesn't matter if the
processors are in one or more sockets. If you are buying new
hardware, it is easy to get more than one processor in a single
socket, which is why I recommended the phenom II, with it's 4
cores.
>What if I used a real RAID card to offload the calculations? >Then I could use just one dual core chip, right? Or even a >nice Conroe-L or Athlon single core?
Sure. The only problem is cost. A real RAID card will cost
more than virtually any CPU. If my motherboard fries, I can get
another one, and plug in all of my drives. A new mb and memory
for me will be $100 to $200. If a RAID controller breaks, you
will need to buy another one, which costs $500 - $1000.
There is much more flexibility with software raid and it is
cheaper.
>Finally, no mention of the FreeNAS operating system? I've >heard about installing that on a CF reader so I wouldn't need >an extra hard drive to store the OS. Is that better/worse than >using "any recent Linux" distro? I'm no Linux genius so I was >hoping an OS that's tailored to hosting a NAS would help me >out instead of learning how to bend a full blown Linux OS to
It is certainly a viable option. It is a bit less flexible than
a full linux system, but much easier to set up as you point
out.
>Thanks for the tip about ECC memory, though. I'll do some >price comparisons with those modules.
It isn't much more expensive.
RAID5 and RAID6 aren't going to become obsolete even with big
hard drives. Recovering from a bad hard drive isn't a big deal.
RAID 10 uses almost twice as many drives as RAID-5, and still
tolerates 1 disk failure.
Sure the new drives are bigger than the old ones, but they
are also faster, so recovery doesn't take longer than with old
drives.
I haven't used the eco friendly low power drives, but I have
heard they don't have time limited error recovery, so they
can cause problems with raid controllers or software. Generally
the newer drives use a bit less power than the old ones, due
to increased storage density.
I don't know of any motherboard that does RAID 5 or 6 and has
a XOR engine. Without the XOR engine, the CPU does all of the
work, and you might as well do it all in software.
I was eyeing the Sheeva Plug kind of thing. Or may be even a wireless router with usb storage support (Asus has a few models like that).Just to show how wide this topic is... :-)
I agree. There are many options. I showed two examples of what I have done. The article was longer, but it was cut down a lot.
I have looked at the Sheeva Plug. It is very cute, but only has
one gigabit ethernet and one usb2 port. It could build a nice single disk NAS, but doesn't have the horsepower or bandwidth
to do RAID-5 or 6. I plan on buying one to build a low power bittorrent server...
On the stability side, Windows can EASILY run for months without a restart if it were not for the odd required reboot from security patches. Calling Windows unstable is no better than saying that Max OSX NEVER crashes.
Otherwise, the article is amateurish at best. I see the point of trying to explain why using certain vintages of motherboard is less desirable but really. We are talking about a server for home use where I/O bottlenecks like this are not that big an issue for most people. And yes, physical RAID is all nice in the business world but it is a real pain in the home world.