Building a RAID 3.0tb NAS

[ntlord]

I want to build a 3.0tb Raid 5 NAS box (for media files, mostly movies) for around $1500 or less (If that is possible) . I'm really unsure what to get hardware wise. It needs to be rack mountable, so I figured I would build something from scratch and run linux. I have a bunch of questions that I hope someone could answer for me.

1. Should I get a dedicated raid controller, or a mobo with raid on it? It will need a lot of SATA ports so a card could be quite expensive.

2. If I go the motherboard raid route what motherboard chipset would be the best for this.

3. I'm thinking of getting 6x500gb hdd's. The reason being that it will get better storage efficiency with Raid 5 then 4x750gb, any reason I should go the 750 route?

4. If in the future I wanted to upgrade the harddisks, what process would that entail. Could I swap a new one in and rebuild the array? Or do I have to build a second completely separate array and transfer the data.

5. Should I just go the software raid route. This box will be solely dedicated to being a storage server I've heard people saying that if your motherboard or hardware controller breaks you will lose all your data (if you can't find an exact duplicate) in a harware raid scenario, would software raid (linux) fix this?

6. Does anyone have any cheap chassis reccomendations for this? I want hotswappable bays and I was thinking of getting one of those icydock things and just putting that in the 5.25 ports.

7. Any particular harddisk brand reccomendations for those sizes?

Sorry for all the questions,

Dan

 

[Blain]

1. Yes controller, No MB, Yes expensive.
2. Don't.
5. We've covered that one.
6. One with enough open bays.
7. Seagate & WD.

 

[ribbon13]

Run RAID6 on a Areca ARC 1231ML with as many WD5000YS drives as you can afford.

 

[ntlord]

With software raid and a dedicated storage box, how bad performance are we really talking about. Is it going to be unusable? I do like some of the features of software raid. I can easily migrate to large harddisks, and if my hardware fails I'm not screwed. Will I really be able to notice a difference if this is running on its own dedicated machine?

 

[Rubycon]

Originally posted by: ribbon13
Run RAID6 on a Areca ARC 1231ML with as many WD5000YS drives as you can afford.

Why stop with the 1231? 1261 gives another 4 channels for about $100 more. 😀

Also put 2GB ECC cache and battery on that controller and you'll be set. 🙂

 

[ntlord]

Well I think those might be out of my budget a bit, as the 8 port raid cards are like $250, but seriously how bad is software raid going to be, given my situation? I don't mind spending the money on the hardware, but I'm worried about the not being able to get your data back if it fails scenario (unless I find the same card).

 

[Rubycon]

Software RAID still requires a port for each drive so if you have n number of drives you need n number of ports. POSSIBLE on some motherboards if they allow AHCI on all ports. (meaning a single disk, no raid functions)

SW RAID is OK to "get you by" I suppose.

 

[ntlord]

Well a mobo with 8 ports is like $150, so I would just do that. So you saying even if it is a dedicated box, it still will not be good performance? Also if I got the hardware route and it fails, how screwed am I? Are there ways to recover the data, short of sending it away or finding the same card?

 

[Rubycon]

With hardware recovery is on the fly if you choose RAID5 or RAID6 with at least one hotspare disk.

Speed should be satisfactory. If many clients are accessing the box simultaneously performance plummets without the help of a dedicated hardware solution and/or faster spindle speeds.

 

[Blain]

Originally posted by: ntlord
Well I think those might be out of my budget a bit, as the 8 port raid cards are like $250, but seriously how bad is software raid going to be, given my situation? .

You should have mentioned a budget in your original post.
You asked about building a big time 3TB NAS yet it seems like you really don't want to shell out the $$ for a solid setup.
What's your total budget in US dollars?

We're like dogs chasing our tails unless we know how much you're willing to pony up for your storage solution.

 

[MerlinRML]

First of all, just in case you're not aware, you're talking about 3.0TB of RAW storage with what you've indicated about disks. Due to RAID 5 parity information, you will lose either 500GB or 750GB of space depending on which disks you purchase.

1) A dedicated RAID controller is nice because it has its own CPU to do RAID calcalations. If you only have 1 user, and the box is doing nothing else, and it has a decent CPU or two, then the host CPU should be able to easily handle the RAID calculations.

2) NVRAID or MatrixRAID are your 2 best on the motherboard options. However, there's always pure software RAID, which doesn't care about your chipset. As long as it has enough ports and has Linux drivers, you'll be fine.

3) 6x500GB disks will give you more sustained throughput, but it also increases your chances of having disks fail. 4x750GB will give you less performance and have less chance of failure. The thing to note here is that if you're really worred about losing your data, you should still perform backups. RAID is not a backup, it is a way to keep your system running in the event of a disk failure. It doesn't help when you have multiple disk failures or when your power supply blows and takes a disk or two with it.

4) Some controllers support Online Capacity Expansion which would allow you to increase the size of the array while IO is running to it. Then you have to increase the file system. I'm not sure if Software RAID supports this, and it will also require that you pick a filesystem that has tools to extend it or use a LVM.

5) Software RAID is a very viable option. It also fixes the problem with being dedicated to a specific motherboard. A dedicated RAID controller also fixes that problem, as you can move the RAID controller to a new motherboard. With Linux, your array should be moveable to a new system, however it's usually easiest if your OS is not on the RAID array and you can just import your data into a new OS.

6) Your cheapest solution is to use the 3 5.25 bay converters to hold 5 drives. Just make sure you have a decent power supply. I've seen a figure online of about 25 watts per drive. If you get a dedicated RAID card, it may support staggered spinup which would lessen the strain on the power supply at start up.

[EDIT]
I missed seeing your requirement for a rackmount chassis, I think your budget may be a bit tight. Your most dense solution is going to be a 2U chassis which I've seen hold as many as 12 disks or a 1u chassis which could hold 4 if you go the 750GB route. A 4u tower/rack chassis may be cheaper and I've seen some of those that have the drive bay adapters I mentioned, and can hold as many as 10 disks. Either way, I think your case is going to be spendy. I like SuperMicro and AIC chassis pretty well.
[/EDIT]

7) Hitachi, Seagate, WD. They all perform pretty similarly, they all have their issues. They will all fail eventually. I would just get whichever have the most cache, highest capacity, longest warranty, for the lowest price.

Another note. Some OSes do not support volumes greater than 2TB. Windows XP 32-bit does not, for example. Just make sure that if you do create 1 large RAID 5 that the OS can support it and boot from it if your OS resides on the RAID array. Otherwise, you will have wasted space or have to create multiple arrays.

 

[ribbon13]

Originally posted by: Rubycon
Why stop with the 1231? 1261 gives another 4 channels for about $100 more. 😀

Also put 2GB ECC cache and battery on that controller and you'll be set. 🙂

Yeah, that's exactly what I have.

If you care about your massive collection of data, this little beastling is the end all be all of SATA RAID HBAs. Except for it's big brother the ARC-1280ML, but you really shouldn't even look at that given your budget constraints. I couldn't either so don't feel bad 😛 Areca also has some nice looking SAS RAID HBAs on the way.

Anyway, OP, please do yourself a favor and get a real hardware RAID HBA. It's one of those things you don't have to buy too often., and their prices are a lot more steady than other types of pc hardware, and they also retain thier value.