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Help me figure out a RAID solution, please.
May 3, 2006 2:58 PM   Subscribe

Instead of getting a four-bay Firewire enclosure, could I just get a cheap PC case and use that to build a RAID?

So I need a place to store a ton of data. I put together a 2-drive RAID a couple years ago - bought a firewire enclosure, hooked up a couple old drives, and there it went.

Well, now I'm looking for a way to take ALL of my DVDs and put them on one central server that I can access from around the house.

My original thinking was to get four 250GB drives and a four-bay FW enclosure and make it that way. But 4-bay enclosures seem to be ~$175. Add to that ~$360 for the drives and I'm looking at more than I really want to spend. So what if I got a smallish cheap PC case instead of the FW enclosure? They have power supplies, room enough, Firewire ports...

Am I going about this all wrong? Can I get a 1TB drive cheaper or easier?
posted by ImJustRick to Computers & Internet (18 answers total) 1 user marked this as a favorite
 
Well if you're going to get 1TB out of four 250GB drives, you're just doing RAID 0 (not technically making a Redundant Array of Independant Disks) and gon't get much out of the redundancy hardware (power supplies, separate controllers, &c.) available in real RAID enclosures. So, go ahead and use any box that will stripe or concatenate the disks.
posted by nicwolff at 3:22 PM on May 3, 2006


I'm confused. If you're planning to turn a cheap PC into a network server that makes sense, but I don't see how you could turn one into a FireWire enclosure. How are you planning on bridging from FireWire to ATA?
posted by cillit bang at 3:32 PM on May 3, 2006


A cheap PC and a RAID controller or software RAID would work fine, but I'm guessing that's not what you mean. Then you'd need a fully functional PC and I don't imagine the cost would be less than $175 for that.

All the other scenarios I can imagine don't seem doable. If you mean simply buy the PC case with no motherboard, then you'd have a couple of problems. Firstly the power supply won't turn on without interaction with the motherboard, secondly... do they even make internal firewire drives? Even then you'd need to throw a firewire hub in there and each drive would appear as a distinct firewire device, not the single RAID-0 combined device the enclosure would give you.

If I understand the question, and you're asking if a regular $40-$50 (or more) PC case alone will do the job, I'd say the answer is almost certainly no.
posted by mragreeable at 3:33 PM on May 3, 2006


It's going to matter (a lot) what you actually want to do with this drive. Do you want to stream DVD video off it to some point source somewhere? If so, how is it going to be networked? Simply setting up a cheapie linux box and sharing the whole TB as a SAMBA share won't work, unless you have a very fast (like, 100 Base-T) network in your home. Remember also that even if your cheap linux box has a 100 Base-T NIC and your delivery point is also compatible, ordinary Cat5 networking won't work between them.

I'm doing precisely what you describe in my home, but it has required a major investment of time and money and it still doesn't quite work as I'd like it to. (I'm using dedicated network attached storage from a fantastic company called Infrant that I've pimped so many times in the green I'm not even going to bother to link to it, but feel free to email if you want details).
posted by The Bellman at 3:43 PM on May 3, 2006


A cheap PC and a RAID controller or software RAID would work fine, but I'm guessing that's not what you mean. Then you'd need a fully functional PC and I don't imagine the cost would be less than $175 for that.

This doesn't have to cost much money, any PII or higher system will be plenty (maybe as little as $50). Adding SATA ports to such an old system will cost a bit, maybe $10-15 per port. 100 megabit ethernet is plenty for playing back DVD quality video over the network, I do it all the time, and it is super cheap. I'm not exactly sure what The Bellman is thinking of.
posted by Chuckles at 4:38 PM on May 3, 2006


You are talking about using the PC case and power supply just to house the drives, while next door you have the actual PC with the Firewire RAID adapter, right? Basically, you want to use the PC case just for the power but won't actually have a motherboard installed.
A company I used to work for did this with SCSI drives back in the day. It works fine. Make sure the power supply in the case has enough juice, although with 4 drives and nothing else that shouldn't be a problem.
Also, nicwolff is righ, if you want to get any redundancy, you'll have to sacrifice one of the drives (assuming you go RAID 5), which will knock you down to about 750GB.
posted by Eddie Mars at 4:46 PM on May 3, 2006


Thanks for the responses.

To clarify:

1. I suppose I won't stream the movies. Let's assume for now that I'm going to connect it, via Firewire, to a Mac Min attached to my plasma.

2. I'll be using cheapish internal ATA drives, about 250 Gigs apiece. But I don't want four distinct drives; I want one megadrive. (And yeah, I know it won't be a full TB)

3. So the case would be for power and for the fw interface only.
posted by ImJustRick at 4:57 PM on May 3, 2006


But 4-bay enclosures seem to be ~$175. Add to that ~$360 for the drives and I'm looking at more than I really want to spend.

You're going to have to pay for the drives one way or another, so their cost is a moot point.

The question is, is it cheaper to get a FW enclosure, set up a computer with a decent RAID controller and put it on the network, utilize a NAS device, or any number of other solutions.

If you're really strapped for cash, my suggestion would be to get a big, cheap beast of a tower case and put your current system in it, then get a decent RAID card (Promise TX2000s are good, reliable and cheap) and 4 drives. That's the cheapest solution. You'll probably need a beefier power supply, to boot. Total cost: about $200, not including the drives.

A cheap used system can be found for peanuts, the problem is you've got to find one with a case large enough to hold 4 drives.

NAS devices are out of your price range.
posted by Civil_Disobedient at 5:06 PM on May 3, 2006


Oh, you're using a Mac. Well, that kinda sucks if you're trying to pinch pennies. My revised suggestion: get a cheap system from Retrobox (linked above), transfer it to a cheap, big case, get the RAID card I mentioned, and get a beefy power supply for the drives. Probably cost you $300 (again, not including drives).

If you opt for firewire drives, you're going to pay big, big bucks per Gig.
posted by Civil_Disobedient at 5:12 PM on May 3, 2006


If you plan to RAID them (RAID 5 would leave you 750gb of space, and would be the best cost< ->hassle tradeoff, especially if a drive fails, since you won't have to re-rip all those DVDs), you'll need an external box WITH a RAID controller built in. A simple enclosure only has an interface (say, FireWire) to act as a pass-through to ONE drive -- most enclosures don't have a RAID controller in them.

My suggestion is to take the NAS route; find the cheapest barebones system you can find that has a RAID controller and that'll take four 3.5" drives, and run Ubuntu or some other Linux distro on it. Doesn't really matter for streaming DVDs if the controller is a "high end" one, just that it'll do RAID 5 in hardware (since you might find it difficult to find a driver for Linux). It won't be cheap, but it'll be cheaper than buying a Terastation or some other similar product.
posted by Merdryn at 6:16 PM on May 3, 2006


FYI: Common RAID levels:

RAID 0: Striped. You'd have 1000GB of space, but NO fault tolerance at all -- one drive fails, you've lost 25% of the bits from each file, since the files are striped across all drives. Can use two or more drives.

RAID 1: Mirrored. Needs an even number of identical drives (for most controllers). You'd have 500GB of space, but every single bit of recorded data would have a mirror image. Two drives could bite it (as long as they were different halves of each pairing).

RAID 3: Dedicated Parity. 750GB of space, fairly rare to find in hardware (nearly impossible in software) since it requires a good deal of "math" on the controller. You could lose one drive and still recover. Three drives would have data, one drive would have "parity data", used to rebuild one of the other three drives if one fails.

RAID 5: Distributed Parity. 750GB of space, fairly common to find in hardware and software, but writing can be a bit slow (and reading becomes slow when a drive fails). Each drive has bits of files as well as parity bits to rebuild another drive if a drive fails.

RAID 0+1: Stripe+Mirror: Two striped drives mirrored on two mirror drives. 500GB of space. You get all the speed of RAID 0 (which is blindingly fast with good drives) and the fault tolerance of RAID 1, at the cost of 1/2 your disk space.

There is also RAID 2,4,6,10 and 50, but you rarely see those in the real world (and you never see 2; I don't know if there are ANY controllers that will do RAID 2)
posted by Merdryn at 6:24 PM on May 3, 2006


So the case would be for power and for the fw interface only

I'm still confused. By case do you mean "PC"? What's going to be between the drives and the FireWire port?
posted by cillit bang at 6:36 PM on May 3, 2006


The voice of reason says just put the DVD into the player when you want to watch it.
posted by JamesMessick at 6:39 PM on May 3, 2006


I'm assuming there is some sort of software RAID solution you are planning on using, in which case you'll still need to pop for some ATA-Firewire bridges. The one's I've seen run about $50 each. I think each will support two drives. Still, you aren't saving much going that route.
posted by Good Brain at 7:10 PM on May 3, 2006


PC cases don't have Firewire interfaces. That's a feature of the computer inside a case, not the enclosure itself. At best, you're going to need some kind of ATA-to-Firewire adapter for each of the devices, then to chain them together, and to run the cable through a hole in the case. Based on your misunderstanding this, it doesn't sound like this is going to be all that ideal a project for you.

The general consensus the last time this question was asked was that what you're trying to accomplish is not likely to be worth the effort.
posted by majick at 8:55 PM on May 3, 2006


Why in heavens are people suggesting the firewire route? This is someone trying to save money.

As I said above, it's really quite simple. Done and done.
posted by Civil_Disobedient at 4:18 AM on May 4, 2006


Simply setting up a cheapie linux box and sharing the whole TB as a SAMBA share won't work, unless you have a very fast (like, 100 Base-T) network in your home. Remember also that even if your cheap linux box has a 100 Base-T NIC and your delivery point is also compatible, ordinary Cat5 networking won't work between them.

I think you mean Gigabit (1000BaseT) and not 100BaseT.
A 100MBit/s (100BaseTX) network is not "very fast", it's standard. It also works perfectly with Cat5 cables (that's what it's designed for).

If you are talking about a 1GBit/s network though, what you said is correct. It is "very fast", needs Gigabit NICs and switches and Cat5e cables instead of Cat5.

However, for watching a movie from a DVD image on a file server, a 100MBit/s network is perfectly sufficient.
posted by bloo at 5:44 AM on May 4, 2006


Bloo: thanks for correcting my brainfart, I did indeed mean 1000BaseT.
posted by The Bellman at 10:08 AM on May 4, 2006


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