Running a Raid

Captain Pooka

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I understand that a raid, or atleast the one I'm going to run, runs three hdds as one. However, it combines their RPM and the available space. When I write a program to this drive it writes a third of the program to each, enabling it to read faster and run at about 20,000 RPM. But when one hdd goes out, there is nothing left of this. My intentions are to buy small hdds, but at the price it seems I can get SATA 3.0 160gb at $45 and I can get 80gb for 39.99.. so I'm going to go with the 160s. I might be able to run the RAID in which it writes the whole program to each of the drives, so when one goes out I have two backing it up...

Will this MOBO work for that?

http://www.newegg.com/product/product.aspx?item=N82E16813130136

It has SATA Raid.. but it has 1/0/0+1 and I have no diea what that means.

If I was thinking of running a raid, would I need a water cooling system or a hdd fan of some sort? I would imagine having four drives (one with OS and all my documents and stuff I want to keep, and the RAID with games and stuff on there so they run super fast) would fish up alot of heat in the case..

Now, about the "Programs and games". If I put some animating program on the RAID and I had this huge movie that I was making on the fourth additional hdd, would it be the program that makes it run fast? Or would I have to put the animation file on the raid itsself to make it run faster?
 
I understand that a raid, or atleast the one I'm going to run, runs three hdds as one.

That'll be RAID 5.

However, it combines their RPM and the available space. When I write a program to this drive it writes a third of the program to each, enabling it to read faster and run at about 20,000 RPM. But when one hdd goes out, there is nothing left of this.

You do have fault tolerance on a RAID 5 array which you will find small businesses using for transaction processing and other business systems. So if one drive in the array fails then you still have the infomation on the other 2 drives.

My intentions are to buy small hdds, but at the price it seems I can get SATA 3.0 160gb at $45 and I can get 80gb for 39.99.. so I'm going to go with the 160s. I might be able to run the RAID in which it writes the whole program to each of the drives, so when one goes out I have two backing it up...

Yes but you don't need RAID 5 and the Mobo you chose won't allow a RAID 5 array. However you would use a RAID 1 or RAID 0+1 array which is just as good as a RAID 5 which is only great if you run a small business.


Yep RAID 0, RAID 1 or RAID 0+1

It has SATA Raid.. but it has 1/0/0+1 and I have no idea what that means.

RAID 0 = data striped and interleaved across two drives. But if one drive fails you loose all your data. But this array gives an increase speed in data transfer. Nearly double. Brilliant for Music/Movie editing due to the increased read/write speed to the array.
RAID 1 = data is mirrored on two drives. Access speed might be a little slow but it's not that noticeable and if on drives fails you have all the data on the other. Should this happen you replace the bad drive and re-build the array. Brilliant for storing anything you want to protect due to the fault tolerance it gives.
RAID 0+1 = data is striped on 2 of the drives then the striped data is mirrored on the last 2 drives. You need at least 4 hard discs for this array but it gives you advantages of RAID 0 and RAID 1. Read/Write speed of RAID 0 and the fault tolerance of RAID 1.

If I was thinking of running a raid, would I need a water cooling system or a hdd fan of some sort? I would imagine having four drives (one with OS and all my documents and stuff I want to keep, and the RAID with games and stuff on there so they run super fast) would fish up alot of heat in the case..

They do generate some heat. But you can add fans that blow directly over the discs to keep them cool.

Now, about the "Programs and games". If I put some animating program on the RAID and I had this huge movie that I was making on the fourth additional hdd, would it be the program that makes it run fast? Or would I have to put the animation file on the raid itsself to make it run faster?

This i'll have to get my head round.....:)
 
So RAID 0 and 1 are the same, run at the same speed and everything except in RAID 1 it writes all data to each disk giving you less room?

You can have more than two drives right?

I don't see why you would run a raid 0+1.. If you have 4 100gb 7200 rpm drives and run that then you only have a game running at 14000rpm. Now if you run a raid 1 you have about 30000rpm and 100gb of space (because it writes the same to each drive) and if you run raid 0 then you can lose everything, but you would have 400gb of space and 30000 rpm.

--------------------------------
4 hdds 100gb 7200rpm

0+1 - 200gb space* 14,000rpm (SLOW)
0 - 400gb space - 30,000rpm (Can lose data)
1 - 100gb space - 30,000rpm (Almost impossible to lose data, unless dipped into the Atlantic)

*200gb space because two drives are used for storage and the other two are used for the speed?
--------------------------------

Seems like 0 would be the best, but since I'm going to 160gb space, I am going with raid 1...

Am I understanding this correctly?

Edit*

So looking it up more indepth (Wiki is blocked in our school, and when I type in raid I get WoW lol..) I thought a raid stacks the rpm making stuff SUPER fast.. nothing I see mentions that... ?
 
So RAID 0 and 1 are the same, run at the same speed and everything except in RAID 1 it writes all data to each disk giving you less room?

No. The disks spin at the same speed. The only difference between the different arrays is the read/write access speed.
In this example let's say you want to store data that is 10 bytes. And understand that this is an example.

In a RAID 0 array the 1st byte would store on the 1st drive, the 2nd byte on the 2nd drive, the 3rd byte on the 1st drive, the 4th byte on the 2nd.... and so on, until the 10 bytes is stored. In the above case each stripe is 1 byte in length and is stored on the drives in an interleaved fashion. But in this array if one drive fails you can see now why you would loose the whole 10 bytes. This is RAID 0 or the Striped array.

In a RAID 1 array the 1st byte is stored on both drives, the 2nd byte is stored on both drives... and so on. What ever is on the 1st drive is 'mirrored' on the 2nd drive. This means if one drive fails then the data can be saved from the other drive in the array. This is RAID 1 or the Mirror array.

You can have more than two drives right?

Possibly. It all depends on the RAID controller. RAID 0 uses a minimum of 2 drives. So does RAID 1. RAID 0+1 uses a minimum of 4 drives. RAID 5 uses 3.

I don't see why you would run a raid 0+1.. If you have 4 100gb 7200 rpm drives and run that then you only have a game running at 14000rpm. Now if you run a raid 1 you have about 30000rpm and 100gb of space (because it writes the same to each drive) and if you run raid 0 then you can lose everything, but you would have 400gb of space and 30000 rpm.

Again the arrays don't concern the RPM speed of the disc's. It's more about the read/write speed. I'd run a RAID 0+1 if I wanted the read/write speed of RAID 0 and the data protection of RAID 1. Also the mirroring is usually done slowly to the secondary disk in a RAID 1 array. I see what your saying about RAID 1 but with this array remember that you only need read one drive so the speed isn't the important factor here but it's data protection. With a RAID 0 array the data is read in parallel from both disks giving increased read/write speed. Thats the bonus of RAID 0.

--------------------------------
4 hdds 100gb 7200rpm

0+1 - 200gb space* 14,000rpm (SLOW)
Quite fast actually cause your reading from 1 striped array. The other one is the mirror...
0 - 400gb space - 30,000rpm (Can lose data)
200gb with 2 drives depending on RAID driver.
1 - 100gb space - 30,000rpm (Almost impossible to lose data, unless dipped into the Atlantic)
With the same access speed as with a single drive
*200gb space because two drives are used for storage and the other two are used for the speed?
Yep.
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Seems like 0 would be the best, but since I'm going to 160gb space, I am going with raid 1...

Am I understanding this correctly?

And it can't run Raid 5? That sucks...

Go with RAID 1 if you really need to protect data on the array. If you want speed then go with RAID 0. There are Mobo's that can configure RAID 5. My Mobo has 2 RAID controllers. One of them does RAID 5.

:)
 
+++++ lol... Thanks for putting up with me.

So this is my idea of a raid, simply question. (also my brothers perspective, who told me about raids since I'm trying to build a fast computer.)

Ok, my perspective - Just say your running a 0 raid. I was thinking that since it puts half on one drive and half on the other, it's reading at double the speed, giving it the twice as much RPM effect. Is that right? I got out of your second post that that is wrong.

Same with 1. It puts the whole thing on both drives though, but it still reads half and half giving it the double rpm effect? I know you will still only gave 7200 rpm for each drive, but would the file be reading, theoretically, at 14,000 rmp (with 1 and 0.. and 0+1)?

I just want to know if this is for speed, or for storage. I really don't care about losing anything. If I had a raid it would be for programs. That I can reinstall. Games in particular so with 4 drives in a raid it would give it that 30,000 rmp reading rate effect because it's reading a quarter off of each drive, each at 7200. If it's solely for storage safety, then this is not what I want.. I'll just get 15000s or 10000s.. (SS Is WAY to expensive :D)

Thanks again!
 
:) haha! No worries. Also remember that the speed advantage of some RAID arrays depends on the RAID controller.

+++++ lol... Thanks for putting up with me.

So this is my idea of a raid, simply question. (also my brothers perspective, who told me about raids since I'm trying to build a fast computer.)

Ok, my perspective - Just say your running a 0 raid. I was thinking that since it puts half on one drive and half on the other,
In an interleaved fashion,
it's reading at double the speed, giving it the twice as much RPM effect. Is that right? I got out of your second post that that is wrong.
It's kinda right but again, it's not about the RPM speed. The fact that the data is split, in an interleaved fashion, on the 2 drives means that it's read back in parallel, or at, twice the speed. So if a SATA reads from 1 drive at, lets say, 2Gb/Sec then ,in theory, data from a RAID 0 will be read at 4Gb/Sec. Let's say that you are a RAID controller and you have 2 pigeon boxes in front of you. In one box there's the number's 1,3,5,7,9. And in the other 2,4,6,8,10. And you can use both hands to pick the numbers out and place them, in a stack, in the correct order on a table in front of you. You'll do this task quite quickly.... thats similar to what's going on with RAID 0.

Same with 1. It puts the whole thing on both drives though, but it still reads half and half giving it the double rpm effect? I know you will still only gave 7200 rpm for each drive, but would the file be reading, theoretically, at 14,000 rmp (with 1 and 0.. and 0+1)?
No because the data on each drive is the same as what's on the other drive and it's in one lump. I see what your saying but the RAID controller will just read from the Master drive in this array. The controller usually copies to the other Drive when you change data on the Master and is usually done in the background. So you won't get any performance benefits. Using the 2 pigeon boxes again, as above, but this time you only have to chose which box your going to take the numbers 1-10 from because they both contain the same infomation. So it's one hand, into one box, and grabbing the 1, then 2 then 3... and so on, until you have the stack 1-10 in front of you.

I just want to know if this is for speed, or for storage. I really don't care about losing anything. If I had a raid it would be for programs. That I can reinstall. Games in particular so with 4 drives in a raid it would give it that 30,000 rmp reading rate effect because it's reading a quarter off of each drive, each at 7200. If it's solely for storage safety, then this is not what I want.. I'll just get 15000s or 10000s.. (SS Is WAY to expensive :D)

You've said it right there. So go with the twin RAID 0 array, or a 4 disc RAID 0 if your controller will allow. This will give you, nearly double, read/write speed.

Thanks again!

Anytime....:D
 
Ok! So it's not the rpm I'm looking at it's the "3.0 gb/s" I'm looking at!

Alright, I am going to get two drives and run a 0 raid with that. Thanks! And the chances of one of the hdds failing is the same chance as a normal one, out of a raid, failing... so it's not very high lol...

Just out of curiosity, what does a pata or ide run at (Same interface someone told me. I know SATA runs at 3.0.. that's what I'm getting!!)?

Off topic! But this just came up.. My brother wants to put Wourld of Warcraft on an external hdd. Does it matter if it's Sata or Pata/IDE since it's all going through a usb2? And it wouldn't overheat right?

These look good?

http://www.newegg.com/product/product.aspx?item=N82E16822145162
 
Ok! So it's not the rpm I'm looking at it's the "3.0 gb/s" I'm looking at!
Correct:)

Alright, I am going to get two drives and run a 0 raid with that. Thanks! And the chances of one of the hdds failing is the same chance as a normal one, out of a raid, failing... so it's not very high lol...
That's right. As long as you have the software to put back on the array you'll be fine.

Just out of curiosity, what does a pata or ide run at (Same interface someone told me. I know SATA runs at 3.0.. that's what I'm getting!!)?
Not sure what the transfer speeds of the old PATA drives are but the SATA speeds can reach 3Gb/Sec like you said. I think the old PATA interface wouldn't hit 500Mb/Sec. But don't quote me on that.

Off topic! But this just came up.. My brother wants to put Wourld of Warcraft on an external hdd. Does it matter if it's Sata or Pata/IDE since it's all going through a usb2? And it wouldn't overheat right?

Try and use a SATA drive if you can with a large buffer. USB 1.1 is old school now. And a SATA interface will give you the speed you need. USB 2.0 can transfer data @ up too 480Mb/Sec so go with a decent external SATA drive with USB 2.0 support. And the external drives shouldn't heat up that much that you have to operate them in your refrigerators. :)
 
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